2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
6 <refentry id=
"systemd.network" conditional='ENABLE_NETWORKD'
7 xmlns:
xi=
"http://www.w3.org/2001/XInclude">
10 <title>systemd.network
</title>
11 <productname>systemd
</productname>
15 <refentrytitle>systemd.network
</refentrytitle>
16 <manvolnum>5</manvolnum>
20 <refname>systemd.network
</refname>
21 <refpurpose>Network configuration
</refpurpose>
25 <para><filename><replaceable>network
</replaceable>.network
</filename></para>
29 <title>Description
</title>
31 <para>A plain ini-style text file that encodes network configuration for matching network interfaces,
33 <citerefentry><refentrytitle>systemd-networkd
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
34 See
<citerefentry><refentrytitle>systemd.syntax
</refentrytitle><manvolnum>7</manvolnum></citerefentry>
35 for a general description of the syntax.
</para>
37 <para>The main network file must have the extension
<filename>.network
</filename>; other
38 extensions are ignored. Networks are applied to links whenever the links appear.
</para>
40 <para>The
<filename>.network
</filename> files are read from the files located in the system network
41 directories
<filename>/usr/lib/systemd/network
</filename> and
42 <filename>/usr/local/lib/systemd/network
</filename>, the volatile runtime network directory
43 <filename>/run/systemd/network
</filename> and the local administration network directory
44 <filename>/etc/systemd/network
</filename>. All configuration files are collectively sorted and processed
45 in lexical order, regardless of the directories in which they live. However, files with identical
46 filenames replace each other. Files in
<filename>/etc/
</filename> have the highest priority, files in
47 <filename>/run/
</filename> take precedence over files with the same name under
48 <filename>/usr/
</filename>. This can be used to override a system-supplied configuration file with a local
49 file if needed. As a special case, an empty file (file size
0) or symlink with the same name pointing to
50 <filename>/dev/null
</filename> disables the configuration file entirely (it is
"masked").
</para>
52 <para>Along with the network file
<filename>foo.network
</filename>, a
"drop-in" directory
53 <filename>foo.network.d/
</filename> may exist. All files with the suffix
54 <literal>.conf
</literal> from this directory will be merged in the alphanumeric order and parsed
55 after the main file itself has been parsed. This is useful to alter or add configuration settings,
56 without having to modify the main configuration file. Each drop-in file must have appropriate
57 section headers.
</para>
59 <para>In addition to
<filename>/etc/systemd/network
</filename>, drop-in
<literal>.d
</literal>
60 directories can be placed in
<filename>/usr/lib/systemd/network
</filename> or
61 <filename>/run/systemd/network
</filename> directories. Drop-in files in
62 <filename>/etc/
</filename> take precedence over those in
<filename>/run/
</filename> which in turn
63 take precedence over those in
<filename>/usr/lib/
</filename>. Drop-in files under any of these
64 directories take precedence over the main network file wherever located.
</para>
68 <title>[Match] Section Options
</title>
70 <para>The network file contains a [Match] section, which determines if a given network file may be
71 applied to a given device; and a [Network] section specifying how the device should be configured. The
72 first (in lexical order) of the network files that matches a given device is applied, all later files
73 are ignored, even if they match as well.
</para>
75 <para>A network file is said to match a network interface if all matches specified by the [Match]
76 section are satisfied. When a network file does not contain valid settings in [Match] section, then the
77 file will match all interfaces and
<command>systemd-networkd
</command> warns about that. Hint: to avoid
78 the warning and to make it clear that all interfaces shall be matched, add the following:
79 <programlisting>Name=*
</programlisting> The following keys are accepted:
</para>
81 <variablelist class='network-directives'
>
82 <xi:include href=
"systemd.link.xml" xpointer=
"mac-address" />
83 <xi:include href=
"systemd.link.xml" xpointer=
"permanent-mac-address" />
84 <xi:include href=
"systemd.link.xml" xpointer=
"path" />
85 <xi:include href=
"systemd.link.xml" xpointer=
"driver" />
86 <xi:include href=
"systemd.link.xml" xpointer=
"type" />
87 <xi:include href=
"systemd.link.xml" xpointer=
"property" />
90 <term><varname>Name=
</varname></term>
92 <para>A whitespace-separated list of shell-style globs matching the device name, as exposed
93 by the udev property
<literal>INTERFACE
</literal>, or device's alternative names. If the
94 list is prefixed with a
"!", the test is inverted.
</para>
99 <term><varname>WLANInterfaceType=
</varname></term>
101 <para>A whitespace-separated list of wireless network type. Supported values are
102 <literal>ad-hoc
</literal>,
<literal>station
</literal>,
<literal>ap
</literal>,
103 <literal>ap-vlan
</literal>,
<literal>wds
</literal>,
<literal>monitor
</literal>,
104 <literal>mesh-point
</literal>,
<literal>p2p-client
</literal>,
<literal>p2p-go
</literal>,
105 <literal>p2p-device
</literal>,
<literal>ocb
</literal>, and
<literal>nan
</literal>. If the
106 list is prefixed with a
"!", the test is inverted.
112 <term><varname>SSID=
</varname></term>
114 <para>A whitespace-separated list of shell-style globs matching the SSID of the currently
115 connected wireless LAN. If the list is prefixed with a
"!", the test is inverted.
121 <term><varname>BSSID=
</varname></term>
123 <para>A whitespace-separated list of hardware address of the currently connected wireless
124 LAN. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example in
125 <varname>MACAddress=
</varname>. This option may appear more than once, in which case the
126 lists are merged. If the empty string is assigned to this option, the list is reset.
</para>
130 <xi:include href=
"systemd.link.xml" xpointer=
"host" />
131 <xi:include href=
"systemd.link.xml" xpointer=
"virtualization" />
132 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-command-line" />
133 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-version" />
134 <xi:include href=
"systemd.link.xml" xpointer=
"architecture" />
135 <xi:include href=
"systemd.link.xml" xpointer=
"firmware" />
141 <title>[Link] Section Options
</title>
143 <para>The [Link] section accepts the following keys:
</para>
145 <variablelist class='network-directives'
>
147 <term><varname>MACAddress=
</varname></term>
149 <para>The hardware address to set for the device.
</para>
153 <term><varname>MTUBytes=
</varname></term>
155 <para>The maximum transmission unit in bytes to set for the
156 device. The usual suffixes K, M, G, are supported and are
157 understood to the base of
1024.
</para>
158 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
159 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
163 <term><varname>ARP=
</varname></term>
165 <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol)
166 for this interface is enabled. When unset, the kernel's default will be used.
</para>
167 <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
168 interfaces atop a single lower-level physical interface, which will then only serve as a
169 link/
"bridge" device aggregating traffic to the same physical link and not participate in
170 the network otherwise. Defaults to unset.
</para>
174 <term><varname>Multicast=
</varname></term>
176 <para>Takes a boolean. If set to true, the multicast flag on the device is enabled. Defaults to unset.
</para>
180 <term><varname>AllMulticast=
</varname></term>
182 <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the network.
183 This happens when multicast routing is enabled. Defaults to unset.
</para>
187 <term><varname>Promiscuous=
</varname></term>
189 <para>Takes a boolean. If set to true, promiscuous mode of the interface is enabled.
190 Defaults to unset.
</para>
191 <para>If this is set to false for the underlying link of a
<literal>passthru
</literal> mode MACVLAN/MACVTAP,
192 the virtual interface will be created with the
<literal>nopromisc
</literal> flag set.
</para>
196 <term><varname>Unmanaged=
</varname></term>
198 <para>Takes a boolean. When
<literal>yes
</literal>, no attempts are
199 made to bring up or configure matching links, equivalent to
200 when there are no matching network files. Defaults to
201 <literal>no
</literal>.
</para>
202 <para>This is useful for preventing later matching network
203 files from interfering with certain interfaces that are fully
204 controlled by other applications.
</para>
208 <term><varname>Group=
</varname></term>
210 <para>Link groups are similar to port ranges found in managed switches. When network interfaces
211 are added to a numbered group, operations on all the interfaces from that group can be
212 performed at once. Takes an unsigned integer in the range
0…
2147483647. Defaults to unset.
217 <term><varname>RequiredForOnline=
</varname></term>
219 <para>Takes a boolean or a minimum operational state and an optional maximum operational state.
220 Please see
<citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
221 for possible operational states. When
<literal>yes
</literal>, the network is deemed required when
222 determining whether the system is online (including when running
223 <command>systemd-networkd-wait-online
</command>). When
<literal>no
</literal>, the network is ignored
224 when determining the online state. When a minimum operational state and an optional maximum operational
225 state are set,
<literal>yes
</literal> is implied, and this controls the minimum and maximum
226 operational state required for the network interface to be considered online.
</para>
228 <para>Defaults to
<literal>yes
</literal> when
<varname>ActivationPolicy=
</varname> is not set,
229 or set to
<literal>up
</literal>,
<literal>always-up
</literal>, or
<literal>bound
</literal>.
230 Defaults to
<literal>no
</literal> when
<varname>ActivationPolicy=
</varname> is set to
231 <literal>manual
</literal> or
<literal>down
</literal>. This is forced to
<literal>no
</literal>
232 when
<varname>ActivationPolicy=
</varname> is set to
<literal>always-down
</literal>.
</para>
234 <para>The network will be brought up normally (as configured by
<varname>ActivationPolicy=
</varname>),
235 but in the event that there is no address being assigned by DHCP or the
236 cable is not plugged in, the link will simply remain offline and be
237 skipped automatically by
<command>systemd-networkd-wait-online
</command>
238 if
<literal>RequiredForOnline=no
</literal>.
</para>
242 <term><varname>RequiredFamilyForOnline=
</varname></term>
244 <para>Takes an address family. When specified, an IP address in the given family is deemed required
245 when determining whether the link is online (including when running
246 <command>systemd-networkd-wait-online
</command>). Takes one of
<literal>ipv4
</literal>,
247 <literal>ipv6
</literal>,
<literal>both
</literal>, or
<literal>any
</literal>. Defaults to
248 <literal>any
</literal>. Note that this option has no effect if
249 <literal>RequiredForOnline=no
</literal>, or if
<literal>RequiredForOnline=
</literal> specifies a
250 minimum operational state below
<literal>degraded
</literal>.
</para>
254 <term><varname>ActivationPolicy=
</varname></term>
256 <para>Specifies the policy for
<command>systemd-networkd
</command> managing the link
257 administrative state. Specifically, this controls how
<command>systemd-networkd
</command>
258 changes the network device's
<literal>IFF_UP
</literal> flag, which is sometimes
259 controlled by system administrators by running e.g.,
<command>ip link set dev eth0 up
</command>
260 or
<command>ip link set dev eth0 down
</command>, and can also be changed with
261 <command>networkctl up eth0
</command> or
<command>networkctl down eth0
</command>.
</para>
263 <para>Takes one of
<literal>up
</literal>,
<literal>always-up
</literal>,
264 <literal>manual
</literal>,
<literal>always-down
</literal>,
<literal>down
</literal>,
265 or
<literal>bound
</literal>. When
<literal>manual
</literal>,
<command>systemd-networkd
</command>
266 will not change the link's admin state automatically; the system administrator must bring the
267 interface up or down manually, as desired. When
<literal>up
</literal> (the default) or
268 <literal>always-up
</literal>, or
<literal>down
</literal> or
<literal>always-down
</literal>,
269 <command>systemd-networkd
</command> will set the link up or down, respectively,
270 when the interface is (re)configured. When
<literal>always-up
</literal> or
271 <literal>always-down
</literal>,
<command>systemd-networkd
</command> will set the link up
272 or down, respectively, any time
<command>systemd-networkd
</command> detects a change in
273 the administrative state. When
<varname>BindCarrier=
</varname> is also set, this is
274 automatically set to
<literal>bound
</literal> and any other value is ignored.
</para>
276 <para>When the policy is set to
<literal>down
</literal> or
<literal>manual
</literal>,
277 the default value of
<varname>RequiredForOnline=
</varname> is
<literal>no
</literal>.
278 When the policy is set to
<literal>always-down
</literal>, the value of
279 <varname>RequiredForOnline=
</varname> forced to
<literal>no
</literal>.
</para>
281 <para>The administrative state is not the same as the carrier state, so using
282 <literal>always-up
</literal> does not mean the link will never lose carrier. The link
283 carrier depends on both the administrative state as well as the network device's physical
284 connection. However, to avoid reconfiguration failures, when using
<literal>always-up
</literal>,
285 <varname>IgnoreCarrierLoss=
</varname> is forced to true.
</para>
292 <title>[SR-IOV] Section Options
</title>
293 <para>The [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to configure
294 several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource into virtual
295 PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV improves
296 north-south network performance (that is, traffic with endpoints outside the host machine) by allowing
297 traffic to bypass the host machine’s network stack.
</para>
299 <variablelist class='network-directives'
>
301 <term><varname>VirtualFunction=
</varname></term>
303 <para>Specifies a Virtual Function (VF), lightweight PCIe function designed solely to move data
304 in and out. Takes an unsigned integer in the range
0…
2147483646. This option is compulsory.
</para>
309 <term><varname>VLANId=
</varname></term>
311 <para>Specifies VLAN ID of the virtual function. Takes an unsigned integer in the range
1…
4095.
</para>
316 <term><varname>QualityOfService=
</varname></term>
318 <para>Specifies quality of service of the virtual function. Takes an unsigned integer in the range
1…
4294967294.
</para>
323 <term><varname>VLANProtocol=
</varname></term>
325 <para>Specifies VLAN protocol of the virtual function. Takes
<literal>802.1Q
</literal> or
326 <literal>802.1ad
</literal>.
</para>
331 <term><varname>MACSpoofCheck=
</varname></term>
333 <para>Takes a boolean. Controls the MAC spoof checking. When unset, the kernel's default will be used.
</para>
338 <term><varname>QueryReceiveSideScaling=
</varname></term>
340 <para>Takes a boolean. Toggle the ability of querying the receive side scaling (RSS)
341 configuration of the virtual function (VF). The VF RSS information like RSS hash key may be
342 considered sensitive on some devices where this information is shared between VF and the
343 physical function (PF). When unset, the kernel's default will be used.
</para>
348 <term><varname>Trust=
</varname></term>
350 <para>Takes a boolean. Allows to set trust mode of the virtual function (VF). When set, VF
351 users can set a specific feature which may impact security and/or performance. When unset,
352 the kernel's default will be used.
</para>
357 <term><varname>LinkState=
</varname></term>
359 <para>Allows to set the link state of the virtual function (VF). Takes a boolean or a
360 special value
<literal>auto
</literal>. Setting to
<literal>auto
</literal> means a
361 reflection of the physical function (PF) link state,
<literal>yes
</literal> lets the VF to
362 communicate with other VFs on this host even if the PF link state is down,
363 <literal>no
</literal> causes the hardware to drop any packets sent by the VF. When unset,
364 the kernel's default will be used.
</para>
369 <term><varname>MACAddress=
</varname></term>
371 <para>Specifies the MAC address for the virtual function.
</para>
378 <title>[Network] Section Options
</title>
380 <para>The [Network] section accepts the following keys:
</para>
382 <variablelist class='network-directives'
>
384 <term><varname>Description=
</varname></term>
386 <para>A description of the device. This is only used for
387 presentation purposes.
</para>
391 <term><varname>DHCP=
</varname></term>
393 <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
394 <literal>yes
</literal>,
<literal>no
</literal>,
395 <literal>ipv4
</literal>, or
<literal>ipv6
</literal>. Defaults
396 to
<literal>no
</literal>.
</para>
398 <para>Note that DHCPv6 will by default be triggered by Router
399 Advertisement, if that is enabled, regardless of this parameter.
400 By enabling DHCPv6 support explicitly, the DHCPv6 client will
401 be started regardless of the presence of routers on the link,
402 or what flags the routers pass. See
403 <literal>IPv6AcceptRA=
</literal>.
</para>
405 <para>Furthermore, note that by default the domain name
406 specified through DHCP is not used for name resolution.
407 See option
<option>UseDomains=
</option> below.
</para>
409 <para>See the [DHCPv4] or [DHCPv6] sections below for further configuration options for the DHCP
410 client support.
</para>
414 <term><varname>DHCPServer=
</varname></term>
416 <para>Takes a boolean. If set to
<literal>yes
</literal>, DHCPv4 server will be started. Defaults
417 to
<literal>no
</literal>. Further settings for the DHCP server may be set in the [DHCPServer]
418 section described below.
</para>
422 <term><varname>LinkLocalAddressing=
</varname></term>
424 <para>Enables link-local address autoconfiguration. Accepts
<option>yes
</option>,
425 <option>no
</option>,
<option>ipv4
</option>, and
<option>ipv6
</option>. An IPv6 link-local address
426 is configured when
<option>yes
</option> or
<option>ipv6
</option>. An IPv4 link-local address is
427 configured when
<option>yes
</option> or
<option>ipv4
</option> and when DHCPv4 autoconfiguration
428 has been unsuccessful for some time. (IPv4 link-local address autoconfiguration will usually
429 happen in parallel with repeated attempts to acquire a DHCPv4 lease).
</para>
431 <para>Defaults to
<option>no
</option> when
<varname>KeepMaster=
</varname> or
432 <varname>Bridge=
</varname> is set or when the specified
433 <varname>MACVLAN=
</varname>/
<varname>MACVTAP=
</varname> has
<varname>Mode=passthru
</varname>, or
434 <option>ipv6
</option> otherwise.
</para>
438 <term><varname>IPv6LinkLocalAddressGenerationMode=
</varname></term>
440 <para>Specifies how IPv6 link local address is generated. Takes one of
441 <literal>eui64
</literal>,
<literal>none
</literal>,
<literal>stable-privacy
</literal> and
442 <literal>random
</literal>. When unset,
<literal>stable-privacy
</literal> is used if
443 <varname>IPv6StableSecretAddress=
</varname> is specified, and if not,
444 <literal>eui64
</literal> is used. Note that if
<varname>LinkLocalAddressing=
</varname> is
445 <literal>no
</literal> or
<literal>ipv4
</literal>, then
446 <varname>IPv6LinkLocalAddressGenerationMode=
</varname> will be ignored. Also, even if
447 <varname>LinkLocalAddressing=
</varname> is
<literal>yes
</literal> or
448 <literal>ipv6
</literal>, setting
<varname>IPv6LinkLocalAddressGenerationMode=none
</varname>
449 disables to configure an IPv6 link-local address.
</para>
453 <term><varname>IPv6StableSecretAddress=
</varname></term>
455 <para>Takes an IPv6 address. The specified address will be used as a stable secret for
456 generating IPv6 link-local address. If this setting is specified, and
457 <varname>IPv6LinkLocalAddressGenerationMode=
</varname> is unset, then
458 <varname>IPv6LinkLocalAddressGenerationMode=stable-privacy
</varname> is implied.
459 If this setting is not specified, and
<literal>stable-privacy
</literal> is set to
460 <varname>IPv6LinkLocalAddressGenerationMode=
</varname>,
461 then a stable secret address will be generated from the local machine ID and the interface
466 <term><varname>IPv4LLRoute=
</varname></term>
468 <para>Takes a boolean. If set to true, sets up the route needed for
469 non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
475 <term><varname>DefaultRouteOnDevice=
</varname></term>
477 <para>Takes a boolean. If set to true, sets up the default route bound to the interface.
478 Defaults to false. This is useful when creating routes on point-to-point interfaces.
479 This is equivalent to e.g. the following,
480 <programlisting>ip route add default dev veth99
</programlisting>
482 <programlisting>[Route]
483 Gateway=
0.0.0.0</programlisting></para>
484 <para>Currently, there are no way to specify e.g., the table for the route configured by
485 this setting. To configure the default route with such an additional property, please use
486 the following instead:
487 <programlisting>[Route]
489 Table=
1234</programlisting></para>
493 <term><varname>LLMNR=
</varname></term>
495 <para>Takes a boolean or
<literal>resolve
</literal>. When true,
497 url=
"https://tools.ietf.org/html/rfc4795">Link-Local
498 Multicast Name Resolution
</ulink> on the link. When set to
499 <literal>resolve
</literal>, only resolution is enabled,
500 but not host registration and announcement. Defaults to
501 true. This setting is read by
502 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
506 <term><varname>MulticastDNS=
</varname></term>
508 <para>Takes a boolean or
<literal>resolve
</literal>. When true,
510 url=
"https://tools.ietf.org/html/rfc6762">Multicast
511 DNS
</ulink> support on the link. When set to
512 <literal>resolve
</literal>, only resolution is enabled,
513 but not host or service registration and
514 announcement. Defaults to false. This setting is read by
515 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
519 <term><varname>DNSOverTLS=
</varname></term>
521 <para>Takes a boolean or
<literal>opportunistic
</literal>. When true, enables
522 <ulink url=
"https://tools.ietf.org/html/rfc7858">DNS-over-TLS
</ulink> support on the link.
523 When set to
<literal>opportunistic
</literal>, compatibility with non-DNS-over-TLS servers
524 is increased, by automatically turning off DNS-over-TLS servers in this case. This option
525 defines a per-interface setting for
526 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
527 global
<varname>DNSOverTLS=
</varname> option. Defaults to unset, and the global setting
528 will be used. This setting is read by
529 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
533 <term><varname>DNSSEC=
</varname></term>
535 <para>Takes a boolean or
<literal>allow-downgrade
</literal>. When true, enables
536 <ulink url=
"https://tools.ietf.org/html/rfc4033">DNSSEC
</ulink> DNS validation support on
537 the link. When set to
<literal>allow-downgrade
</literal>, compatibility with non-DNSSEC
538 capable networks is increased, by automatically turning off DNSSEC in this case. This
539 option defines a per-interface setting for
540 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
541 global
<varname>DNSSEC=
</varname> option. Defaults to unset, and the global setting will be
542 used. This setting is read by
543 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
548 <term><varname>DNSSECNegativeTrustAnchors=
</varname></term>
549 <listitem><para>A space-separated list of DNSSEC negative
550 trust anchor domains. If specified and DNSSEC is enabled,
551 look-ups done via the interface's DNS server will be subject
552 to the list of negative trust anchors, and not require
553 authentication for the specified domains, or anything below
554 it. Use this to disable DNSSEC authentication for specific
555 private domains, that cannot be proven valid using the
556 Internet DNS hierarchy. Defaults to the empty list. This
558 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
562 <term><varname>LLDP=
</varname></term>
564 <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol commonly
565 implemented on professional routers and bridges which announces which physical port a system is connected
566 to, as well as other related data. Accepts a boolean or the special value
567 <literal>routers-only
</literal>. When true, incoming LLDP packets are accepted and a database of all LLDP
568 neighbors maintained. If
<literal>routers-only
</literal> is set only LLDP data of various types of routers
569 is collected and LLDP data about other types of devices ignored (such as stations, telephones and
570 others). If false, LLDP reception is disabled. Defaults to
<literal>routers-only
</literal>. Use
571 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry> to query the
572 collected neighbor data. LLDP is only available on Ethernet links. See
<varname>EmitLLDP=
</varname> below
573 for enabling LLDP packet emission from the local system.
578 <term><varname>EmitLLDP=
</varname></term>
580 <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the special values
581 <literal>nearest-bridge
</literal>,
<literal>non-tpmr-bridge
</literal> and
582 <literal>customer-bridge
</literal>. Defaults to false, which turns off LLDP packet emission. If not false,
583 a short LLDP packet with information about the local system is sent out in regular intervals on the
584 link. The LLDP packet will contain information about the local hostname, the local machine ID (as stored
585 in
<citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and the
586 local interface name, as well as the pretty hostname of the system (as set in
587 <citerefentry><refentrytitle>machine-info
</refentrytitle><manvolnum>5</manvolnum></citerefentry>). LLDP
588 emission is only available on Ethernet links. Note that this setting passes data suitable for
589 identification of host to the network and should thus not be enabled on untrusted networks, where such
590 identification data should not be made available. Use this option to permit other systems to identify on
591 which interfaces they are connected to this system. The three special values control propagation of the
592 LLDP packets. The
<literal>nearest-bridge
</literal> setting permits propagation only to the nearest
593 connected bridge,
<literal>non-tpmr-bridge
</literal> permits propagation across Two-Port MAC Relays, but
594 not any other bridges, and
<literal>customer-bridge
</literal> permits propagation until a customer bridge
595 is reached. For details about these concepts, see
<ulink
596 url=
"https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE
802.1AB-
2016</ulink>. Note that
597 configuring this setting to true is equivalent to
<literal>nearest-bridge
</literal>, the recommended and
598 most restricted level of propagation. See
<varname>LLDP=
</varname> above for an option to enable LLDP
604 <term><varname>BindCarrier=
</varname></term>
606 <para>A link name or a list of link names. When set, controls the behavior of the current
607 link. When all links in the list are in an operational down state, the current link is brought
608 down. When at least one link has carrier, the current interface is brought up.
</para>
610 <para>This forces
<varname>ActivationPolicy=
</varname> to be set to
<literal>bound
</literal>.
</para>
614 <term><varname>Address=
</varname></term>
616 <para>A static IPv4 or IPv6 address and its prefix length,
617 separated by a
<literal>/
</literal> character. Specify
618 this key more than once to configure several addresses.
619 The format of the address must be as described in
620 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
621 This is a short-hand for an [Address] section only
622 containing an Address key (see below). This option may be
623 specified more than once.
626 <para>If the specified address is
<literal>0.0.0.0</literal> (for IPv4) or
<literal>::
</literal>
627 (for IPv6), a new address range of the requested size is automatically allocated from a
628 system-wide pool of unused ranges. Note that the prefix length must be equal or larger than
8 for
629 IPv4, and
64 for IPv6. The allocated range is checked against all current network interfaces and
630 all known network configuration files to avoid address range conflicts. The default system-wide
631 pool consists of
192.168.0.0/
16,
172.16.0.0/
12 and
10.0.0.0/
8 for IPv4, and fd00::/
8 for IPv6.
632 This functionality is useful to manage a large number of dynamically created network interfaces
633 with the same network configuration and automatic address range assignment.
</para>
638 <term><varname>Gateway=
</varname></term>
640 <para>The gateway address, which must be in the format
642 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
643 This is a short-hand for a [Route] section only containing
644 a Gateway key. This option may be specified more than
649 <term><varname>DNS=
</varname></term>
651 <para>A DNS server address, which must be in the format described in
652 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
653 This option may be specified more than once. Each address can optionally take a port number
654 separated with
<literal>:
</literal>, a network interface name or index separated with
655 <literal>%
</literal>, and a Server Name Indication (SNI) separated with
<literal>#
</literal>.
656 When IPv6 address is specified with a port number, then the address must be in the square
657 brackets. That is, the acceptable full formats are
658 <literal>111.222.333.444:
9953%ifname#example.com
</literal> for IPv4 and
659 <literal>[
1111:
2222::
3333]:
9953%ifname#example.com
</literal> for IPv6. If an empty string is
660 assigned, then the all previous assignments are cleared. This setting is read by
661 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
665 <term><varname>Domains=
</varname></term>
667 <para>A whitespace-separated list of domains which should be resolved using the DNS servers on
668 this link. Each item in the list should be a domain name, optionally prefixed with a tilde
669 (
<literal>~
</literal>). The domains with the prefix are called
"routing-only domains". The
670 domains without the prefix are called
"search domains" and are first used as search suffixes for
671 extending single-label hostnames (hostnames containing no dots) to become fully qualified
672 domain names (FQDNs). If a single-label hostname is resolved on this interface, each of the
673 specified search domains are appended to it in turn, converting it into a fully qualified domain
674 name, until one of them may be successfully resolved.
</para>
676 <para>Both
"search" and
"routing-only" domains are used for routing of DNS queries: look-ups for hostnames
677 ending in those domains (hence also single label names, if any
"search domains" are listed), are routed to
678 the DNS servers configured for this interface. The domain routing logic is particularly useful on
679 multi-homed hosts with DNS servers serving particular private DNS zones on each interface.
</para>
681 <para>The
"routing-only" domain
<literal>~.
</literal> (the tilde indicating definition of a routing domain,
682 the dot referring to the DNS root domain which is the implied suffix of all valid DNS names) has special
683 effect. It causes all DNS traffic which does not match another configured domain routing entry to be routed
684 to DNS servers specified for this interface. This setting is useful to prefer a certain set of DNS servers
685 if a link on which they are connected is available.
</para>
687 <para>This setting is read by
688 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
689 "Search domains" correspond to the
<varname>domain
</varname> and
<varname>search
</varname> entries in
690 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
691 Domain name routing has no equivalent in the traditional glibc API, which has no concept of domain
692 name servers limited to a specific link.
</para>
696 <term><varname>DNSDefaultRoute=
</varname></term>
698 <para>Takes a boolean argument. If true, this link's configured DNS servers are used for resolving domain
699 names that do not match any link's configured
<varname>Domains=
</varname> setting. If false, this link's
700 configured DNS servers are never used for such domains, and are exclusively used for resolving names that
701 match at least one of the domains configured on this link. If not specified defaults to an automatic mode:
702 queries not matching any link's configured domains will be routed to this link if it has no routing-only
703 domains configured.
</para>
707 <term><varname>NTP=
</varname></term>
709 <para>An NTP server address (either an IP address, or a hostname). This option may be specified more than once. This setting is read by
710 <citerefentry><refentrytitle>systemd-timesyncd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
714 <term><varname>IPForward=
</varname></term>
715 <listitem><para>Configures IP packet forwarding for the
716 system. If enabled, incoming packets on any network
717 interface will be forwarded to any other interfaces
718 according to the routing table. Takes a boolean,
719 or the values
<literal>ipv4
</literal> or
720 <literal>ipv6
</literal>, which only enable IP packet
721 forwarding for the specified address family. This controls
722 the
<filename>net.ipv4.ip_forward
</filename> and
723 <filename>net.ipv6.conf.all.forwarding
</filename> sysctl
724 options of the network interface (see
<ulink
725 url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
726 for details about sysctl options). Defaults to
727 <literal>no
</literal>.
</para>
729 <para>Note: this setting controls a global kernel option,
730 and does so one way only: if a network that has this setting
731 enabled is set up the global setting is turned on. However,
732 it is never turned off again, even after all networks with
733 this setting enabled are shut down again.
</para>
735 <para>To allow IP packet forwarding only between specific
736 network interfaces use a firewall.
</para>
740 <term><varname>IPMasquerade=
</varname></term>
741 <listitem><para>Configures IP masquerading for the network interface. If enabled, packets
742 forwarded from the network interface will be appear as coming from the local host. Takes one
743 of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
<literal>both
</literal>, or
744 <literal>no
</literal>. Defaults to
<literal>no
</literal>. If enabled, this automatically sets
745 <varname>IPForward=
</varname> to one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal> or
746 <literal>yes
</literal>.
</para>
747 <para>Note. Any positive boolean values such as
<literal>yes
</literal> or
748 <literal>true
</literal> are now deprecated. Please use one of the values in the above.
</para>
752 <term><varname>IPv6PrivacyExtensions=
</varname></term>
753 <listitem><para>Configures use of stateless temporary
754 addresses that change over time (see
<ulink
755 url=
"https://tools.ietf.org/html/rfc4941">RFC
4941</ulink>,
756 Privacy Extensions for Stateless Address Autoconfiguration
757 in IPv6). Takes a boolean or the special values
758 <literal>prefer-public
</literal> and
759 <literal>kernel
</literal>. When true, enables the privacy
760 extensions and prefers temporary addresses over public
761 addresses. When
<literal>prefer-public
</literal>, enables the
762 privacy extensions, but prefers public addresses over
763 temporary addresses. When false, the privacy extensions
764 remain disabled. When
<literal>kernel
</literal>, the kernel's
765 default setting will be left in place. Defaults to
766 <literal>no
</literal>.
</para></listitem>
769 <term><varname>IPv6AcceptRA=
</varname></term>
770 <listitem><para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the
771 interface. If true, RAs are accepted; if false, RAs are ignored. When RAs are accepted, they may
772 trigger the start of the DHCPv6 client if the relevant flags are set in the RA data, or if no
773 routers are found on the link. The default is to disable RA reception for bridge devices or when IP
774 forwarding is enabled, and to enable it otherwise. Cannot be enabled on bond devices and when link
775 local addressing is disabled.
</para>
777 <para>Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA] section, see
780 <para>Also see
<ulink
781 url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink> in the kernel
782 documentation regarding
<literal>accept_ra
</literal>, but note that systemd's setting of
783 <constant>1</constant> (i.e. true) corresponds to kernel's setting of
<constant>2</constant>.
</para>
785 <para>Note that kernel's implementation of the IPv6 RA protocol is always disabled,
786 regardless of this setting. If this option is enabled, a userspace implementation of the IPv6
787 RA protocol is used, and the kernel's own implementation remains disabled, since
788 <command>systemd-networkd
</command> needs to know all details supplied in the advertisements,
789 and these are not available from the kernel if the kernel's own implementation is used.
</para>
793 <term><varname>IPv6DuplicateAddressDetection=
</varname></term>
794 <listitem><para>Configures the amount of IPv6 Duplicate
795 Address Detection (DAD) probes to send. When unset, the kernel's default will be used.
799 <term><varname>IPv6HopLimit=
</varname></term>
800 <listitem><para>Configures IPv6 Hop Limit. For each router that
801 forwards the packet, the hop limit is decremented by
1. When the
802 hop limit field reaches zero, the packet is discarded.
803 When unset, the kernel's default will be used.
807 <term><varname>IPv4AcceptLocal=
</varname></term>
808 <listitem><para>Takes a boolean. Accept packets with local source addresses. In combination
809 with suitable routing, this can be used to direct packets between two local interfaces over
810 the wire and have them accepted properly. When unset, the kernel's default will be used.
814 <term><varname>IPv4RouteLocalnet=
</varname></term>
815 <listitem><para>Takes a boolean. When true, the kernel does not consider loopback addresses as martian source or destination
816 while routing. This enables the use of
127.0.0.0/
8 for local routing purposes. When unset, the kernel's default will be used.
820 <term><varname>IPv4ProxyARP=
</varname></term>
821 <listitem><para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one host,
822 usually a router, answers ARP requests intended for another machine. By
"faking" its identity,
823 the router accepts responsibility for routing packets to the
"real" destination. See
<ulink
824 url=
"https://tools.ietf.org/html/rfc1027">RFC
1027</ulink>.
825 When unset, the kernel's default will be used.
829 <term><varname>IPv6ProxyNDP=
</varname></term>
830 <listitem><para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery
831 Protocol) is a technique for IPv6 to allow routing of addresses to a different
832 destination when peers expect them to be present on a certain physical link.
833 In this case a router answers Neighbour Advertisement messages intended for
834 another machine by offering its own MAC address as destination.
835 Unlike proxy ARP for IPv4, it is not enabled globally, but will only send Neighbour
836 Advertisement messages for addresses in the IPv6 neighbor proxy table,
837 which can also be shown by
<command>ip -
6 neighbour show proxy
</command>.
838 systemd-networkd will control the per-interface `proxy_ndp` switch for each configured
839 interface depending on this option.
840 When unset, the kernel's default will be used.
844 <term><varname>IPv6ProxyNDPAddress=
</varname></term>
845 <listitem><para>An IPv6 address, for which Neighbour Advertisement messages will be
846 proxied. This option may be specified more than once. systemd-networkd will add the
847 <option>IPv6ProxyNDPAddress=
</option> entries to the kernel's IPv6 neighbor proxy table.
848 This option implies
<option>IPv6ProxyNDP=yes
</option> but has no effect if
849 <option>IPv6ProxyNDP
</option> has been set to false. When unset, the kernel's default will be used.
853 <term><varname>IPv6SendRA=
</varname></term>
854 <listitem><para>Whether to enable or disable Router Advertisement sending on a link. Takes a
855 boolean value. When enabled, prefixes configured in [IPv6Prefix] sections and routes
856 configured in [IPv6RoutePrefix] sections are distributed as defined in the [IPv6SendRA]
857 section. If
<varname>DHCPPrefixDelegation=
</varname> is enabled, then the delegated prefixes
858 are also distributed. See
<varname>DCHPPrefixDelegation=
</varname> setting and the
859 [IPv6SendRA], [IPv6Prefix], [IPv6RoutePrefix], and [DHCPPrefixDelegation] sections for more
860 configuration options.
</para></listitem>
863 <term><varname>DHCPPrefixDelegation=
</varname></term>
864 <listitem><para>Takes a boolean value. When enabled, requests subnet prefixes acquired by a
865 DHCPv6 client, or by a DHCPv4 client through the
6RD option configured on another link. By
866 default, an address within each delegated prefix will be assigned, and the prefixes will be
867 announced through IPv6 Router Advertisement when
<varname>IPv6SendRA=
</varname> is enabled.
868 Such default settings can be configured in [DHCPPrefixDelegation] section. Defaults to
869 disabled.
</para></listitem>
872 <term><varname>IPv6MTUBytes=
</varname></term>
873 <listitem><para>Configures IPv6 maximum transmission unit (MTU).
874 An integer greater than or equal to
1280 bytes. When unset, the kernel's default will be used.
878 <term><varname>KeepMaster=
</varname></term>
880 <para>Takes a boolean value. When enabled, the current master interface index will not be
881 changed, and
<varname>BatmanAdvanced=
</varname>,
<varname>Bond=
</varname>,
882 <varname>Bridge=
</varname>, and
<varname>VRF=
</varname> settings are ignored. This may be
883 useful when a netdev with a master interface is created by another program, e.g.
884 <citerefentry><refentrytitle>systemd-nspawn
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
885 Defaults to false.
</para>
889 <term><varname>BatmanAdvanced=
</varname></term>
890 <term><varname>Bond=
</varname></term>
891 <term><varname>Bridge=
</varname></term>
892 <term><varname>VRF=
</varname></term>
894 <para>The name of the B.A.T.M.A.N. Advanced, bond, bridge, or VRF interface to add the link
896 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
901 <term><varname>IPoIB=
</varname></term>
902 <term><varname>IPVLAN=
</varname></term>
903 <term><varname>IPVTAP=
</varname></term>
904 <term><varname>L2TP=
</varname></term>
905 <term><varname>MACsec=
</varname></term>
906 <term><varname>MACVLAN=
</varname></term>
907 <term><varname>MACVTAP=
</varname></term>
908 <term><varname>Tunnel=
</varname></term>
909 <term><varname>VLAN=
</varname></term>
910 <term><varname>VXLAN=
</varname></term>
911 <term><varname>Xfrm=
</varname></term>
913 <para>The name of an IPoIB, IPVLAN, IPVTAP, L2TP, MACsec, MACVLAN, MACVTAP, tunnel, VLAN,
914 VXLAN, or Xfrm to be created on the link. See
915 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
916 This option may be specified more than once.
</para>
920 <term><varname>ActiveSlave=
</varname></term>
922 <para>Takes a boolean. Specifies the new active slave. The
<literal>ActiveSlave=
</literal>
923 option is only valid for following modes:
924 <literal>active-backup
</literal>,
925 <literal>balance-alb
</literal> and
926 <literal>balance-tlb
</literal>. Defaults to false.
931 <term><varname>PrimarySlave=
</varname></term>
933 <para>Takes a boolean. Specifies which slave is the primary device. The specified
934 device will always be the active slave while it is available. Only when the
935 primary is off-line will alternate devices be used. This is useful when
936 one slave is preferred over another, e.g. when one slave has higher throughput
937 than another. The
<literal>PrimarySlave=
</literal> option is only valid for
939 <literal>active-backup
</literal>,
940 <literal>balance-alb
</literal> and
941 <literal>balance-tlb
</literal>. Defaults to false.
946 <term><varname>ConfigureWithoutCarrier=
</varname></term>
948 <para>Takes a boolean. Allows networkd to configure a specific link even if it has no carrier.
949 Defaults to false. If enabled, and the
<varname>IgnoreCarrierLoss=
</varname> setting is not
950 explicitly set, then it is enabled as well.
955 <term><varname>IgnoreCarrierLoss=
</varname></term>
957 <para>Takes a boolean or a timespan. When true, networkd retains both the static and dynamic
958 configuration of the interface even if its carrier is lost. When a timespan is specified,
959 networkd waits for the specified timespan, and ignores the carrier loss if the link regain
960 its carrier within the timespan. Setting a finite timespan may be useful for a wireless
961 interface connecting to a network which has multiple access points with the same SSID, or an
962 interface which is reset on changing MTU. When unset, the value specified with
963 <varname>ConfigureWithoutCarrier=
</varname> is used.
</para>
965 <para>When
<varname>ActivationPolicy=
</varname> is set to
<literal>always-up
</literal>, this
966 is forced to
<literal>true
</literal>.
971 <term><varname>KeepConfiguration=
</varname></term>
973 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
974 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
975 will not drop static addresses and routes on starting up process. When set to
976 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
977 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
978 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
979 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
980 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
981 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
982 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
<literal>no
</literal>.
990 <title>[Address] Section Options
</title>
992 <para>An [Address] section accepts the following keys. Specify several [Address]
993 sections to configure several addresses.
</para>
995 <variablelist class='network-directives'
>
997 <term><varname>Address=
</varname></term>
999 <para>As in the [Network] section. This key is mandatory. Each [Address] section can contain one
1000 <varname>Address=
</varname> setting.
</para>
1004 <term><varname>Peer=
</varname></term>
1006 <para>The peer address in a point-to-point connection.
1007 Accepts the same format as the
<varname>Address=
</varname>
1012 <term><varname>Broadcast=
</varname></term>
1014 <para>Takes an IPv4 address or boolean value. The address must be in the format described in
1015 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
1016 If set to true, then the IPv4 broadcast address will be derived from the
1017 <varname>Address=
</varname> setting. If set to false, then the broadcast address will not
1018 be set. Defaults to true, except for wireguard interfaces, where it default to false.
1023 <term><varname>Label=
</varname></term>
1025 <para>Specifies the label for the IPv4 address. The label must be a
7-bit ASCII string with
1026 a length of
1…
15 characters. Defaults to unset.
</para>
1030 <term><varname>PreferredLifetime=
</varname></term>
1032 <para>Allows the default
"preferred lifetime" of the address to be overridden. Only three
1033 settings are accepted:
<literal>forever
</literal>,
<literal>infinity
</literal>, which is the
1034 default and means that the address never expires, and
<literal>0</literal>, which means that the
1035 address is considered immediately
"expired" and will not be used, unless explicitly requested. A
1036 setting of
<option>PreferredLifetime=
0</option> is useful for addresses which are added to be
1037 used only by a specific application, which is then configured to use them explicitly.
</para>
1041 <term><varname>Scope=
</varname></term>
1043 <para>The scope of the address, which can be
1044 <literal>global
</literal> (valid everywhere on the network, even through a gateway),
1045 <literal>link
</literal> (only valid on this device, will not traverse a gateway) or
1046 <literal>host
</literal> (only valid within the device itself, e.g.
127.0.0.1)
1047 or an unsigned integer in the range
0…
255.
1048 Defaults to
<literal>global
</literal>.
</para>
1052 <term><varname>RouteMetric=
</varname></term>
1054 <para>The metric of the prefix route, which is pointing to the subnet of the configured IP
1055 address, taking the configured prefix length into account. Takes an unsigned integer in the
1056 range
0…
4294967295. When unset or set to
0, the kernel's default value is used. This
1057 setting will be ignored when
<varname>AddPrefixRoute=
</varname> is false.
</para>
1061 <term><varname>HomeAddress=
</varname></term>
1063 <para>Takes a boolean. Designates this address the
"home address" as defined in
1064 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>.
1065 Supported only on IPv6. Defaults to false.
</para>
1069 <term><varname>DuplicateAddressDetection=
</varname></term>
1071 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
1072 <literal>both
</literal>,
<literal>none
</literal>. When
<literal>ipv4
</literal>,
1073 performs IPv4 Address Conflict Detection. See
1074 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>.
1075 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
1076 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>.
1077 Defaults to
<literal>ipv6
</literal>.
</para>
1081 <term><varname>ManageTemporaryAddress=
</varname></term>
1083 <para>Takes a boolean. If true the kernel manage temporary addresses created
1084 from this one as template on behalf of Privacy Extensions
1085 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become
1086 active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
1087 The given address needs to have a prefix length of
64. This flag allows using privacy
1088 extensions in a manually configured network, just like if stateless auto-configuration
1089 was active. Defaults to false.
</para>
1093 <term><varname>AddPrefixRoute=
</varname></term>
1095 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
1096 Defaults to true.
</para>
1100 <term><varname>AutoJoin=
</varname></term>
1102 <para>Takes a boolean. Joining multicast group on ethernet level via
1103 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
1104 IGMP snooping since the switch would not replicate multicast packets on ports that did not
1105 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
1106 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
1107 that enables then to do the required join. By extending ip address command with option
1108 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
1109 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
1110 Defaults to
<literal>no
</literal>.
</para>
1117 <title>[Neighbor] Section Options
</title>
1118 <para>A [Neighbor] section accepts the following keys. The neighbor section adds a permanent, static
1119 entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the links
1120 matched for the network. Specify several [Neighbor] sections to configure several static neighbors.
1123 <variablelist class='network-directives'
>
1125 <term><varname>Address=
</varname></term>
1127 <para>The IP address of the neighbor.
</para>
1131 <term><varname>LinkLayerAddress=
</varname></term>
1133 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1140 <title>[IPv6AddressLabel] Section Options
</title>
1142 <para>An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel]
1143 sections to configure several address labels. IPv6 address labels are used for address selection. See
1144 <ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>. Precedence is managed by userspace,
1145 and only the label itself is stored in the kernel.
</para>
1147 <variablelist class='network-directives'
>
1149 <term><varname>Label=
</varname></term>
1151 <para>The label for the prefix, an unsigned integer in the range
0…
4294967294.
1152 0xffffffff is reserved. This setting is mandatory.
</para>
1156 <term><varname>Prefix=
</varname></term>
1158 <para>IPv6 prefix is an address with a prefix length, separated by a slash
<literal>/
</literal> character.
1159 This key is mandatory.
</para>
1166 <title>[RoutingPolicyRule] Section Options
</title>
1168 <para>An [RoutingPolicyRule] section accepts the following keys. Specify several [RoutingPolicyRule]
1169 sections to configure several rules.
</para>
1171 <variablelist class='network-directives'
>
1173 <term><varname>TypeOfService=
</varname></term>
1175 <para>Takes a number between
0 and
255 that specifies the type of service to match.
</para>
1179 <term><varname>From=
</varname></term>
1181 <para>Specifies the source address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1185 <term><varname>To=
</varname></term>
1187 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1191 <term><varname>FirewallMark=
</varname></term>
1193 <para>Specifies the iptables firewall mark value to match (a number between
1 and
1194 4294967295). Optionally, the firewall mask (also a number between
1 and
4294967295) can be
1195 suffixed with a slash (
<literal>/
</literal>), e.g.,
<literal>7/
255</literal>.
</para>
1199 <term><varname>Table=
</varname></term>
1201 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes one of predefined names
1202 <literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname>
1203 in
<citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1204 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1208 <term><varname>Priority=
</varname></term>
1210 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an unsigned
1211 integer in the range
0…
4294967295. Higher number means lower priority, and rules get
1212 processed in order of increasing number. Defaults to unset, and the kernel will pick
1213 a value dynamically.
</para>
1217 <term><varname>IncomingInterface=
</varname></term>
1219 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches packets originating from this host.
</para>
1223 <term><varname>OutgoingInterface=
</varname></term>
1225 <para>Specifies the outgoing device to match. The outgoing interface is only available for packets originating from local sockets that are bound to a device.
</para>
1229 <term><varname>SourcePort=
</varname></term>
1231 <para>Specifies the source IP port or IP port range match in forwarding information base (FIB) rules.
1232 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1236 <term><varname>DestinationPort=
</varname></term>
1238 <para>Specifies the destination IP port or IP port range match in forwarding information base (FIB) rules.
1239 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1243 <term><varname>IPProtocol=
</varname></term>
1245 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP protocol name such as
<literal>tcp
</literal>,
1246 <literal>udp
</literal> or
<literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
<literal>tcp
</literal> or
1247 <literal>17</literal> for
<literal>udp
</literal>.
1248 Defaults to unset.
</para>
1252 <term><varname>InvertRule=
</varname></term>
1254 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1258 <term><varname>Family=
</varname></term>
1260 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1261 <literal>both
</literal>. By default, the address family is determined by the address
1262 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1263 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1264 <literal>ipv4
</literal>.
</para>
1268 <term><varname>User=
</varname></term>
1270 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1275 <term><varname>SuppressPrefixLength=
</varname></term>
1277 <para>Takes a number
<replaceable>N
</replaceable> in the range
0…
128 and rejects routing
1278 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1283 <term><varname>SuppressInterfaceGroup=
</varname></term>
1285 <para>Takes an integer in the range
0…
2147483647 and rejects routing decisions that have
1286 an interface with the same group id. It has the same meaning as
1287 <option>suppress_ifgroup
</option> in
<command>ip rule
</command>. Defaults to unset.
</para>
1291 <term><varname>Type=
</varname></term>
1293 <para>Specifies Routing Policy Database (RPDB) rule type. Takes one of
<literal>blackhole
</literal>,
1294 <literal>unreachable
</literal> or
<literal>prohibit
</literal>.
1302 <title>[NextHop] Section Options
</title>
1303 <para>The [NextHop] section is used to manipulate entries in the kernel's
"nexthop" tables. The
1304 [NextHop] section accepts the following keys. Specify several [NextHop] sections to configure several
1307 <variablelist class='network-directives'
>
1309 <term><varname>Id=
</varname></term>
1311 <para>The id of the next hop. Takes an unsigned integer in the range
1…
4294967295. If left
1312 unspecified, then automatically chosen by kernel.
</para>
1316 <term><varname>Gateway=
</varname></term>
1318 <para>As in the [Network] section.
</para>
1322 <term><varname>Family=
</varname></term>
1324 <para>Takes one of the special values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>.
1325 By default, the family is determined by the address specified in
1326 <varname>Gateway=
</varname>. If
<varname>Gateway=
</varname> is not specified, then defaults
1327 to
<literal>ipv4
</literal>.
</para>
1331 <term><varname>OnLink=
</varname></term>
1333 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1334 reachable directly by the current machine (i.e., attached to the local network), so that we
1335 can insert the nexthop in the kernel table without it being complained about. Defaults to
1336 <literal>no
</literal>.
</para>
1340 <term><varname>Blackhole=
</varname></term>
1342 <para>Takes a boolean. If enabled, packets to the corresponding routes are discarded
1343 silently, and
<varname>Gateway=
</varname> cannot be specified. Defaults to
1344 <literal>no
</literal>.
</para>
1348 <term><varname>Group=
</varname></term>
1350 <para>Takes a whitespace separated list of nexthop IDs. Each ID must be in the range
1351 1…
4294967295. Optionally, each nexthop ID can take a weight after a colon
1352 (
<literal><replaceable>id
</replaceable><optional>:
<replaceable>weight
</replaceable></optional></literal>).
1353 The weight must be in the range
1…
255. If the weight is not specified, then it is assumed
1354 that the weight is
1. This setting cannot be specified with
<varname>Gateway=
</varname>,
1355 <varname>Family=
</varname>,
<varname>Blackhole=
</varname>. This setting can be specified
1356 multiple times. If an empty string is assigned, then the all previous assignments are
1357 cleared. Defaults to unset.
</para>
1364 <title>[Route] Section Options
</title>
1365 <para>The [Route] section accepts the following keys. Specify several [Route] sections to configure
1366 several routes.
</para>
1368 <variablelist class='network-directives'
>
1370 <term><varname>Gateway=
</varname></term>
1372 <para>Takes the gateway address or the special values
<literal>_dhcp4
</literal> and
1373 <literal>_ipv6ra
</literal>. If
<literal>_dhcp4
</literal> or
<literal>_ipv6ra
</literal> is
1374 set, then the gateway address provided by DHCPv4 or IPv6 RA is used.
</para>
1378 <term><varname>GatewayOnLink=
</varname></term>
1380 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1381 reachable directly by the current machine (i.e., attached to the local network), so that we
1382 can insert the route in the kernel table without it being complained about. Defaults to
1383 <literal>no
</literal>.
</para>
1387 <term><varname>Destination=
</varname></term>
1389 <para>The destination prefix of the route. Possibly
1390 followed by a slash and the prefix length. If omitted, a
1391 full-length host route is assumed.
</para>
1395 <term><varname>Source=
</varname></term>
1397 <para>The source prefix of the route. Possibly followed by
1398 a slash and the prefix length. If omitted, a full-length
1399 host route is assumed.
</para>
1403 <term><varname>Metric=
</varname></term>
1405 <para>The metric of the route. Takes an unsigned integer in the range
0…
4294967295.
1406 Defaults to unset, and the kernel's default will be used.
</para>
1410 <term><varname>IPv6Preference=
</varname></term>
1412 <para>Specifies the route preference as defined in
<ulink
1413 url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink> for Router Discovery messages. Which
1414 can be one of
<literal>low
</literal> the route has a lowest priority,
<literal>medium
</literal>
1415 the route has a default priority or
<literal>high
</literal> the route has a highest priority.
1420 <term><varname>Scope=
</varname></term>
1422 <para>The scope of the IPv4 route, which can be
<literal>global
</literal>,
<literal>site
</literal>,
1423 <literal>link
</literal>,
<literal>host
</literal>, or
1424 <literal>nowhere
</literal>:
</para>
1426 <listitem><para><literal>global
</literal> means the route can reach
1427 hosts more than one hop away.
</para></listitem>
1429 <listitem><para><literal>site
</literal> means an interior route in
1430 the local autonomous system.
</para></listitem>
1432 <listitem><para><literal>link
</literal> means the route can only
1433 reach hosts on the local network (one hop away).
</para></listitem>
1435 <listitem><para><literal>host
</literal> means the route will not
1436 leave the local machine (used for internal addresses like
1437 127.0.0.1).
</para></listitem>
1439 <listitem><para><literal>nowhere
</literal> means the destination
1440 doesn't exist.
</para></listitem>
1442 <para>For IPv4 route, defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
1443 <literal>local
</literal> or
<literal>nat
</literal>,
1444 and
<literal>link
</literal> if
<varname>Type=
</varname> is
1445 <literal>broadcast
</literal>,
<literal>multicast
</literal>, or
<literal>anycast
</literal>.
1446 In other cases, defaults to
<literal>global
</literal>. The value is
1447 not used for IPv6.
</para>
1451 <term><varname>PreferredSource=
</varname></term>
1453 <para>The preferred source address of the route. The address
1454 must be in the format described in
1455 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
1459 <term><varname>Table=
</varname></term>
1461 <para>The table identifier for the route. Takes one of predefined names
<literal>default
</literal>,
<literal>main
</literal>,
1462 and
<literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname> in
<citerefentry><refentrytitle>networkd.conf
</refentrytitle>
1463 <manvolnum>5</manvolnum></citerefentry>, or a number between
1 and
4294967295. The table can be retrieved using
1464 <command>ip route show table
<replaceable>num
</replaceable></command>. If unset and
<varname>Type=
</varname> is
<literal>local
</literal>,
1465 <literal>broadcast
</literal>,
<literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1466 In other cases, defaults to
<literal>main
</literal>.
1471 <term><varname>Protocol=
</varname></term>
1473 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special values
1474 <literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1475 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1480 <term><varname>Type=
</varname></term>
1482 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1483 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1484 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1485 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1486 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e. a
1487 route indicating the path to take to a destination network address. If
<literal>blackhole
</literal>, packets
1488 to the defined route are discarded silently. If
<literal>unreachable
</literal>, packets to the defined route
1489 are discarded and the ICMP message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets
1490 to the defined route are discarded and the ICMP message
"Communication Administratively Prohibited" is
1491 generated. If
<literal>throw
</literal>, route lookup in the current routing table will fail and the route
1492 selection process will return to Routing Policy Database (RPDB). Defaults to
<literal>unicast
</literal>.
1497 <term><varname>InitialCongestionWindow=
</varname></term>
1499 <para>The TCP initial congestion window is used during the start of a TCP connection.
1500 During the start of a TCP session, when a client requests a resource, the server's initial
1501 congestion window determines how many packets will be sent during the initial burst of data
1502 without waiting for acknowledgement. Takes a number between
1 and
1023. Note that
100 is
1503 considered an extremely large value for this option. When unset, the kernel's default
1504 (typically
10) will be used.
</para>
1508 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1510 <para>The TCP initial advertised receive window is the amount of receive data (in bytes)
1511 that can initially be buffered at one time on a connection. The sending host can send only
1512 that amount of data before waiting for an acknowledgment and window update from the
1513 receiving host. Takes a number between
1 and
1023. Note that
100 is considered an extremely
1514 large value for this option. When unset, the kernel's default will be used.
</para>
1518 <term><varname>QuickAck=
</varname></term>
1520 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the kernel's default will be used.
1525 <term><varname>FastOpenNoCookie=
</varname></term>
1527 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1528 When unset, the kernel's default will be used.
1533 <term><varname>TTLPropagate=
</varname></term>
1535 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1536 When unset, the kernel's default will be used.
1541 <term><varname>MTUBytes=
</varname></term>
1543 <para>The maximum transmission unit in bytes to set for the
1544 route. The usual suffixes K, M, G, are supported and are
1545 understood to the base of
1024.
</para>
1546 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
1547 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
1551 <term><varname>IPServiceType=
</varname></term>
1553 <para>Takes one of the special values
<literal>none
</literal>,
<literal>CS6
</literal>, or
1554 <literal>CS4
</literal>. When
<literal>none
</literal> no IP service type is set to the packet
1555 sent from the DHCPv4 client. When
<literal>CS6
</literal> (network control) or
1556 <literal>CS4
</literal> (realtime), the corresponding service type will be set. Defaults to
1557 <literal>CS6
</literal>.
</para>
1561 <term><varname>TCPAdvertisedMaximumSegmentSize=
</varname></term>
1563 <para>Specifies the Path MSS (in bytes) hints given on TCP layer. The usual suffixes K, M, G, are
1564 supported and are understood to the base of
1024. An unsigned integer in the range
1…
4294967294.
1565 When unset, the kernel's default will be used.
</para>
1569 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1571 <para>Configures multipath route. Multipath routing is the technique of using multiple
1572 alternative paths through a network. Takes gateway address. Optionally, takes a network
1573 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for
1574 this multipath route separated with whitespace. This setting can be specified multiple
1575 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
1579 <term><varname>NextHop=
</varname></term>
1581 <para>Specifies the nexthop id. Takes an unsigned integer in the range
1…
4294967295.
1582 If set, the corresponding [NextHop] section must be configured. Defaults to unset.
</para>
1589 <title>[DHCPv4] Section Options
</title>
1590 <para>The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the
1591 <varname>DHCP=
</varname> setting described above:
</para>
1593 <variablelist class='network-directives'
>
1595 <!-- DHCP packet contents -->
1598 <term><varname>SendHostname=
</varname></term>
1600 <para>When true (the default), the machine's hostname (or the value specified with
1601 <varname>Hostname=
</varname>, described below) will be sent to the DHCP server. Note that the
1602 hostname must consist only of
7-bit ASCII lower-case characters and no spaces or dots, and be
1603 formatted as a valid DNS domain name. Otherwise, the hostname is not sent even if this option is
1609 <term><varname>Hostname=
</varname></term>
1611 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's hostname.
1612 Note that the specified hostname must consist only of
7-bit ASCII lower-case characters and
1613 no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1618 <term><varname>MUDURL=
</varname></term>
1620 <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent to the
1621 DHCPv4 server. Takes a URL of length up to
255 characters. A superficial verification that the
1622 string is a valid URL will be performed. DHCPv4 clients are intended to have at most one MUD URL
1623 associated with them. See
<ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
1626 <para>MUD is an embedded software standard defined by the IETF that allows IoT device makers to
1627 advertise device specifications, including the intended communication patterns for their device
1628 when it connects to the network. The network can then use this to author a context-specific
1629 access policy, so the device functions only within those parameters.
</para>
1634 <term><varname>ClientIdentifier=
</varname></term>
1636 <para>The DHCPv4 client identifier to use. Takes one of
<option>mac
</option>,
1637 <option>duid
</option> or
<option>duid-only
</option>. If set to
<option>mac
</option>, the
1638 MAC address of the link is used. If set to
<option>duid
</option>, an RFC4361-compliant Client
1639 ID, which is the combination of IAID and DUID (see below), is used. If set to
1640 <option>duid-only
</option>, only DUID is used, this may not be RFC compliant, but some setups
1641 may require to use this. Defaults to
<option>duid
</option>.
</para>
1646 <term><varname>VendorClassIdentifier=
</varname></term>
1648 <para>The vendor class identifier used to identify vendor
1649 type and configuration.
</para>
1654 <term><varname>UserClass=
</varname></term>
1656 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or
1657 applications it represents. The information contained in this option is a string that represents
1658 the user class of which the client is a member. Each class sets an identifying string of
1659 information to be used by the DHCP service to classify clients. Takes a whitespace-separated list
1665 <term><varname>DUIDType=
</varname></term>
1667 <para>Override the global
<varname>DUIDType=
</varname> setting for this network. See
1668 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1669 for a description of possible values.
</para>
1674 <term><varname>DUIDRawData=
</varname></term>
1676 <para>Override the global
<varname>DUIDRawData=
</varname> setting for this network. See
1677 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1678 for a description of possible values.
</para>
1683 <term><varname>IAID=
</varname></term>
1685 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned
1691 <term><varname>Anonymize=
</varname></term>
1693 <para>Takes a boolean. When true, the options sent to the DHCP server will follow the
1694 <ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink> (Anonymity Profiles for
1695 DHCP Clients) to minimize disclosure of identifying information. Defaults to false.
</para>
1697 <para>This option should only be set to true when
<varname>MACAddressPolicy=
</varname> is
1698 set to
<option>random
</option> (see
1699 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
1702 <para>When true,
<varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1703 <varname>VendorClassIdentifier=
</varname>,
<varname>UserClass=
</varname>,
1704 <varname>RequestOptions=
</varname>,
<varname>SendOption=
</varname>,
1705 <varname>SendVendorOption=
</varname>, and
<varname>MUDURL=
</varname> are ignored.
</para>
1707 <para>With this option enabled DHCP requests will mimic those generated by Microsoft
1708 Windows, in order to reduce the ability to fingerprint and recognize installations. This
1709 means DHCP request sizes will grow and lease data will be more comprehensive than normally,
1710 though most of the requested data is not actually used.
</para>
1715 <term><varname>RequestOptions=
</varname></term>
1717 <para>Sets request options to be sent to the server in the DHCPv4 request options list. A
1718 whitespace-separated list of integers in the range
1…
254. Defaults to unset.
</para>
1723 <term><varname>SendOption=
</varname></term>
1725 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data type
1726 and data separated with a colon
1727 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1728 The option number must be an integer in the range
1…
254. The type takes one of
1729 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1730 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1731 string may be escaped using
<ulink
1732 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1733 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1734 then all options specified earlier are cleared. Defaults to unset.
</para>
1739 <term><varname>SendVendorOption=
</varname></term>
1741 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data
1742 type and data separated with a colon
1743 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1744 The option number must be an integer in the range
1…
254. The type takes one of
1745 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1746 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1747 string may be escaped using
<ulink
1748 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1749 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1750 then all options specified earlier are cleared. Defaults to unset.
</para>
1754 <!-- How to use the DHCP lease -->
1757 <term><varname>Label=
</varname></term>
1759 <para>Specifies the label for the IPv4 address received from the DHCP server.
1760 The label must be a
7-bit ASCII string with a length of
1…
15 characters.
1761 Defaults to unset.
</para>
1766 <term><varname>UseDNS=
</varname></term>
1768 <para>When true (the default), the DNS servers received from the DHCP server will be used.
</para>
1770 <para>This corresponds to the
<option>nameserver
</option>
1771 option in
<citerefentry
1772 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1777 <term><varname>RoutesToDNS=
</varname></term>
1779 <para>When true, the routes to the DNS servers received from the DHCP server will be
1780 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored.
1781 Defaults to true.
</para>
1786 <term><varname>UseNTP=
</varname></term>
1788 <para>When true (the default), the NTP servers received from the DHCP server will be used by
1789 <filename>systemd-timesyncd.service
</filename>.
</para>
1794 <term><varname>RoutesToNTP=
</varname></term>
1796 <para>When true, the routes to the NTP servers received from the DHCP server will be
1797 configured. When
<varname>UseNTP=
</varname> is disabled, this setting is ignored.
1798 Defaults to true.
</para>
1803 <term><varname>UseSIP=
</varname></term>
1805 <para>When true (the default), the SIP servers received from the DHCP server will be collected
1806 and made available to client programs.
</para>
1811 <term><varname>UseMTU=
</varname></term>
1813 <para>When true, the interface maximum transmission unit from the DHCP server will be used on the
1814 current link. If
<varname>MTUBytes=
</varname> is set, then this setting is ignored. Defaults to
1816 <para>Note, some drivers will reset the interfaces if the MTU is changed. For such
1817 interfaces, please try to use
<varname>IgnoreCarrierLoss=
</varname> with a short timespan,
1818 e.g.
<literal>3 seconds
</literal>.
</para>
1823 <term><varname>UseHostname=
</varname></term>
1825 <para>When true (the default), the hostname received from the DHCP server will be set as the
1826 transient hostname of the system.
</para>
1831 <term><varname>UseDomains=
</varname></term>
1833 <para>Takes a boolean, or the special value
<option>route
</option>. When true, the domain name
1834 received from the DHCP server will be used as DNS search domain over this link, similar to the
1835 effect of the
<option>Domains=
</option> setting. If set to
<option>route
</option>, the domain
1836 name received from the DHCP server will be used for routing DNS queries only, but not for
1837 searching, similar to the effect of the
<option>Domains=
</option> setting when the argument is
1838 prefixed with
<literal>~
</literal>. Defaults to false.
</para>
1840 <para>It is recommended to enable this option only on trusted networks, as setting this affects
1841 resolution of all hostnames, in particular of single-label names. It is generally safer to use
1842 the supplied domain only as routing domain, rather than as search domain, in order to not have it
1843 affect local resolution of single-label names.
</para>
1845 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
1846 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1852 <term><varname>UseRoutes=
</varname></term>
1854 <para>When true (the default), the static routes will be requested from the DHCP server and added
1855 to the routing table with a metric of
1024, and a scope of
<option>global
</option>,
1856 <option>link
</option> or
<option>host
</option>, depending on the route's destination and
1857 gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the link's own
1858 address, the scope will be set to
<option>host
</option>. Otherwise if the gateway is null (a
1859 direct route), a
<option>link
</option> scope will be used. For anything else, scope defaults to
1860 <option>global
</option>.
</para>
1865 <term><varname>RouteMetric=
</varname></term>
1867 <para>Set the routing metric for routes specified by the DHCP server (including the prefix
1868 route added for the specified prefix). Takes an unsigned integer in the range
0…
4294967295.
1869 Defaults to
1024.
</para>
1874 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1876 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to unset).
1877 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1879 <para>When used in combination with
<varname>VRF=
</varname>, the
1880 VRF's routing table is used when this parameter is not specified.
1886 <term><varname>RouteMTUBytes=
</varname></term>
1888 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further details.
</para>
1893 <term><varname>UseGateway=
</varname></term>
1895 <para>When true, the gateway will be requested from the DHCP server and added to the routing
1896 table with a metric of
1024, and a scope of
<option>link
</option>. When unset, the value specified
1897 with
<varname>UseRoutes=
</varname> is used.
</para>
1902 <term><varname>UseTimezone=
</varname></term>
1903 <listitem><para>When true, the timezone received from the DHCP server will be set as timezone of
1904 the local system. Defaults to false.
</para></listitem>
1908 <term><varname>Use6RD=
</varname></term>
1909 <listitem><para>When true, subnets of the received IPv6 prefix are assigned to downstream
1910 interfaces which enables
<varname>DHCPPrefixDelegation=
</varname>. See also
1911 <varname>DHCPPrefixDelegation=
</varname> in the [Network] section, the [DHCPPrefixDelegation]
1912 section, and
<ulink url=
"https://tools.ietf.org/html/rfc5969">RFC
5969</ulink>. Defaults to
1913 false.
</para></listitem>
1917 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
1919 <para>Allows to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease lifetime.
1920 Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal>. The latter means that the
1921 address never expires. Defaults to unset.
</para>
1925 <!-- How to communicate with the server -->
1928 <term><varname>RequestBroadcast=
</varname></term>
1930 <para>Request the server to use broadcast messages before the IP address has been configured.
1931 This is necessary for devices that cannot receive RAW packets, or that cannot receive packets at
1932 all before an IP address has been configured. On the other hand, this must not be enabled on
1933 networks where broadcasts are filtered out.
</para>
1938 <term><varname>MaxAttempts=
</varname></term>
1940 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
1941 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>. Note that the
1942 time between retries is increased exponentially, up to approximately one per minute, so the
1943 network will not be overloaded even if this number is high. The default is suitable in most
1944 circumstances.
</para>
1949 <term><varname>ListenPort=
</varname></term>
1951 <para>Set the port from which the DHCP client packets originate.
</para>
1956 <term><varname>DenyList=
</varname></term>
1958 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
1959 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are
1960 rejected. Note that if
<varname>AllowList=
</varname> is configured then
1961 <varname>DenyList=
</varname> is ignored.
</para>
1966 <term><varname>AllowList=
</varname></term>
1968 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
1969 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are
1975 <term><varname>SendRelease=
</varname></term>
1977 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops. Defaults to
1983 <term><varname>SendDecline=
</varname></term>
1985 <para>A boolean. When
<literal>true
</literal>, the DHCPv4 client receives the IP address from the
1986 DHCP server. After a new IP is received, the DHCPv4 client performs IPv4 Duplicate Address
1987 Detection. If duplicate use is detected, the DHCPv4 client rejects the IP by sending a
1988 <constant>DHCPDECLINE
</constant> packet and tries to obtain an IP address again. See
<ulink
1989 url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>. Defaults to
1990 <literal>unset
</literal>.
</para>
1998 <title>[DHCPv6] Section Options
</title>
1999 <para>The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the
2000 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
</para>
2002 <variablelist class='network-directives'
>
2004 <!-- DHCP packet contents -->
2007 <term><varname>MUDURL=
</varname></term>
2008 <term><varname>IAID=
</varname></term>
2009 <term><varname>DUIDType=
</varname></term>
2010 <term><varname>DUIDRawData=
</varname></term>
2011 <term><varname>RequestOptions=
</varname></term>
2013 <para>As in the [DHCPv4] section.
</para>
2018 <term><varname>SendOption=
</varname></term>
2020 <para>As in the [DHCPv4] section, however because DHCPv6 uses
16-bit fields to store option
2021 numbers, the option number is an integer in the range
1…
65536.
</para>
2026 <term><varname>SendVendorOption=
</varname></term>
2028 <para>Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier, DHCP
2029 option number, data type, and data separated with a colon (
<literal><replaceable>enterprise
2030 identifier
</replaceable>:
<replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2031 Enterprise identifier is an unsigned integer in the range
1…
4294967294. The option number must be
2032 an integer in the range
1…
254. Data type takes one of
<literal>uint8
</literal>,
2033 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
2034 <literal>ipv6address
</literal>, or
<literal>string
</literal>. Special characters in the data
2035 string may be escaped using
<ulink
2036 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2037 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2038 then all options specified earlier are cleared. Defaults to unset.
</para>
2043 <term><varname>UserClass=
</varname></term>
2045 <para>A DHCPv6 client can use User Class option to identify the type or category of user or
2046 applications it represents. The information contained in this option is a string that represents
2047 the user class of which the client is a member. Each class sets an identifying string of
2048 information to be used by the DHCP service to classify clients. Special characters in the data
2049 string may be escaped using
<ulink
2050 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2051 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2052 then all options specified earlier are cleared. Takes a whitespace-separated list of
2053 strings. Note that currently
<constant>NUL
</constant> bytes are not allowed.
</para>
2058 <term><varname>VendorClass=
</varname></term>
2060 <para>A DHCPv6 client can use VendorClass option to identify the vendor that manufactured the
2061 hardware on which the client is running. The information contained in the data area of this
2062 option is contained in one or more opaque fields that identify details of the hardware
2063 configuration. Takes a whitespace-separated list of strings.
</para>
2068 <term><varname>PrefixDelegationHint=
</varname></term>
2070 <para>Takes an IPv6 address with prefix length in the same format as the
2071 <varname>Address=
</varname> in the [Network] section. The DHCPv6 client will include a prefix
2072 hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range
2073 1…
128. Defaults to unset.
</para>
2077 <!-- How to use the DHCP lease -->
2080 <term><varname>UseAddress=
</varname></term>
2082 <para>When true (the default), the IP addresses provided by the DHCPv6 server will be
2088 <term><varname>UseDelegatedPrefix=
</varname></term>
2090 <para>When true (the default), the client will request the DHCPv6 server to delegate
2091 prefixes. If the server provides prefixes to be delegated, then subnets of the prefixes are
2092 assigned to the interfaces which enables
<varname>DHCPPrefixDelegation=
</varname>.
2093 See also
<varname>DHCPPrefixDelegation=
</varname> in [Network] section,
2094 [DHCPPrefixDelegation] section, and
2095 <ulink url=
"https://www.rfc-editor.org/rfc/rfc8415.html#section-6.3">RFC
8415</ulink>.
2101 <term><varname>UseDNS=
</varname></term>
2102 <term><varname>UseNTP=
</varname></term>
2103 <term><varname>UseHostname=
</varname></term>
2104 <term><varname>UseDomains=
</varname></term>
2106 <para>As in the [DHCPv4] section.
</para>
2110 <!-- How to communicate with the server -->
2113 <term><varname>WithoutRA=
</varname></term>
2115 <para>Allows DHCPv6 client to start without router advertisements's managed or other
2116 address configuration flag. Takes one of
<literal>no
</literal>,
<literal>solicit
</literal>
2117 or
<literal>information-request
</literal>. If this is not specified,
2118 <literal>solicit
</literal> is used when
<varname>DHCPPrefixDelegation=
</varname> is
2119 enabled and
<varname>UplinkInterface=:self
</varname> is specified in the
2120 [DHCPPrefixDelegation] section. Otherwise, defaults to
<literal>no
</literal>, and the
2121 DHCPv6 client will be started when an RA is received. See also
2122 <varname>DHCPv6Client=
</varname> setting in the [IPv6AcceptRA] section.
</para>
2129 <title>[DHCPPrefixDelegation] Section Options
</title>
2130 <para>The [DHCPPrefixDelegation] section configures subnet prefixes of the delegated prefixes
2131 acquired by a DHCPv6 client, or by a DHCPv4 client through the
6RD option on another interface.
2132 The settings in this section are used only when the
<varname>DHCPPrefixDelegation=
</varname>
2133 setting in the [Network] section is enabled.
</para>
2135 <variablelist class='network-directives'
>
2137 <term><varname>UplinkInterface=
</varname></term>
2139 <para>Specifies the name or the index of the uplink interface, or one of the special values
2140 <literal>:self
</literal> and
<literal>:auto
</literal>. When
<literal>:self
</literal>, the
2141 interface itself is considered the uplink interface, and
2142 <varname>WithoutRA=solicit
</varname> is implied if the setting is not explicitly specified.
2143 When
<literal>:auto
</literal>, the first link which acquired prefixes to be delegated from
2144 the DHCPv6 or DHCPv4 server is selected. Defaults to
<literal>:auto
</literal>.
</para>
2149 <term><varname>SubnetId=
</varname></term>
2151 <para>Configure a specific subnet ID on the interface from a (previously) received prefix
2152 delegation. You can either set
"auto" (the default) or a specific subnet ID (as defined in
2153 <ulink url=
"https://tools.ietf.org/html/rfc4291#section-2.5.4">RFC
4291</ulink>, section
2154 2.5.4), in which case the allowed value is hexadecimal, from
0 to
0x7fffffffffffffff
2160 <term><varname>Announce=
</varname></term>
2162 <para>Takes a boolean. When enabled, and
<varname>IPv6SendRA=
</varname> in [Network] section
2163 is enabled, the delegated prefixes are distributed through the IPv6 Router Advertisement.
2164 This setting will be ignored when the
<varname>DHCPPrefixDelegation=
</varname> setting is
2165 enabled on the upstream interface. Defaults to yes.
</para>
2170 <term><varname>Assign=
</varname></term>
2172 <para>Takes a boolean. Specifies whether to add an address from the delegated prefixes which
2173 are received from the WAN interface by the DHCPv6 Prefix Delegation. When true (on LAN
2174 interfce), the EUI-
64 algorithm will be used by default to form an interface identifier from
2175 the delegated prefixes. See also
<varname>Token=
</varname> setting below. Defaults to yes.
2181 <term><varname>Token=
</varname></term>
2183 <para>Specifies an optional address generation mode for assigning an address in each
2184 delegated prefix. This accepts the same syntax as
<varname>Token=
</varname> in the
2185 [IPv6AcceptRA] section. If
<varname>Assign=
</varname> is set to false, then this setting will
2186 be ignored. Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2191 <term><varname>ManageTemporaryAddress=
</varname></term>
2193 <para>As in the [Address] section, but defaults to true.
</para>
2198 <term><varname>RouteMetric=
</varname></term>
2200 <para>The metric of the route to the delegated prefix subnet. Takes an unsigned integer in
2201 the range
0…
4294967295. When set to
0, the kernel's default value is used. Defaults to
256.
2209 <title>[IPv6AcceptRA] Section Options
</title>
2210 <para>The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled
2211 with the
<varname>IPv6AcceptRA=
</varname> setting described above:
</para>
2213 <variablelist class='network-directives'
>
2215 <term><varname>Token=
</varname></term>
2217 <para>Specifies an optional address generation mode for the Stateless Address
2218 Autoconfiguration (SLAAC). The following values are supported:
</para>
2222 <term><option>eui64
</option></term>
2225 The EUI-
64 algorithm will be used to generate an address for that prefix. Only
2226 supported by Ethernet or InfiniBand interfaces.
2231 <term><option>static:
<replaceable>ADDRESS
</replaceable></option></term>
2234 An IPv6 address must be specified after a colon (
<literal>:
</literal>), and the
2235 lower bits of the supplied address are combined with the upper bits of a prefix
2236 received in a Router Advertisement (RA) message to form a complete address. Note
2237 that if multiple prefixes are received in an RA message, or in multiple RA messages,
2238 addresses will be formed from each of them using the supplied address. This mode
2239 implements SLAAC but uses a static interface identifier instead of an identifier
2240 generated by using the EUI-
64 algorithm. Because the interface identifier is static,
2241 if Duplicate Address Detection detects that the computed address is a duplicate
2242 (in use by another node on the link), then this mode will fail to provide an address
2243 for that prefix. If an IPv6 address without mode is specified, then
2244 <literal>static
</literal> mode is assumed.
2249 <term><option>prefixstable[:
<replaceable>ADDRESS
</replaceable>][,
<replaceable>UUID
</replaceable>]
</option></term>
2252 The algorithm specified in
2253 <ulink url=
"https://tools.ietf.org/html/rfc7217">RFC
7217</ulink> will be used to
2254 generate interface identifiers. This mode can optionally take an IPv6 address
2255 separated with a colon (
<literal>:
</literal>). If an IPv6 address is specified,
2256 then an interface identifier is generated only when a prefix received in an RA
2257 message matches the supplied address.
2260 This mode can also optionally take a non-null UUID in the format which
2261 <function>sd_id128_from_string()
</function> accepts, e.g.
2262 <literal>86b123b969ba4b7eb8b3d8605123525a
</literal> or
2263 <literal>86b123b9-
69ba-
4b7e-b8b3-d8605123525a
</literal>. If a UUID is specified, the
2264 value is used as the secret key to generate interface identifiers. If not specified,
2265 then an application specific ID generated with the system's machine-ID will be used
2266 as the secret key. See
2267 <citerefentry><refentrytitle>sd-id128
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2268 <citerefentry><refentrytitle>sd_id128_from_string
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2270 <citerefentry><refentrytitle>sd_id128_get_machine
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2273 Note that the
<literal>prefixstable
</literal> algorithm uses both the interface
2274 name and MAC address as input to the hash to compute the interface identifier, so
2275 if either of those are changed the resulting interface identifier (and address)
2276 will be changed, even if the prefix received in the RA message has not been
2283 <para>If no address generation mode is specified (which is the default), or a received
2284 prefix does not match any of the addresses provided in
<literal>prefixstable
</literal>
2285 mode, then the EUI-
64 algorithm will be used for Ethernet or InfiniBand interfaces,
2286 otherwise
<literal>prefixstable
</literal> will be used to form an interface identifier for
2289 <para>This setting can be specified multiple times. If an empty string is assigned, then
2290 the all previous assignments are cleared.
</para>
2293 <programlisting>Token=eui64
2295 Token=static:::
1a:
2b:
3c:
4d
2297 Token=prefixstable:
2002:da8:
1::
</programlisting></para>
2302 <term><varname>UseDNS=
</varname></term>
2304 <para>When true (the default), the DNS servers received in the Router Advertisement will be used.
</para>
2306 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
2307 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2312 <term><varname>UseDomains=
</varname></term>
2314 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
2315 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
2316 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
2317 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
2318 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
2319 <literal>~
</literal>. Defaults to false.
</para>
2321 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
2322 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
2323 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
2324 single-label names.
</para>
2326 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
2327 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2332 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
2334 <para>The table identifier for the routes received in the Router Advertisement
2335 (a number between
1 and
4294967295, or
0 to unset).
2336 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
2342 <term><varname>RouteMetric=
</varname></term>
2344 <para>Set the routing metric for the routes received in the Router Advertisement. Takes an
2345 unsigned integer in the range
0…
4294967295. Defaults to
1024.
</para>
2350 <term><varname>UseMTU=
</varname></term>
2352 <para>Takes a boolean. When true, the MTU received in the Router Advertisement will be
2353 used. Defaults to true.
</para>
2358 <term><varname>UseGateway=
</varname></term>
2360 <para>When true (the default), the router address will be configured as the default gateway.
2366 <term><varname>UseRoutePrefix=
</varname></term>
2368 <para>When true (the default), the routes corresponding to the route prefixes received in
2369 the Router Advertisement will be configured.
</para>
2374 <term><varname>UseAutonomousPrefix=
</varname></term>
2376 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
2377 precedence over any statically configured ones.
</para>
2382 <term><varname>UseOnLinkPrefix=
</varname></term>
2384 <para>When true (the default), the onlink prefix received in the Router Advertisement will be
2385 used and takes precedence over any statically configured ones.
</para>
2390 <term><varname>RouterDenyList=
</varname></term>
2392 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2393 take a prefix length after
<literal>/
</literal>. Any information advertised by the listed
2394 router is ignored.
</para>
2399 <term><varname>RouterAllowList=
</varname></term>
2401 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2402 take a prefix length after
<literal>/
</literal>. Only information advertised by the listed
2403 router is accepted. Note that if
<varname>RouterAllowList=
</varname> is configured then
2404 <varname>RouterDenyList=
</varname> is ignored.
</para>
2409 <term><varname>PrefixDenyList=
</varname></term>
2411 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2412 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2413 in the list are ignored.
</para>
2418 <term><varname>PrefixAllowList=
</varname></term>
2420 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2421 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2422 in the list are allowed. Note that if
<varname>PrefixAllowList=
</varname> is configured
2423 then
<varname>PrefixDenyList=
</varname> is ignored.
</para>
2428 <term><varname>RouteDenyList=
</varname></term>
2430 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2431 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2432 advertisements in the list are ignored.
</para>
2437 <term><varname>RouteAllowList=
</varname></term>
2439 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2440 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2441 advertisements in the list are allowed. Note that if
<varname>RouteAllowList=
</varname> is
2442 configured then
<varname>RouteDenyList=
</varname> is ignored.
</para>
2447 <term><varname>DHCPv6Client=
</varname></term>
2449 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true, the
2450 DHCPv6 client will be started when the RA has the managed or other information flag. If set
2451 to
<literal>always
</literal>, the DHCPv6 client will be started in managed mode when an RA
2452 is received, even if neither managed nor other information flag is set in the RA. This will
2453 be ignored when
<varname>WithoutRA=
</varname> in the [DHCPv6] section is enabled, or
2454 <varname>UplinkInterface=:self
</varname> in the [DHCPPrefixDelegation] section is
2455 specified. Defaults to true.
</para>
2462 <title>[DHCPServer] Section Options
</title>
2463 <para>The [DHCPServer] section contains settings for the DHCP server, if enabled via the
2464 <varname>DHCPServer=
</varname> option described above:
</para>
2466 <variablelist class='network-directives'
>
2469 <term><varname>ServerAddress=
</varname></term>
2470 <listitem><para>Specifies server address for the DHCP server. Takes an IPv4 address with prefix
2471 length, for example
<literal>192.168.0.1/
24</literal>. This setting may be useful when the link on
2472 which the DHCP server is running has multiple static addresses. When unset, one of static addresses
2473 in the link will be automatically selected. Defaults to unset.
</para></listitem>
2477 <term><varname>PoolOffset=
</varname></term>
2478 <term><varname>PoolSize=
</varname></term>
2480 <listitem><para>Configures the pool of addresses to hand out. The pool
2481 is a contiguous sequence of IP addresses in the subnet configured for
2482 the server address, which does not include the subnet nor the broadcast
2483 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
2484 from the start of subnet, or zero to use the default value.
2485 <varname>PoolSize=
</varname> takes the number of IP addresses in the
2486 pool or zero to use the default value. By default, the pool starts at
2487 the first address after the subnet address and takes up the rest of
2488 the subnet, excluding the broadcast address. If the pool includes
2489 the server address (the default), this is reserved and not handed
2490 out to clients.
</para></listitem>
2494 <term><varname>DefaultLeaseTimeSec=
</varname></term>
2495 <term><varname>MaxLeaseTimeSec=
</varname></term>
2497 <listitem><para>Control the default and maximum DHCP lease
2498 time to pass to clients. These settings take time values in seconds or
2499 another common time unit, depending on the suffix. The default
2500 lease time is used for clients that did not ask for a specific
2501 lease time. If a client asks for a lease time longer than the
2502 maximum lease time, it is automatically shortened to the
2503 specified time. The default lease time defaults to
1h, the
2504 maximum lease time to
12h. Shorter lease times are beneficial
2505 if the configuration data in DHCP leases changes frequently
2506 and clients shall learn the new settings with shorter
2507 latencies. Longer lease times reduce the generated DHCP
2508 network traffic.
</para></listitem>
2512 <term><varname>UplinkInterface=
</varname></term>
2513 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2514 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS, NTP, or SIP
2515 servers is enabled but no servers are specified, the servers configured in the uplink interface
2516 will be emitted. When
<literal>:auto
</literal>, the link which has a default gateway with the
2517 highest priority will be automatically selected. When
<literal>:none
</literal>, no uplink
2518 interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2522 <term><varname>EmitDNS=
</varname></term>
2523 <term><varname>DNS=
</varname></term>
2525 <listitem><para><varname>EmitDNS=
</varname> takes a boolean. Configures whether the DHCP leases
2526 handed out to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>. The
2527 DNS servers to pass to clients may be configured with the
<varname>DNS=
</varname> option, which takes
2528 a list of IPv4 addresses. If the
<varname>EmitDNS=
</varname> option is enabled but no servers
2529 configured, the servers are automatically propagated from an
"uplink" interface that has appropriate
2530 servers set. The
"uplink" interface is determined by the default route of the system with the highest
2531 priority. Note that this information is acquired at the time the lease is handed out, and does not
2532 take uplink interfaces into account that acquire DNS server information at a later point. If no
2533 suitable uplink interface is found the DNS server data from
<filename>/etc/resolv.conf
</filename> is
2534 used. Also, note that the leases are not refreshed if the uplink network configuration changes. To
2535 ensure clients regularly acquire the most current uplink DNS server information, it is thus advisable
2536 to shorten the DHCP lease time via
<varname>MaxLeaseTimeSec=
</varname> described
2537 above.
</para></listitem>
2541 <term><varname>EmitNTP=
</varname></term>
2542 <term><varname>NTP=
</varname></term>
2543 <term><varname>EmitSIP=
</varname></term>
2544 <term><varname>SIP=
</varname></term>
2545 <term><varname>EmitPOP3=
</varname></term>
2546 <term><varname>POP3=
</varname></term>
2547 <term><varname>EmitSMTP=
</varname></term>
2548 <term><varname>SMTP=
</varname></term>
2549 <term><varname>EmitLPR=
</varname></term>
2550 <term><varname>LPR=
</varname></term>
2552 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname> settings
2553 described above, these settings configure whether and what server information for the indicate
2554 protocol shall be emitted as part of the DHCP lease. The same syntax, propagation semantics and
2555 defaults apply as for
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname>.
</para></listitem>
2559 <term><varname>EmitRouter=
</varname></term>
2560 <term><varname>Router=
</varname></term>
2562 <listitem><para>The
<varname>EmitRouter=
</varname> setting takes a boolean value, and configures
2563 whether the DHCP lease should contain the router option. The
<varname>Router=
</varname> setting
2564 takes an IPv4 address, and configures the router address to be emitted. When the
2565 <varname>Router=
</varname> setting is not specified, then the server address will be used for
2566 the router option. When the
<varname>EmitRouter=
</varname> setting is disabled, the
2567 <varname>Router=
</varname> setting will be ignored. The
<varname>EmitRouter=
</varname> setting
2568 defaults to true, and the
<varname>Router=
</varname> setting defaults to unset.
2573 <term><varname>EmitTimezone=
</varname></term>
2574 <term><varname>Timezone=
</varname></term>
2576 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2577 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2578 <varname>Timezone=
</varname> setting takes a timezone string
2579 (such as
<literal>Europe/Berlin
</literal> or
2580 <literal>UTC
</literal>) to pass to clients. If no explicit
2581 timezone is set, the system timezone of the local host is
2582 propagated, as determined by the
2583 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2587 <term><varname>SendOption=
</varname></term>
2589 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2590 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2591 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2592 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2593 <literal>string
</literal>. Special characters in the data string may be escaped using
2594 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2595 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2596 then all options specified earlier are cleared. Defaults to unset.
</para>
2601 <term><varname>SendVendorOption=
</varname></term>
2603 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2604 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2605 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2606 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2607 <literal>string
</literal>. Special characters in the data string may be escaped using
2608 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2609 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2610 then all options specified earlier are cleared. Defaults to unset.
</para>
2614 <term><varname>BindToInterface=
</varname></term>
2616 <para>Takes a boolean value. When
<literal>yes
</literal>, DHCP server socket will be bound
2617 to its network interface and all socket communication will be restricted to this interface.
2618 Defaults to
<literal>yes
</literal>, except if
<varname>RelayTarget=
</varname> is used (see below),
2619 in which case it defaults to
<literal>no
</literal>.
</para>
2623 <term><varname>RelayTarget=
</varname></term>
2625 <para>Takes an IPv4 address, which must be in the format described in
2626 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
2627 Turns this DHCP server into a DHCP relay agent. See
<ulink url=
"https://tools.ietf.org/html/rfc1542">RFC
1542</ulink>.
2628 The address is the address of DHCP server or another relay agent to forward DHCP messages to and from.
</para>
2632 <term><varname>RelayAgentCircuitId=
</varname></term>
2634 <para>Specifies value for Agent Circuit ID suboption of Relay Agent Information option.
2635 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2636 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2637 Defaults to unset (means no Agent Circuit ID suboption is generated).
2638 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2642 <term><varname>RelayAgentRemoteId=
</varname></term>
2644 <para>Specifies value for Agent Remote ID suboption of Relay Agent Information option.
2645 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2646 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2647 Defaults to unset (means no Agent Remote ID suboption is generated).
2648 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2656 <title>[DHCPServerStaticLease] Section Options
</title>
2657 <para>The
<literal>[DHCPServerStaticLease]
</literal> section configures a static DHCP lease to assign a
2658 fixed IPv4 address to a specific device based on its MAC address. This section can be specified multiple
2661 <variablelist class='network-directives'
>
2663 <term><varname>MACAddress=
</varname></term>
2665 <listitem><para>The hardware address of a device to match. This key is mandatory.
</para></listitem>
2669 <term><varname>Address=
</varname></term>
2671 <listitem><para>The IPv4 address that should be assigned to the device that was matched with
2672 <varname>MACAddress=
</varname>. This key is mandatory.
</para></listitem>
2678 <title>[IPv6SendRA] Section Options
</title>
2679 <para>The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether
2680 to act as a router, if enabled via the
<varname>IPv6SendRA=
</varname> option described above. IPv6
2681 network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections.
2684 <variablelist class='network-directives'
>
2687 <term><varname>Managed=
</varname></term>
2688 <term><varname>OtherInformation=
</varname></term>
2690 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2691 addresses on the network link when
<varname>Managed=
</varname>
2692 is set to
<literal>true
</literal> or if only additional network
2693 information can be obtained via DHCPv6 for the network link when
2694 <varname>OtherInformation=
</varname> is set to
2695 <literal>true
</literal>. Both settings default to
2696 <literal>false
</literal>, which means that a DHCPv6 server is not being
2697 used.
</para></listitem>
2701 <term><varname>RouterLifetimeSec=
</varname></term>
2703 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. The value must be
0
2704 seconds, or between
4 seconds and
9000 seconds. When set to
0, the host is not acting as a router.
2705 Defaults to
1800 seconds (
30 minutes).
</para>
2710 <term><varname>RouterPreference=
</varname></term>
2712 <listitem><para>Configures IPv6 router preference if
2713 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2714 <literal>high
</literal>,
<literal>medium
</literal> and
2715 <literal>low
</literal>, with
<literal>normal
</literal> and
2716 <literal>default
</literal> added as synonyms for
2717 <literal>medium
</literal> just to make configuration easier. See
2718 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2719 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2723 <term><varname>UplinkInterface=
</varname></term>
2724 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2725 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS servers or
2726 search domains is enabled but no servers are specified, the servers configured in the uplink
2727 interface will be emitted. When
<literal>:auto
</literal>, the value specified to the same
2728 setting in the [DHCPPrefixDelegation] section will be used if
2729 <varname>DHCPPrefixDelegation=
</varname> is enabled, otherwise the link which has a default
2730 gateway with the highest priority will be automatically selected. When
<literal>:none
</literal>,
2731 no uplink interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2735 <term><varname>EmitDNS=
</varname></term>
2736 <term><varname>DNS=
</varname></term>
2738 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses
2739 that are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is true.
2740 <varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that case
2741 the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS servers are
2742 read from the [Network] section. If the [Network] section does not contain any DNS servers
2743 either, DNS servers from the uplink interface specified in
<varname>UplinkInterface=
</varname>
2744 will be used. When
<varname>EmitDNS=
</varname> is false, no DNS server information is sent in
2745 Router Advertisement messages.
<varname>EmitDNS=
</varname> defaults to true.
</para></listitem>
2749 <term><varname>EmitDomains=
</varname></term>
2750 <term><varname>Domains=
</varname></term>
2752 <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when
2753 <varname>EmitDomains=
</varname> is true. If
<varname>Domains=
</varname> is empty, DNS search
2754 domains are read from the [Network] section. If the [Network] section does not contain any DNS
2755 search domains either, DNS search domains from the uplink interface specified in
2756 <varname>UplinkInterface=
</varname> will be used. When
<varname>EmitDomains=
</varname> is false,
2757 no DNS search domain information is sent in Router Advertisement messages.
2758 <varname>EmitDomains=
</varname> defaults to true.
</para></listitem>
2762 <term><varname>DNSLifetimeSec=
</varname></term>
2764 <listitem><para>Lifetime in seconds for the DNS server addresses listed in
2765 <varname>DNS=
</varname> and search domains listed in
<varname>Domains=
</varname>. Defaults to
2766 3600 seconds (one hour).
</para></listitem>
2773 <title>[IPv6Prefix] Section Options
</title>
2774 <para>One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router
2775 Advertisements. See
<ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink> for further
2778 <variablelist class='network-directives'
>
2781 <term><varname>AddressAutoconfiguration=
</varname></term>
2782 <term><varname>OnLink=
</varname></term>
2784 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2785 autoconfigured with this prefix and whether the prefix can be used for
2786 onlink determination. Both settings default to
<literal>true
</literal>
2787 in order to ease configuration.
2792 <term><varname>Prefix=
</varname></term>
2794 <listitem><para>The IPv6 prefix that is to be distributed to hosts. Similarly to configuring static
2795 IPv6 addresses, the setting is configured as an IPv6 prefix and its prefix length, separated by a
2796 <literal>/
</literal> character. Use multiple [IPv6Prefix] sections to configure multiple IPv6
2797 prefixes since prefix lifetimes, address autoconfiguration and onlink status may differ from one
2798 prefix to another.
</para></listitem>
2802 <term><varname>PreferredLifetimeSec=
</varname></term>
2803 <term><varname>ValidLifetimeSec=
</varname></term>
2805 <listitem><para>Preferred and valid lifetimes for the prefix measured in seconds.
2806 <varname>PreferredLifetimeSec=
</varname> defaults to
1800 seconds (
30 minutes) and
2807 <varname>ValidLifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2811 <term><varname>Assign=
</varname></term>
2812 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2817 <term><varname>Token=
</varname></term>
2819 <para>Specifies an optional address generation mode for assigning an address in each
2820 prefix. This accepts the same syntax as
<varname>Token=
</varname> in the [IPv6AcceptRA]
2821 section. If
<varname>Assign=
</varname> is set to false, then this setting will be ignored.
2822 Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2827 <term><varname>RouteMetric=
</varname></term>
2829 <para>The metric of the prefix route. Takes an unsigned integer in the range
0…
4294967295.
2830 When unset or set to
0, the kernel's default value is used. This setting is ignored when
2831 <varname>Assign=
</varname> is false.
</para>
2838 <title>[IPv6RoutePrefix] Section Options
</title>
2839 <para>One or more [IPv6RoutePrefix] sections contain the IPv6
2840 prefix routes that are announced via Router Advertisements. See
2841 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2842 for further details.
</para>
2844 <variablelist class='network-directives'
>
2847 <term><varname>Route=
</varname></term>
2849 <listitem><para>The IPv6 route that is to be distributed to hosts. Similarly to configuring static
2850 IPv6 routes, the setting is configured as an IPv6 prefix routes and its prefix route length,
2851 separated by a
<literal>/
</literal> character. Use multiple [IPv6PrefixRoutes] sections to configure
2852 multiple IPv6 prefix routes.
</para></listitem>
2856 <term><varname>LifetimeSec=
</varname></term>
2858 <listitem><para>Lifetime for the route prefix measured in seconds.
2859 <varname>LifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2866 <title>[Bridge] Section Options
</title>
2867 <para>The [Bridge] section accepts the following keys:
</para>
2868 <variablelist class='network-directives'
>
2870 <term><varname>UnicastFlood=
</varname></term>
2872 <para>Takes a boolean. Controls whether the bridge should flood
2873 traffic for which an FDB entry is missing and the destination
2874 is unknown through this port. When unset, the kernel's default will be used.
2879 <term><varname>MulticastFlood=
</varname></term>
2881 <para>Takes a boolean. Controls whether the bridge should flood
2882 traffic for which an MDB entry is missing and the destination
2883 is unknown through this port. When unset, the kernel's default will be used.
2888 <term><varname>MulticastToUnicast=
</varname></term>
2890 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
2891 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
2892 When unset, the kernel's default will be used.
2897 <term><varname>NeighborSuppression=
</varname></term>
2899 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
2900 this port. When unset, the kernel's default will be used.
2905 <term><varname>Learning=
</varname></term>
2907 <para>Takes a boolean. Configures whether MAC address learning is enabled for
2908 this port. When unset, the kernel's default will be used.
2913 <term><varname>HairPin=
</varname></term>
2915 <para>Takes a boolean. Configures whether traffic may be sent back out of the port on which it
2916 was received. When this flag is false, then the bridge will not forward traffic back out of the
2917 receiving port. When unset, the kernel's default will be used.
</para>
2921 <term><varname>UseBPDU=
</varname></term>
2923 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
2924 processed by the bridge port. When unset, the kernel's default will be used.
</para>
2928 <term><varname>FastLeave=
</varname></term>
2930 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
2931 traffic on a port that receives an IGMP Leave message. It is only used with
2932 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
2936 <term><varname>AllowPortToBeRoot=
</varname></term>
2938 <para>Takes a boolean. Configures whether a given port is allowed to
2939 become a root port. Only used when STP is enabled on the bridge.
2940 When unset, the kernel's default will be used.
</para>
2944 <term><varname>ProxyARP=
</varname></term>
2946 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
2947 When unset, the kernel's default will be used.
</para>
2951 <term><varname>ProxyARPWiFi=
</varname></term>
2953 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
2954 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
2955 When unset, the kernel's default will be used.
</para>
2959 <term><varname>MulticastRouter=
</varname></term>
2961 <para>Configures this port for having multicast routers attached. A port with a multicast
2962 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
2963 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
2964 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
2965 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
2966 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
2970 <term><varname>Cost=
</varname></term>
2972 <para>Sets the
"cost" of sending packets of this interface.
2973 Each port in a bridge may have a different speed and the cost
2974 is used to decide which link to use. Faster interfaces
2975 should have lower costs. It is an integer value between
1 and
2980 <term><varname>Priority=
</varname></term>
2982 <para>Sets the
"priority" of sending packets on this interface.
2983 Each port in a bridge may have a different priority which is used
2984 to decide which link to use. Lower value means higher priority.
2985 It is an integer value between
0 to
63. Networkd does not set any
2986 default, meaning the kernel default value of
32 is used.
</para>
2992 <title>[BridgeFDB] Section Options
</title>
2993 <para>The [BridgeFDB] section manages the forwarding database table of a port and accepts the following
2994 keys. Specify several [BridgeFDB] sections to configure several static MAC table entries.
</para>
2996 <variablelist class='network-directives'
>
2998 <term><varname>MACAddress=
</varname></term>
3000 <para>As in the [Network] section. This key is mandatory.
</para>
3004 <term><varname>Destination=
</varname></term>
3006 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
3010 <term><varname>VLANId=
</varname></term>
3012 <para>The VLAN ID for the new static MAC table entry. If
3013 omitted, no VLAN ID information is appended to the new static MAC
3018 <term><varname>VNI=
</varname></term>
3020 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
3021 the remote VXLAN tunnel endpoint. Takes a number in the range
1…
16777215.
3022 Defaults to unset.
</para>
3026 <term><varname>AssociatedWith=
</varname></term>
3028 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
3029 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
3030 <literal>use
</literal> means the address is in use. User space can use this option to
3031 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
3032 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
3033 means the address is associated with master devices fdb.
<literal>router
</literal> means
3034 the destination address is associated with a router. Note that it's valid if the referenced
3035 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
3039 <term><varname>OutgoingInterface=
</varname></term>
3041 <para>Specifies the name or index of the outgoing interface for the VXLAN device driver to
3042 reach the remote VXLAN tunnel endpoint. Defaults to unset.
</para>
3048 <title>[BridgeMDB] Section Options
</title>
3049 <para>The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following
3050 keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.
</para>
3052 <variablelist class='network-directives'
>
3054 <term><varname>MulticastGroupAddress=
</varname></term>
3056 <para>Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.
</para>
3060 <term><varname>VLANId=
</varname></term>
3062 <para>The VLAN ID for the new entry. Valid ranges are
0 (no VLAN) to
4094. Optional, defaults to
0.
</para>
3069 <title>[LLDP] Section Options
</title>
3070 <para>The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following
3072 <variablelist class='network-directives'
>
3074 <term><varname>MUDURL=
</varname></term>
3076 <para>When configured, the specified Manufacturer Usage Descriptions (MUD) URL will be sent in
3077 LLDP packets. The syntax and semantics are the same as for
<varname>MUDURL=
</varname> in the
3078 [DHCPv4] section described above.
</para>
3080 <para>The MUD URLs received via LLDP packets are saved and can be read using the
3081 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
3088 <title>[CAN] Section Options
</title>
3089 <para>The [CAN] section manages the Controller Area Network (CAN bus) and accepts the
3090 following keys:
</para>
3091 <variablelist class='network-directives'
>
3093 <term><varname>BitRate=
</varname></term>
3095 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
3096 be used here. Takes a number in the range
1…
4294967295.
</para>
3100 <term><varname>SamplePoint=
</varname></term>
3102 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
3103 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>). This will be ignored when
3104 <varname>BitRate=
</varname> is unspecified.
</para>
3108 <term><varname>TimeQuantaNSec=
</varname></term>
3109 <term><varname>PropagationSegment=
</varname></term>
3110 <term><varname>PhaseBufferSegment1=
</varname></term>
3111 <term><varname>PhaseBufferSegment2=
</varname></term>
3112 <term><varname>SyncJumpWidth=
</varname></term>
3114 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3115 synchronization jump width, which allow to define the CAN bit-timing in a hardware
3116 independent format as proposed by the Bosch CAN
2.0 Specification.
3117 <varname>TimeQuantaNSec=
</varname> takes a timespan in nanoseconds.
3118 <varname>PropagationSegment=
</varname>,
<varname>PhaseBufferSegment1=
</varname>,
3119 <varname>PhaseBufferSegment2=
</varname>, and
<varname>SyncJumpWidth=
</varname> take number
3120 of time quantum specified in
<varname>TimeQuantaNSec=
</varname> and must be an unsigned
3121 integer in the range
0…
4294967295. These settings except for
3122 <varname>SyncJumpWidth=
</varname> will be ignored when
<varname>BitRate=
</varname> is
3127 <term><varname>DataBitRate=
</varname></term>
3128 <term><varname>DataSamplePoint=
</varname></term>
3130 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
3131 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
3135 <term><varname>DataTimeQuantaNSec=
</varname></term>
3136 <term><varname>DataPropagationSegment=
</varname></term>
3137 <term><varname>DataPhaseBufferSegment1=
</varname></term>
3138 <term><varname>DataPhaseBufferSegment2=
</varname></term>
3139 <term><varname>DataSyncJumpWidth=
</varname></term>
3141 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3142 synchronization jump width for the data phase, if CAN-FD is used. These settings are
3143 analogous to the
<varname>TimeQuantaNSec=
</varname> or related settings.
</para>
3147 <term><varname>FDMode=
</varname></term>
3149 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
3150 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
3151 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys, or
3152 <varname>DataTimeQuanta=
</varname> and related settings.
</para>
3156 <term><varname>FDNonISO=
</varname></term>
3158 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
3159 interface. When unset, the kernel's default will be used.
</para>
3163 <term><varname>RestartSec=
</varname></term>
3165 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
3166 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
3167 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
3168 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
3169 automatic restart off. By default automatic restart is disabled.
</para>
3173 <term><varname>Termination=
</varname></term>
3175 <para>Takes a boolean or a termination resistor value in ohm in the range
0…
65535. When
3176 <literal>yes
</literal>, the termination resistor is set to
120 ohm. When
3177 <literal>no
</literal> or
<literal>0</literal> is set, the termination resistor is disabled.
3178 When unset, the kernel's default will be used.
</para>
3182 <term><varname>TripleSampling=
</varname></term>
3184 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
3185 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
3189 <term><varname>BusErrorReporting=
</varname></term>
3191 <para>Takes a boolean. When
<literal>yes
</literal>, reporting of CAN bus errors is activated
3192 (those include single bit, frame format, and bit stuffing errors, unable to send dominant bit,
3193 unable to send recessive bit, bus overload, active error announcement, error occurred on
3194 transmission). When unset, the kernel's default will be used. Note: in case of a CAN bus with a
3195 single CAN device, sending a CAN frame may result in a huge number of CAN bus errors.
</para>
3199 <term><varname>ListenOnly=
</varname></term>
3201 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
3202 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
3203 bit. Listen-only mode is important to debug CAN networks without interfering with the
3204 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
3209 <term><varname>Loopback=
</varname></term>
3211 <para>Takes a boolean. When
<literal>yes
</literal>, loopback mode is enabled. When the
3212 loopback mode is enabled, the interface treats messages transmitted by itself as received
3213 messages. The loopback mode is important to debug CAN networks. When unset, the kernel's
3214 default will be used.
</para>
3218 <term><varname>OneShot=
</varname></term>
3220 <para>Takes a boolean. When
<literal>yes
</literal>, one-shot mode is enabled. When unset,
3221 the kernel's default will be used.
</para>
3225 <term><varname>PresumeAck=
</varname></term>
3227 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will ignore missing CAN
3228 ACKs. When unset, the kernel's default will be used.
</para>
3232 <term><varname>ClassicDataLengthCode=
</varname></term>
3234 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will handle the
4bit data
3235 length code (DLC). When unset, the kernel's default will be used.
</para>
3242 <title>[IPoIB] Section Options
</title>
3243 <para>The [IPoIB] section manages the IP over Infiniband and accepts the following keys:
</para>
3244 <variablelist class='network-directives'
>
3245 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_mode" />
3246 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_umcast" />
3251 <title>[QDisc] Section Options
</title>
3252 <para>The [QDisc] section manages the traffic control queueing discipline (qdisc).
</para>
3254 <variablelist class='network-directives'
>
3256 <term><varname>Parent=
</varname></term>
3258 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
3259 or
<literal>ingress
</literal>. This is mandatory.
</para>
3263 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3268 <title>[NetworkEmulator] Section Options
</title>
3269 <para>The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It
3270 can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP
3271 applications, or limit the bandwidth usage of a particular service to simulate internet connections.
3274 <variablelist class='network-directives'
>
3275 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3276 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3279 <term><varname>DelaySec=
</varname></term>
3281 <para>Specifies the fixed amount of delay to be added to all packets going out of the
3282 interface. Defaults to unset.
</para>
3287 <term><varname>DelayJitterSec=
</varname></term>
3289 <para>Specifies the chosen delay to be added to the packets outgoing to the network
3290 interface. Defaults to unset.
</para>
3295 <term><varname>PacketLimit=
</varname></term>
3297 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
3298 An unsigned integer in the range
0…
4294967294. Defaults to
1000.
</para>
3303 <term><varname>LossRate=
</varname></term>
3305 <para>Specifies an independent loss probability to be added to the packets outgoing from the
3306 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3311 <term><varname>DuplicateRate=
</varname></term>
3313 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
3314 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3321 <title>[TokenBucketFilter] Section Options
</title>
3322 <para>The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter
3325 <variablelist class='network-directives'
>
3326 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3327 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3330 <term><varname>LatencySec=
</varname></term>
3332 <para>Specifies the latency parameter, which specifies the maximum amount of time a
3333 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
3338 <term><varname>LimitBytes=
</varname></term>
3340 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
3341 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
3342 respectively, to the base of
1024. Defaults to unset.
</para>
3347 <term><varname>BurstBytes=
</varname></term>
3349 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
3350 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
3351 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to
3357 <term><varname>Rate=
</varname></term>
3359 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
3360 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
3361 Defaults to unset.
</para>
3366 <term><varname>MPUBytes=
</varname></term>
3368 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
3369 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3370 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to zero.
</para>
3375 <term><varname>PeakRate=
</varname></term>
3377 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
3378 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3379 1000. Defaults to unset.
</para>
3384 <term><varname>MTUBytes=
</varname></term>
3386 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
3387 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
3388 Defaults to unset.
</para>
3395 <title>[PIE] Section Options
</title>
3396 <para>The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral
3397 controller-Enhanced (PIE).
</para>
3399 <variablelist class='network-directives'
>
3400 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3401 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3404 <term><varname>PacketLimit=
</varname></term>
3406 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3407 incoming packets are dropped. An unsigned integer in the range
1…
4294967294. Defaults to unset and
3408 kernel's default is used.
</para>
3415 <title>[FlowQueuePIE] Section Options
</title>
3416 <para>The
<literal>[FlowQueuePIE]
</literal> section manages the queueing discipline
3417 (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).
</para>
3419 <variablelist class='network-directives'
>
3420 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3421 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3424 <term><varname>PacketLimit=
</varname></term>
3426 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3427 incoming packets are dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and
3428 kernel's default is used.
</para>
3435 <title>[StochasticFairBlue] Section Options
</title>
3436 <para>The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue
3439 <variablelist class='network-directives'
>
3440 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3441 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3444 <term><varname>PacketLimit=
</varname></term>
3446 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3447 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3448 kernel's default is used.
</para>
3455 <title>[StochasticFairnessQueueing] Section Options
</title>
3456 <para>The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic
3457 fairness queueing (sfq).
</para>
3459 <variablelist class='network-directives'
>
3460 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3461 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3464 <term><varname>PerturbPeriodSec=
</varname></term>
3466 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
3473 <title>[BFIFO] Section Options
</title>
3474 <para>The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First
3477 <variablelist class='network-directives'
>
3478 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3479 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3482 <term><varname>LimitBytes=
</varname></term>
3484 <para>Specifies the hard limit in bytes on the FIFO buffer size. The size limit prevents overflow
3485 in case the kernel is unable to dequeue packets as quickly as it receives them. When this limit is
3486 reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed
3487 as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3488 kernel default is used.
</para>
3495 <title>[PFIFO] Section Options
</title>
3496 <para>The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out
3499 <variablelist class='network-directives'
>
3500 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3501 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3504 <term><varname>PacketLimit=
</varname></term>
3506 <para>Specifies the hard limit on the number of packets in the FIFO queue. The size limit prevents
3507 overflow in case the kernel is unable to dequeue packets as quickly as it receives them. When this
3508 limit is reached, incoming packets are dropped. An unsigned integer in the range
3509 0…
4294967294. Defaults to unset and kernel's default is used.
</para>
3516 <title>[PFIFOHeadDrop] Section Options
</title>
3517 <para>The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out
3518 Head Drop (pfifo_head_drop).
</para>
3520 <variablelist class='network-directives'
>
3521 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3522 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3525 <term><varname>PacketLimit=
</varname></term>
3527 <para>As in [PFIFO] section.
</para></listitem>
3533 <title>[PFIFOFast] Section Options
</title>
3534 <para>The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast
3535 (pfifo_fast).
</para>
3537 <variablelist class='network-directives'
>
3538 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3539 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3544 <title>[CAKE] Section Options
</title>
3545 <para>The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced
3548 <variablelist class='network-directives'
>
3549 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3550 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3553 <term><varname>Bandwidth=
</varname></term>
3555 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
3556 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
3557 unset and kernel's default is used.
</para>
3562 <term><varname>AutoRateIngress=
</varname></term>
3564 <para>Takes a boolean value. Enables automatic capacity estimation based on traffic arriving
3565 at this qdisc. This is most likely to be useful with cellular links, which tend to change
3566 quality randomly. If this setting is enabled, the
<varname>Bandwidth=
</varname> setting is
3567 used as an initial estimate. Defaults to unset, and the kernel's default is used.
</para>
3572 <term><varname>OverheadBytes=
</varname></term>
3574 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative.
3575 Takes an integer in the range -
64…
256. Defaults to unset and kernel's default is used.
3581 <term><varname>MPUBytes=
</varname></term>
3583 <para>Rounds each packet (including overhead) up to the specified bytes. Takes an integer in
3584 the range
1…
256. Defaults to unset and kernel's default is used.
</para>
3589 <term><varname>CompensationMode=
</varname></term>
3591 <para>Takes one of
<literal>none
</literal>,
<literal>atm
</literal>, or
<literal>ptm
</literal>.
3592 Specifies the compensation mode for overhead calculation. When
<literal>none
</literal>, no
3593 compensation is taken into account. When
<literal>atm
</literal>, enables the compensation for
3594 ATM cell framing, which is normally found on ADSL links. When
<literal>ptm
</literal>, enables
3595 the compensation for PTM encoding, which is normally found on VDSL2 links and uses a
64b/
65b
3596 encoding scheme. Defaults to unset and the kernel's default is used.
</para>
3601 <term><varname>UseRawPacketSize=
</varname></term>
3603 <para>Takes a boolean value. When true, the packet size reported by the Linux kernel will be
3604 used, instead of the underlying IP packet size. Defaults to unset, and the kernel's default
3610 <term><varname>FlowIsolationMode=
</varname></term>
3612 <para>CAKE places packets from different flows into different queues, then packets from each
3613 queue are delivered fairly. This specifies whether the fairness is based on source address,
3614 destination address, individual flows, or any combination of those. The available values are:
3619 <term><option>none
</option></term>
3621 The flow isolation is disabled, and all traffic passes through a single queue.
3625 <term><option>src-host
</option></term>
3627 Flows are defined only by source address. Equivalnet to the
<literal>srchost
</literal>
3628 option for
<command>tc qdisc
</command> command. See also
3629 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3633 <term><option>dst-host
</option></term>
3635 Flows are defined only by destination address. Equivalnet to the
3636 <literal>srchost
</literal> option for
<command>tc qdisc
</command> command. See also
3637 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3641 <term><option>hosts
</option></term>
3643 Flows are defined by source-destination host pairs. Equivalent to the same option for
3644 <command>tc qdisc
</command> command. See also
3645 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3649 <term><option>flows
</option></term>
3651 Flows are defined by the entire
5-tuple of source address, destination address,
3652 transport protocol, source port and destination port. Equivalent to the same option for
3653 <command>tc qdisc
</command> command. See also
3654 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3658 <term><option>dual-src-host
</option></term>
3660 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3661 fairness is applied first over source addresses, then over individual flows. Equivalnet
3662 to the
<literal>dual-srchost
</literal> option for
<command>tc qdisc
</command> command.
3664 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3668 <term><option>dual-dst-host
</option></term>
3670 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3671 fairness is applied first over destination addresses, then over individual flows.
3672 Equivalnet to the
<literal>dual-dsthost
</literal> option for
3673 <command>tc qdisc
</command> command. See also
3674 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3678 <term><option>triple
</option></term>
3680 Flows are defined by the
5-tuple (see
<literal>flows
</literal>), and fairness is
3681 applied over source and destination addresses, and also over individual flows.
3682 Equivalnet to the
<literal>triple-isolate
</literal> option for
3683 <command>tc qdisc
</command> command. See also
3684 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3689 <para>Defaults to unset and the kernel's default is used.
</para>
3694 <term><varname>NAT=
</varname></term>
3696 <para>Takes a boolean value. When true, CAKE performs a NAT lookup before applying
3697 flow-isolation rules, to determine the true addresses and port numbers of the packet, to
3698 improve fairness between hosts inside the NAT. This has no practical effect when
3699 <varname>FlowIsolationMode=
</varname> is
<literal>none
</literal> or
<literal>flows
</literal>,
3700 or if NAT is performed on a different host. Defaults to unset, and the kernel's default is
3706 <term><varname>PriorityQueueingPreset=
</varname></term>
3708 <para>CAKE divides traffic into
<literal>tins
</literal>, and each tin has its own independent
3709 set of flow-isolation queues, bandwidth threshold, and priority. This specifies the preset of
3710 tin profiles. The available values are:
</para>
3714 <term><option>besteffort
</option></term>
3716 Disables priority queueing by placing all traffic in one tin.
3720 <term><option>precedence
</option></term>
3722 Enables priority queueing based on the legacy interpretation of TOS
3723 <literal>Precedence
</literal> field. Use of this preset on the modern Internet is
3728 <term><option>diffserv8
</option></term>
3730 Enables priority queueing based on the Differentiated Service
3731 (
<literal>DiffServ
</literal>) field with eight tins: Background Traffic, High
3732 Throughput, Best Effort, Video Streaming, Low Latency Transactions, Interactive Shell,
3733 Minimum Latency, and Network Control.
3737 <term><option>diffserv4
</option></term>
3739 Enables priority queueing based on the Differentiated Service
3740 (
<literal>DiffServ
</literal>) field with four tins: Background Traffic, Best Effort,
3741 Streaming Media, and Latency Sensitive.
3745 <term><option>diffserv3
</option></term>
3747 Enables priority queueing based on the Differentiated Service
3748 (
<literal>DiffServ
</literal>) field with three tins: Background Traffic, Best Effort,
3749 and Latency Sensitive.
3754 <para>Defaults to unset, and the kernel's default is used.
</para>
3759 <term><varname>FirewallMark=
</varname></term>
3761 <para>Takes an integer in the range
1…
4294967295. When specified, firewall-mark-based
3762 overriding of CAKE's tin selection is enabled. Defaults to unset, and the kernel's default is
3768 <term><varname>Wash=
</varname></term>
3770 <para>Takes a boolean value. When true, CAKE clears the DSCP fields, except for ECN bits, of
3771 any packet passing through CAKE. Defaults to unset, and the kernel's default is used.
</para>
3776 <term><varname>SplitGSO=
</varname></term>
3778 <para>Takes a boolean value. When true, CAKE will split General Segmentation Offload (GSO)
3779 super-packets into their on-the-wire components and dequeue them individually. Defaults to
3780 unset, and the kernel's default is used.
</para>
3788 <title>[ControlledDelay] Section Options
</title>
3789 <para>The [ControlledDelay] section manages the queueing discipline (qdisc) of
3790 controlled delay (CoDel).
</para>
3792 <variablelist class='network-directives'
>
3793 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3794 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3797 <term><varname>PacketLimit=
</varname></term>
3799 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3800 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3801 kernel's default is used.
</para>
3806 <term><varname>TargetSec=
</varname></term>
3808 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3809 Defaults to unset and kernel's default is used.
</para>
3814 <term><varname>IntervalSec=
</varname></term>
3816 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3817 become too stale. Defaults to unset and kernel's default is used.
</para>
3822 <term><varname>ECN=
</varname></term>
3824 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3825 unset and kernel's default is used.
</para>
3830 <term><varname>CEThresholdSec=
</varname></term>
3832 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3833 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3840 <title>[DeficitRoundRobinScheduler] Section Options
</title>
3841 <para>The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round
3842 Robin Scheduler (DRR).
</para>
3844 <variablelist class='network-directives'
>
3845 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3846 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3851 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
3852 <para>The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round
3853 Robin Scheduler (DRR).
</para>
3855 <variablelist class='network-directives'
>
3856 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3857 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3860 <term><varname>QuantumBytes=
</varname></term>
3862 <para>Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves
3863 to the next class. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3864 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to the MTU of the
3873 <title>[EnhancedTransmissionSelection] Section Options
</title>
3874 <para>The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced
3875 Transmission Selection (ETS).
</para>
3877 <variablelist class='network-directives'
>
3878 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3879 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3882 <term><varname>Bands=
</varname></term>
3884 <para>Specifies the number of bands. An unsigned integer in the range
1…
16. This value has to be at
3885 least large enough to cover the strict bands specified through the
<varname>StrictBands=
</varname>
3886 and bandwidth-sharing bands specified in
<varname>QuantumBytes=
</varname>.
</para>
3891 <term><varname>StrictBands=
</varname></term>
3893 <para>Specifies the number of bands that should be created in strict mode. An unsigned integer in
3894 the range
1…
16.
</para>
3899 <term><varname>QuantumBytes=
</varname></term>
3901 <para>Specifies the white-space separated list of quantum used in band-sharing bands. When
3902 suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3903 respectively, to the base of
1024. This setting can be specified multiple times. If an empty
3904 string is assigned, then the all previous assignments are cleared.
</para>
3909 <term><varname>PriorityMap=
</varname></term>
3911 <para>The priority map maps the priority of a packet to a band. The argument is a whitespace
3912 separated list of numbers. The first number indicates which band the packets with priority
0 should
3913 be put to, the second is for priority
1, and so on. There can be up to
16 numbers in the list. If
3914 there are fewer, the default band that traffic with one of the unmentioned priorities goes to is
3915 the last one. Each band number must be in the range
0…
255. This setting can be specified multiple
3916 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
3923 <title>[GenericRandomEarlyDetection] Section Options
</title>
3924 <para>The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random
3925 Early Detection (GRED).
</para>
3927 <variablelist class='network-directives'
>
3928 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3929 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3932 <term><varname>VirtualQueues=
</varname></term>
3934 <para>Specifies the number of virtual queues. Takes an integer in the range
1…
16. Defaults to unset
3935 and kernel's default is used.
</para>
3940 <term><varname>DefaultVirtualQueue=
</varname></term>
3942 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
3943 Defaults to unset and kernel's default is used.
</para>
3948 <term><varname>GenericRIO=
</varname></term>
3950 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
3951 unset and kernel's default is used.
</para>
3958 <title>[FairQueueingControlledDelay] Section Options
</title>
3959 <para>The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing
3960 controlled delay (FQ-CoDel).
</para>
3962 <variablelist class='network-directives'
>
3963 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3964 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3967 <term><varname>PacketLimit=
</varname></term>
3969 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
3970 dropped. Defaults to unset and kernel's default is used.
</para>
3975 <term><varname>MemoryLimitBytes=
</varname></term>
3977 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
3978 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3979 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
3984 <term><varname>Flows=
</varname></term>
3986 <para>Specifies the number of flows into which the incoming packets are classified.
3987 Defaults to unset and kernel's default is used.
</para>
3992 <term><varname>TargetSec=
</varname></term>
3994 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3995 Defaults to unset and kernel's default is used.
</para>
4000 <term><varname>IntervalSec=
</varname></term>
4002 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
4003 become too stale. Defaults to unset and kernel's default is used.
</para>
4008 <term><varname>QuantumBytes=
</varname></term>
4010 <para>Specifies the number of bytes used as the
"deficit" in the fair queuing algorithm timespan.
4011 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4012 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
4017 <term><varname>ECN=
</varname></term>
4019 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
4020 unset and kernel's default is used.
</para>
4025 <term><varname>CEThresholdSec=
</varname></term>
4027 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4028 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4035 <title>[FairQueueing] Section Options
</title>
4036 <para>The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing
4039 <variablelist class='network-directives'
>
4040 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4041 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4044 <term><varname>PacketLimit=
</varname></term>
4046 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
4047 dropped. Defaults to unset and kernel's default is used.
</para>
4052 <term><varname>FlowLimit=
</varname></term>
4054 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
4055 unset and kernel's default is used.
</para>
4060 <term><varname>QuantumBytes=
</varname></term>
4062 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
4063 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4064 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
4065 default is used.
</para>
4070 <term><varname>InitialQuantumBytes=
</varname></term>
4072 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
4073 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
4074 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
4075 kernel's default is used.
</para>
4080 <term><varname>MaximumRate=
</varname></term>
4082 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
4083 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
4084 1000. Defaults to unset and kernel's default is used.
</para>
4089 <term><varname>Buckets=
</varname></term>
4091 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
4092 kernel's default is used.
</para>
4097 <term><varname>OrphanMask=
</varname></term>
4099 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
4100 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
4101 kernel's default is used.
</para>
4106 <term><varname>Pacing=
</varname></term>
4108 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
4109 default is used.
</para>
4114 <term><varname>CEThresholdSec=
</varname></term>
4116 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4117 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4124 <title>[TrivialLinkEqualizer] Section Options
</title>
4125 <para>The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link
4126 equalizer (teql).
</para>
4128 <variablelist class='network-directives'
>
4129 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4130 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4133 <term><varname>Id=
</varname></term>
4135 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
4136 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
4137 <constant>max_equalizers=N+
1</constant> option must be loaded before
4138 <command>systemd-networkd
</command> is started.
</para>
4145 <title>[HierarchyTokenBucket] Section Options
</title>
4146 <para>The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token
4147 bucket (htb).
</para>
4149 <variablelist class='network-directives'
>
4150 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4151 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4154 <term><varname>DefaultClass=
</varname></term>
4156 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
4157 to the class. Defaults to unset.
</para>
4162 <term><varname>RateToQuantum=
</varname></term>
4164 <para>Takes an unsigned integer. The DRR quantums are calculated by dividing the value
4165 configured in
<varname>Rate=
</varname> by
<varname>RateToQuantum=
</varname>.
</para>
4172 <title>[HierarchyTokenBucketClass] Section Options
</title>
4173 <para>The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket
4176 <variablelist class='network-directives'
>
4177 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4178 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4181 <term><varname>Priority=
</varname></term>
4183 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
4184 priority field are tried for packets first.
</para>
4189 <term><varname>QuantumBytes=
</varname></term>
4191 <para>Specifies how many bytes to serve from leaf at once. When suffixed with K, M, or G, the
4192 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4198 <term><varname>MTUBytes=
</varname></term>
4200 <para>Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified
4201 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4206 <term><varname>OverheadBytes=
</varname></term>
4208 <para>Takes an unsigned integer which specifies per-packet size overhead used in rate
4209 computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4210 Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4215 <term><varname>Rate=
</varname></term>
4217 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
4218 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
4219 to the base of
1000. This setting is mandatory.
</para>
4224 <term><varname>CeilRate=
</varname></term>
4226 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
4227 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
4228 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
4234 <term><varname>BufferBytes=
</varname></term>
4236 <para>Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed
4237 with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
4238 to the base of
1024.
</para>
4243 <term><varname>CeilBufferBytes=
</varname></term>
4245 <para>Specifies the maximum bytes burst for ceil which can be accumulated during idle period.
4246 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4247 respectively, to the base of
1024.
</para>
4254 <title>[HeavyHitterFilter] Section Options
</title>
4255 <para>The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter
4258 <variablelist class='network-directives'
>
4259 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4260 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4263 <term><varname>PacketLimit=
</varname></term>
4265 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
4266 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
4267 kernel's default is used.
</para>
4274 <title>[QuickFairQueueing] Section Options
</title>
4275 <para>The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing
4278 <variablelist class='network-directives'
>
4279 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4280 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4285 <title>[QuickFairQueueingClass] Section Options
</title>
4286 <para>The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing
4289 <variablelist class='network-directives'
>
4290 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4291 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4294 <term><varname>Weight=
</varname></term>
4296 <para>Specifies the weight of the class. Takes an integer in the range
1…
1023. Defaults to
4297 unset in which case the kernel default is used.
</para>
4302 <term><varname>MaxPacketBytes=
</varname></term>
4304 <para>Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the
4305 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4306 1024. When unset, the kernel default is used.
</para>
4313 <title>[BridgeVLAN] Section Options
</title>
4314 <para>The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the
4315 following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The
4316 <varname>VLANFiltering=
</varname> option has to be enabled, see the [Bridge] section in
4317 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
4319 <variablelist class='network-directives'
>
4321 <term><varname>VLAN=
</varname></term>
4323 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. Takes
4324 an integer in the range
1…
4094.
</para>
4328 <term><varname>EgressUntagged=
</varname></term>
4330 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
4331 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
4332 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
4336 <term><varname>PVID=
</varname></term>
4338 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
4339 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
4340 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
4347 <title>Examples
</title>
4349 <title>Static network configuration
</title>
4351 <programlisting># /etc/systemd/network/
50-static.network
4356 Address=
192.168.0.15/
24
4357 Gateway=
192.168.0.1</programlisting>
4359 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
4360 specified gateway will be used for a default route.
</para>
4364 <title>DHCP on ethernet links
</title>
4366 <programlisting># /etc/systemd/network/
80-dhcp.network
4371 DHCP=yes
</programlisting>
4373 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
4374 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
4378 <title>IPv6 Prefix Delegation
</title>
4380 <programlisting># /etc/systemd/network/
55-ipv6-pd-upstream.network
4385 DHCP=ipv6
</programlisting>
4387 <programlisting># /etc/systemd/network/
56-ipv6-pd-downstream.network
4393 DHCPPrefixDelegation=yes
</programlisting>
4395 <para>This will enable DHCPv6-PD on the interface enp1s0 as an upstream interface where the
4396 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
4397 The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network.
4402 <title>A bridge with two enslaved links
</title>
4404 <programlisting># /etc/systemd/network/
25-bridge-static.network
4409 Address=
192.168.0.15/
24
4411 DNS=
192.168.0.1</programlisting>
4413 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
4418 Bridge=bridge0
</programlisting>
4420 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
4425 Bridge=bridge0
</programlisting>
4427 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
4428 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
4429 and network assigned, and a default route via the specified gateway will be
4430 added. The specified DNS server will be added to the global list of DNS resolvers.
4438 # /etc/systemd/network/
20-bridge-slave-interface-vlan.network
4454 EgressUntagged=
300-
400</programlisting>
4456 <para>This overrides the configuration specified in the previous example for the
4457 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
4458 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
4459 untagged when they leave on this interface. Untagged packets which arrive on this
4460 interface will be assigned VLAN ID
42.
</para>
4464 <title>Various tunnels
</title>
4466 <programlisting>/etc/systemd/network/
25-tunnels.network
4477 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
4483 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
4489 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
4495 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
4501 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
4502 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
4506 <title>A bond device
</title>
4508 <programlisting># /etc/systemd/network/
30-bond1.network
4516 <programlisting># /etc/systemd/network/
30-bond1.netdev
4522 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
4524 MACAddress=
52:
54:
00:e9:
64:
41
4530 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
4532 MACAddress=
52:
54:
00:e9:
64:
42
4538 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
4539 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
4540 will be used to acquire an address.
</para>
4544 <title>Virtual Routing and Forwarding (VRF)
</title>
4545 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
4546 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
4547 within the routing table defined during VRF creation. For kernels before
4.8 traffic
4548 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
4550 <programlisting># /etc/systemd/network/
25-vrf.network
4560 <title>MacVTap
</title>
4561 <para>This brings up a network interface
<literal>macvtap-test
</literal>
4562 and attaches it to
<literal>enp0s25
</literal>.
</para>
4563 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
4568 MACVTAP=macvtap-test
4573 <title>A Xfrm interface with physical underlying device.
</title>
4575 <programlisting># /etc/systemd/network/
27-xfrm.netdev
4580 InterfaceId=
7</programlisting>
4582 <programlisting># /etc/systemd/network/
27-eth0.network
4587 Xfrm=xfrm0
</programlisting>
4589 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
4590 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
4591 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
4597 <title>See Also
</title>
4599 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
4600 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
4601 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4602 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4603 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob