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>DHCPv6PrefixDelegation=
</varname> is enabled, then the delegated
858 prefixes are also distributed. See
<varname>DHCPv6PrefixDelegation=
</varname> setting and the
859 [IPv6SendRA], [IPv6Prefix], [IPv6RoutePrefix], and [DHCPv6PrefixDelegation] sections for more
860 configuration options.
</para></listitem>
863 <term><varname>DHCPv6PrefixDelegation=
</varname></term>
864 <listitem><para>Takes a boolean value. When enabled, requests prefixes using a DHCPv6 client
865 configured on another link. By default, an address within each delegated prefix will be
866 assigned, and the prefixes will be announced through IPv6 Router Advertisement when
867 <varname>IPv6SendRA=
</varname> is enabled. Such default settings can be configured in
868 [DHCPv6PrefixDelegation] section. Defaults to disabled.
</para></listitem>
871 <term><varname>IPv6MTUBytes=
</varname></term>
872 <listitem><para>Configures IPv6 maximum transmission unit (MTU).
873 An integer greater than or equal to
1280 bytes. When unset, the kernel's default will be used.
877 <term><varname>KeepMaster=
</varname></term>
879 <para>Takes a boolean value. When enabled, the current master interface index will not be
880 changed, and
<varname>BatmanAdvanced=
</varname>,
<varname>Bond=
</varname>,
881 <varname>Bridge=
</varname>, and
<varname>VRF=
</varname> settings are ignored. This may be
882 useful when a netdev with a master interface is created by another program, e.g.
883 <citerefentry><refentrytitle>systemd-nspawn
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
884 Defaults to false.
</para>
888 <term><varname>BatmanAdvanced=
</varname></term>
889 <term><varname>Bond=
</varname></term>
890 <term><varname>Bridge=
</varname></term>
891 <term><varname>VRF=
</varname></term>
893 <para>The name of the B.A.T.M.A.N. Advanced, bond, bridge, or VRF interface to add the link
895 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
900 <term><varname>IPoIB=
</varname></term>
901 <term><varname>IPVLAN=
</varname></term>
902 <term><varname>IPVTAP=
</varname></term>
903 <term><varname>L2TP=
</varname></term>
904 <term><varname>MACsec=
</varname></term>
905 <term><varname>MACVLAN=
</varname></term>
906 <term><varname>MACVTAP=
</varname></term>
907 <term><varname>Tunnel=
</varname></term>
908 <term><varname>VLAN=
</varname></term>
909 <term><varname>VXLAN=
</varname></term>
910 <term><varname>Xfrm=
</varname></term>
912 <para>The name of an IPoIB, IPVLAN, IPVTAP, L2TP, MACsec, MACVLAN, MACVTAP, tunnel, VLAN,
913 VXLAN, or Xfrm to be created on the link. See
914 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
915 This option may be specified more than once.
</para>
919 <term><varname>ActiveSlave=
</varname></term>
921 <para>Takes a boolean. Specifies the new active slave. The
<literal>ActiveSlave=
</literal>
922 option is only valid for following modes:
923 <literal>active-backup
</literal>,
924 <literal>balance-alb
</literal> and
925 <literal>balance-tlb
</literal>. Defaults to false.
930 <term><varname>PrimarySlave=
</varname></term>
932 <para>Takes a boolean. Specifies which slave is the primary device. The specified
933 device will always be the active slave while it is available. Only when the
934 primary is off-line will alternate devices be used. This is useful when
935 one slave is preferred over another, e.g. when one slave has higher throughput
936 than another. The
<literal>PrimarySlave=
</literal> option is only valid for
938 <literal>active-backup
</literal>,
939 <literal>balance-alb
</literal> and
940 <literal>balance-tlb
</literal>. Defaults to false.
945 <term><varname>ConfigureWithoutCarrier=
</varname></term>
947 <para>Takes a boolean. Allows networkd to configure a specific link even if it has no carrier.
948 Defaults to false. If enabled, and the
<varname>IgnoreCarrierLoss=
</varname> setting is not
949 explicitly set, then it is enabled as well.
954 <term><varname>IgnoreCarrierLoss=
</varname></term>
956 <para>Takes a boolean or a timespan. When true, networkd retains both the static and dynamic
957 configuration of the interface even if its carrier is lost. When a timespan is specified,
958 networkd waits for the specified timespan, and ignores the carrier loss if the link regain
959 its carrier within the timespan. Setting a finite timespan may be useful for a wireless
960 interface connecting to a network which has multiple access points with the same SSID, or an
961 interface which is reset on changing MTU. When unset, the value specified with
962 <varname>ConfigureWithoutCarrier=
</varname> is used.
</para>
964 <para>When
<varname>ActivationPolicy=
</varname> is set to
<literal>always-up
</literal>, this
965 is forced to
<literal>true
</literal>.
970 <term><varname>KeepConfiguration=
</varname></term>
972 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
973 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
974 will not drop static addresses and routes on starting up process. When set to
975 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
976 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
977 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
978 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
979 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
980 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
981 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
<literal>no
</literal>.
989 <title>[Address] Section Options
</title>
991 <para>An [Address] section accepts the following keys. Specify several [Address]
992 sections to configure several addresses.
</para>
994 <variablelist class='network-directives'
>
996 <term><varname>Address=
</varname></term>
998 <para>As in the [Network] section. This key is mandatory. Each [Address] section can contain one
999 <varname>Address=
</varname> setting.
</para>
1003 <term><varname>Peer=
</varname></term>
1005 <para>The peer address in a point-to-point connection.
1006 Accepts the same format as the
<varname>Address=
</varname>
1011 <term><varname>Broadcast=
</varname></term>
1013 <para>Takes an IPv4 address or boolean value. The address must be in the format described in
1014 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
1015 If set to true, then the IPv4 broadcast address will be derived from the
1016 <varname>Address=
</varname> setting. If set to false, then the broadcast address will not
1017 be set. Defaults to true, except for wireguard interfaces, where it default to false.
1022 <term><varname>Label=
</varname></term>
1024 <para>Specifies the label for the IPv4 address. The label must be a
7-bit ASCII string with
1025 a length of
1…
15 characters. Defaults to unset.
</para>
1029 <term><varname>PreferredLifetime=
</varname></term>
1031 <para>Allows the default
"preferred lifetime" of the address to be overridden. Only three
1032 settings are accepted:
<literal>forever
</literal>,
<literal>infinity
</literal>, which is the
1033 default and means that the address never expires, and
<literal>0</literal>, which means that the
1034 address is considered immediately
"expired" and will not be used, unless explicitly requested. A
1035 setting of
<option>PreferredLifetime=
0</option> is useful for addresses which are added to be
1036 used only by a specific application, which is then configured to use them explicitly.
</para>
1040 <term><varname>Scope=
</varname></term>
1042 <para>The scope of the address, which can be
1043 <literal>global
</literal> (valid everywhere on the network, even through a gateway),
1044 <literal>link
</literal> (only valid on this device, will not traverse a gateway) or
1045 <literal>host
</literal> (only valid within the device itself, e.g.
127.0.0.1)
1046 or an unsigned integer in the range
0…
255.
1047 Defaults to
<literal>global
</literal>.
</para>
1051 <term><varname>RouteMetric=
</varname></term>
1053 <para>The metric of the prefix route, which is pointing to the subnet of the configured IP
1054 address, taking the configured prefix length into account. Takes an unsigned integer in the
1055 range
0…
4294967295. When unset or set to
0, the kernel's default value is used. This
1056 setting will be ignored when
<varname>AddPrefixRoute=
</varname> is false.
</para>
1060 <term><varname>HomeAddress=
</varname></term>
1062 <para>Takes a boolean. Designates this address the
"home address" as defined in
1063 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>.
1064 Supported only on IPv6. Defaults to false.
</para>
1068 <term><varname>DuplicateAddressDetection=
</varname></term>
1070 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
1071 <literal>both
</literal>,
<literal>none
</literal>. When
<literal>ipv4
</literal>,
1072 performs IPv4 Address Conflict Detection. See
1073 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>.
1074 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
1075 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>.
1076 Defaults to
<literal>ipv6
</literal>.
</para>
1080 <term><varname>ManageTemporaryAddress=
</varname></term>
1082 <para>Takes a boolean. If true the kernel manage temporary addresses created
1083 from this one as template on behalf of Privacy Extensions
1084 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become
1085 active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
1086 The given address needs to have a prefix length of
64. This flag allows using privacy
1087 extensions in a manually configured network, just like if stateless auto-configuration
1088 was active. Defaults to false.
</para>
1092 <term><varname>AddPrefixRoute=
</varname></term>
1094 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
1095 Defaults to true.
</para>
1099 <term><varname>AutoJoin=
</varname></term>
1101 <para>Takes a boolean. Joining multicast group on ethernet level via
1102 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
1103 IGMP snooping since the switch would not replicate multicast packets on ports that did not
1104 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
1105 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
1106 that enables then to do the required join. By extending ip address command with option
1107 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
1108 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
1109 Defaults to
<literal>no
</literal>.
</para>
1116 <title>[Neighbor] Section Options
</title>
1117 <para>A [Neighbor] section accepts the following keys. The neighbor section adds a permanent, static
1118 entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the links
1119 matched for the network. Specify several [Neighbor] sections to configure several static neighbors.
1122 <variablelist class='network-directives'
>
1124 <term><varname>Address=
</varname></term>
1126 <para>The IP address of the neighbor.
</para>
1130 <term><varname>LinkLayerAddress=
</varname></term>
1132 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1139 <title>[IPv6AddressLabel] Section Options
</title>
1141 <para>An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel]
1142 sections to configure several address labels. IPv6 address labels are used for address selection. See
1143 <ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>. Precedence is managed by userspace,
1144 and only the label itself is stored in the kernel.
</para>
1146 <variablelist class='network-directives'
>
1148 <term><varname>Label=
</varname></term>
1150 <para>The label for the prefix, an unsigned integer in the range
0…
4294967294.
1151 0xffffffff is reserved. This setting is mandatory.
</para>
1155 <term><varname>Prefix=
</varname></term>
1157 <para>IPv6 prefix is an address with a prefix length, separated by a slash
<literal>/
</literal> character.
1158 This key is mandatory.
</para>
1165 <title>[RoutingPolicyRule] Section Options
</title>
1167 <para>An [RoutingPolicyRule] section accepts the following keys. Specify several [RoutingPolicyRule]
1168 sections to configure several rules.
</para>
1170 <variablelist class='network-directives'
>
1172 <term><varname>TypeOfService=
</varname></term>
1174 <para>Takes a number between
0 and
255 that specifies the type of service to match.
</para>
1178 <term><varname>From=
</varname></term>
1180 <para>Specifies the source address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1184 <term><varname>To=
</varname></term>
1186 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1190 <term><varname>FirewallMark=
</varname></term>
1192 <para>Specifies the iptables firewall mark value to match (a number between
1 and
1193 4294967295). Optionally, the firewall mask (also a number between
1 and
4294967295) can be
1194 suffixed with a slash (
<literal>/
</literal>), e.g.,
<literal>7/
255</literal>.
</para>
1198 <term><varname>Table=
</varname></term>
1200 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes one of predefined names
1201 <literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname>
1202 in
<citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1203 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1207 <term><varname>Priority=
</varname></term>
1209 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an unsigned
1210 integer in the range
0…
4294967295. Higher number means lower priority, and rules get
1211 processed in order of increasing number. Defaults to unset, and the kernel will pick
1212 a value dynamically.
</para>
1216 <term><varname>IncomingInterface=
</varname></term>
1218 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches packets originating from this host.
</para>
1222 <term><varname>OutgoingInterface=
</varname></term>
1224 <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>
1228 <term><varname>SourcePort=
</varname></term>
1230 <para>Specifies the source IP port or IP port range match in forwarding information base (FIB) rules.
1231 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1235 <term><varname>DestinationPort=
</varname></term>
1237 <para>Specifies the destination IP port or IP port range match in forwarding information base (FIB) rules.
1238 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1242 <term><varname>IPProtocol=
</varname></term>
1244 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP protocol name such as
<literal>tcp
</literal>,
1245 <literal>udp
</literal> or
<literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
<literal>tcp
</literal> or
1246 <literal>17</literal> for
<literal>udp
</literal>.
1247 Defaults to unset.
</para>
1251 <term><varname>InvertRule=
</varname></term>
1253 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1257 <term><varname>Family=
</varname></term>
1259 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1260 <literal>both
</literal>. By default, the address family is determined by the address
1261 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1262 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1263 <literal>ipv4
</literal>.
</para>
1267 <term><varname>User=
</varname></term>
1269 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1274 <term><varname>SuppressPrefixLength=
</varname></term>
1276 <para>Takes a number
<replaceable>N
</replaceable> in the range
0…
128 and rejects routing
1277 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1282 <term><varname>SuppressInterfaceGroup=
</varname></term>
1284 <para>Takes an integer in the range
0…
2147483647 and rejects routing decisions that have
1285 an interface with the same group id. It has the same meaning as
1286 <option>suppress_ifgroup
</option> in
<command>ip rule
</command>. Defaults to unset.
</para>
1290 <term><varname>Type=
</varname></term>
1292 <para>Specifies Routing Policy Database (RPDB) rule type. Takes one of
<literal>blackhole
</literal>,
1293 <literal>unreachable
</literal> or
<literal>prohibit
</literal>.
1301 <title>[NextHop] Section Options
</title>
1302 <para>The [NextHop] section is used to manipulate entries in the kernel's
"nexthop" tables. The
1303 [NextHop] section accepts the following keys. Specify several [NextHop] sections to configure several
1306 <variablelist class='network-directives'
>
1308 <term><varname>Id=
</varname></term>
1310 <para>The id of the next hop. Takes an unsigned integer in the range
1…
4294967295. If left
1311 unspecified, then automatically chosen by kernel.
</para>
1315 <term><varname>Gateway=
</varname></term>
1317 <para>As in the [Network] section.
</para>
1321 <term><varname>Family=
</varname></term>
1323 <para>Takes one of the special values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>.
1324 By default, the family is determined by the address specified in
1325 <varname>Gateway=
</varname>. If
<varname>Gateway=
</varname> is not specified, then defaults
1326 to
<literal>ipv4
</literal>.
</para>
1330 <term><varname>OnLink=
</varname></term>
1332 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1333 reachable directly by the current machine (i.e., attached to the local network), so that we
1334 can insert the nexthop in the kernel table without it being complained about. Defaults to
1335 <literal>no
</literal>.
</para>
1339 <term><varname>Blackhole=
</varname></term>
1341 <para>Takes a boolean. If enabled, packets to the corresponding routes are discarded
1342 silently, and
<varname>Gateway=
</varname> cannot be specified. Defaults to
1343 <literal>no
</literal>.
</para>
1347 <term><varname>Group=
</varname></term>
1349 <para>Takes a whitespace separated list of nexthop IDs. Each ID must be in the range
1350 1…
4294967295. Optionally, each nexthop ID can take a weight after a colon
1351 (
<literal><replaceable>id
</replaceable><optional>:
<replaceable>weight
</replaceable></optional></literal>).
1352 The weight must be in the range
1…
255. If the weight is not specified, then it is assumed
1353 that the weight is
1. This setting cannot be specified with
<varname>Gateway=
</varname>,
1354 <varname>Family=
</varname>,
<varname>Blackhole=
</varname>. This setting can be specified
1355 multiple times. If an empty string is assigned, then the all previous assignments are
1356 cleared. Defaults to unset.
</para>
1363 <title>[Route] Section Options
</title>
1364 <para>The [Route] section accepts the following keys. Specify several [Route] sections to configure
1365 several routes.
</para>
1367 <variablelist class='network-directives'
>
1369 <term><varname>Gateway=
</varname></term>
1371 <para>Takes the gateway address or the special values
<literal>_dhcp4
</literal> and
1372 <literal>_ipv6ra
</literal>. If
<literal>_dhcp4
</literal> or
<literal>_ipv6ra
</literal> is
1373 set, then the gateway address provided by DHCPv4 or IPv6 RA is used.
</para>
1377 <term><varname>GatewayOnLink=
</varname></term>
1379 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1380 reachable directly by the current machine (i.e., attached to the local network), so that we
1381 can insert the route in the kernel table without it being complained about. Defaults to
1382 <literal>no
</literal>.
</para>
1386 <term><varname>Destination=
</varname></term>
1388 <para>The destination prefix of the route. Possibly
1389 followed by a slash and the prefix length. If omitted, a
1390 full-length host route is assumed.
</para>
1394 <term><varname>Source=
</varname></term>
1396 <para>The source prefix of the route. Possibly followed by
1397 a slash and the prefix length. If omitted, a full-length
1398 host route is assumed.
</para>
1402 <term><varname>Metric=
</varname></term>
1404 <para>The metric of the route. Takes an unsigned integer in the range
0…
4294967295.
1405 Defaults to unset, and the kernel's default will be used.
</para>
1409 <term><varname>IPv6Preference=
</varname></term>
1411 <para>Specifies the route preference as defined in
<ulink
1412 url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink> for Router Discovery messages. Which
1413 can be one of
<literal>low
</literal> the route has a lowest priority,
<literal>medium
</literal>
1414 the route has a default priority or
<literal>high
</literal> the route has a highest priority.
1419 <term><varname>Scope=
</varname></term>
1421 <para>The scope of the IPv4 route, which can be
<literal>global
</literal>,
<literal>site
</literal>,
1422 <literal>link
</literal>,
<literal>host
</literal>, or
1423 <literal>nowhere
</literal>:
</para>
1425 <listitem><para><literal>global
</literal> means the route can reach
1426 hosts more than one hop away.
</para></listitem>
1428 <listitem><para><literal>site
</literal> means an interior route in
1429 the local autonomous system.
</para></listitem>
1431 <listitem><para><literal>link
</literal> means the route can only
1432 reach hosts on the local network (one hop away).
</para></listitem>
1434 <listitem><para><literal>host
</literal> means the route will not
1435 leave the local machine (used for internal addresses like
1436 127.0.0.1).
</para></listitem>
1438 <listitem><para><literal>nowhere
</literal> means the destination
1439 doesn't exist.
</para></listitem>
1441 <para>For IPv4 route, defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
1442 <literal>local
</literal> or
<literal>nat
</literal>,
1443 and
<literal>link
</literal> if
<varname>Type=
</varname> is
1444 <literal>broadcast
</literal>,
<literal>multicast
</literal>, or
<literal>anycast
</literal>.
1445 In other cases, defaults to
<literal>global
</literal>. The value is
1446 not used for IPv6.
</para>
1450 <term><varname>PreferredSource=
</varname></term>
1452 <para>The preferred source address of the route. The address
1453 must be in the format described in
1454 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
1458 <term><varname>Table=
</varname></term>
1460 <para>The table identifier for the route. Takes one of predefined names
<literal>default
</literal>,
<literal>main
</literal>,
1461 and
<literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname> in
<citerefentry><refentrytitle>networkd.conf
</refentrytitle>
1462 <manvolnum>5</manvolnum></citerefentry>, or a number between
1 and
4294967295. The table can be retrieved using
1463 <command>ip route show table
<replaceable>num
</replaceable></command>. If unset and
<varname>Type=
</varname> is
<literal>local
</literal>,
1464 <literal>broadcast
</literal>,
<literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1465 In other cases, defaults to
<literal>main
</literal>.
1470 <term><varname>Protocol=
</varname></term>
1472 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special values
1473 <literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1474 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1479 <term><varname>Type=
</varname></term>
1481 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1482 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1483 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1484 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1485 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e. a
1486 route indicating the path to take to a destination network address. If
<literal>blackhole
</literal>, packets
1487 to the defined route are discarded silently. If
<literal>unreachable
</literal>, packets to the defined route
1488 are discarded and the ICMP message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets
1489 to the defined route are discarded and the ICMP message
"Communication Administratively Prohibited" is
1490 generated. If
<literal>throw
</literal>, route lookup in the current routing table will fail and the route
1491 selection process will return to Routing Policy Database (RPDB). Defaults to
<literal>unicast
</literal>.
1496 <term><varname>InitialCongestionWindow=
</varname></term>
1498 <para>The TCP initial congestion window is used during the start of a TCP connection.
1499 During the start of a TCP session, when a client requests a resource, the server's initial
1500 congestion window determines how many packets will be sent during the initial burst of data
1501 without waiting for acknowledgement. Takes a number between
1 and
1023. Note that
100 is
1502 considered an extremely large value for this option. When unset, the kernel's default
1503 (typically
10) will be used.
</para>
1507 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1509 <para>The TCP initial advertised receive window is the amount of receive data (in bytes)
1510 that can initially be buffered at one time on a connection. The sending host can send only
1511 that amount of data before waiting for an acknowledgment and window update from the
1512 receiving host. Takes a number between
1 and
1023. Note that
100 is considered an extremely
1513 large value for this option. When unset, the kernel's default will be used.
</para>
1517 <term><varname>QuickAck=
</varname></term>
1519 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the kernel's default will be used.
1524 <term><varname>FastOpenNoCookie=
</varname></term>
1526 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1527 When unset, the kernel's default will be used.
1532 <term><varname>TTLPropagate=
</varname></term>
1534 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1535 When unset, the kernel's default will be used.
1540 <term><varname>MTUBytes=
</varname></term>
1542 <para>The maximum transmission unit in bytes to set for the
1543 route. The usual suffixes K, M, G, are supported and are
1544 understood to the base of
1024.
</para>
1545 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
1546 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
1550 <term><varname>IPServiceType=
</varname></term>
1552 <para>Takes string;
<literal>CS6
</literal> or
<literal>CS4
</literal>. Used to set IP
1553 service type to CS6 (network control) or CS4 (Realtime). Defaults to CS6.
</para>
1557 <term><varname>TCPAdvertisedMaximumSegmentSize=
</varname></term>
1559 <para>Specifies the Path MSS (in bytes) hints given on TCP layer. The usual suffixes K, M, G, are
1560 supported and are understood to the base of
1024. An unsigned integer in the range
1…
4294967294.
1561 When unset, the kernel's default will be used.
</para>
1565 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1567 <para>Configures multipath route. Multipath routing is the technique of using multiple
1568 alternative paths through a network. Takes gateway address. Optionally, takes a network
1569 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for
1570 this multipath route separated with whitespace. This setting can be specified multiple
1571 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
1575 <term><varname>NextHop=
</varname></term>
1577 <para>Specifies the nexthop id. Takes an unsigned integer in the range
1…
4294967295.
1578 If set, the corresponding [NextHop] section must be configured. Defaults to unset.
</para>
1585 <title>[DHCPv4] Section Options
</title>
1586 <para>The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the
1587 <varname>DHCP=
</varname> setting described above:
</para>
1589 <variablelist class='network-directives'
>
1591 <!-- DHCP packet contents -->
1594 <term><varname>SendHostname=
</varname></term>
1596 <para>When true (the default), the machine's hostname (or the value specified with
1597 <varname>Hostname=
</varname>, described below) will be sent to the DHCP server. Note that the
1598 hostname must consist only of
7-bit ASCII lower-case characters and no spaces or dots, and be
1599 formatted as a valid DNS domain name. Otherwise, the hostname is not sent even if this option is
1605 <term><varname>Hostname=
</varname></term>
1607 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's hostname.
1608 Note that the specified hostname must consist only of
7-bit ASCII lower-case characters and
1609 no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1614 <term><varname>MUDURL=
</varname></term>
1616 <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent to the
1617 DHCPv4 server. Takes a URL of length up to
255 characters. A superficial verification that the
1618 string is a valid URL will be performed. DHCPv4 clients are intended to have at most one MUD URL
1619 associated with them. See
<ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
1622 <para>MUD is an embedded software standard defined by the IETF that allows IoT device makers to
1623 advertise device specifications, including the intended communication patterns for their device
1624 when it connects to the network. The network can then use this to author a context-specific
1625 access policy, so the device functions only within those parameters.
</para>
1630 <term><varname>ClientIdentifier=
</varname></term>
1632 <para>The DHCPv4 client identifier to use. Takes one of
<option>mac
</option>,
1633 <option>duid
</option> or
<option>duid-only
</option>. If set to
<option>mac
</option>, the
1634 MAC address of the link is used. If set to
<option>duid
</option>, an RFC4361-compliant Client
1635 ID, which is the combination of IAID and DUID (see below), is used. If set to
1636 <option>duid-only
</option>, only DUID is used, this may not be RFC compliant, but some setups
1637 may require to use this. Defaults to
<option>duid
</option>.
</para>
1642 <term><varname>VendorClassIdentifier=
</varname></term>
1644 <para>The vendor class identifier used to identify vendor
1645 type and configuration.
</para>
1650 <term><varname>UserClass=
</varname></term>
1652 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or
1653 applications it represents. The information contained in this option is a string that represents
1654 the user class of which the client is a member. Each class sets an identifying string of
1655 information to be used by the DHCP service to classify clients. Takes a whitespace-separated list
1661 <term><varname>DUIDType=
</varname></term>
1663 <para>Override the global
<varname>DUIDType=
</varname> setting for this network. See
1664 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1665 for a description of possible values.
</para>
1670 <term><varname>DUIDRawData=
</varname></term>
1672 <para>Override the global
<varname>DUIDRawData=
</varname> setting for this network. See
1673 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1674 for a description of possible values.
</para>
1679 <term><varname>IAID=
</varname></term>
1681 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned
1687 <term><varname>Anonymize=
</varname></term>
1689 <para>Takes a boolean. When true, the options sent to the DHCP server will follow the
1690 <ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink> (Anonymity Profiles for
1691 DHCP Clients) to minimize disclosure of identifying information. Defaults to false.
</para>
1693 <para>This option should only be set to true when
<varname>MACAddressPolicy=
</varname> is
1694 set to
<option>random
</option> (see
1695 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
1698 <para>When true,
<varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1699 <varname>VendorClassIdentifier=
</varname>,
<varname>UserClass=
</varname>,
1700 <varname>RequestOptions=
</varname>,
<varname>SendOption=
</varname>,
1701 <varname>SendVendorOption=
</varname>, and
<varname>MUDURL=
</varname> are ignored.
</para>
1703 <para>With this option enabled DHCP requests will mimic those generated by Microsoft
1704 Windows, in order to reduce the ability to fingerprint and recognize installations. This
1705 means DHCP request sizes will grow and lease data will be more comprehensive than normally,
1706 though most of the requested data is not actually used.
</para>
1711 <term><varname>RequestOptions=
</varname></term>
1713 <para>Sets request options to be sent to the server in the DHCPv4 request options list. A
1714 whitespace-separated list of integers in the range
1…
254. Defaults to unset.
</para>
1719 <term><varname>SendOption=
</varname></term>
1721 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data type
1722 and data separated with a colon
1723 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1724 The option number must be an integer in the range
1…
254. The type takes one of
1725 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1726 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1727 string may be escaped using
<ulink
1728 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1729 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1730 then all options specified earlier are cleared. Defaults to unset.
</para>
1735 <term><varname>SendVendorOption=
</varname></term>
1737 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data
1738 type and data separated with a colon
1739 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1740 The option number must be an integer in the range
1…
254. The type takes one of
1741 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1742 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1743 string may be escaped using
<ulink
1744 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1745 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1746 then all options specified earlier are cleared. Defaults to unset.
</para>
1750 <!-- How to use the DHCP lease -->
1753 <term><varname>Label=
</varname></term>
1755 <para>Specifies the label for the IPv4 address received from the DHCP server.
1756 The label must be a
7-bit ASCII string with a length of
1…
15 characters.
1757 Defaults to unset.
</para>
1762 <term><varname>UseDNS=
</varname></term>
1764 <para>When true (the default), the DNS servers received from the DHCP server will be used.
</para>
1766 <para>This corresponds to the
<option>nameserver
</option>
1767 option in
<citerefentry
1768 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1773 <term><varname>RoutesToDNS=
</varname></term>
1775 <para>When true, the routes to the DNS servers received from the DHCP server will be
1776 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored.
1777 Defaults to true.
</para>
1782 <term><varname>UseNTP=
</varname></term>
1784 <para>When true (the default), the NTP servers received from the DHCP server will be used by
1785 <filename>systemd-timesyncd.service
</filename>.
</para>
1790 <term><varname>RoutesToNTP=
</varname></term>
1792 <para>When true, the routes to the NTP servers received from the DHCP server will be
1793 configured. When
<varname>UseNTP=
</varname> is disabled, this setting is ignored.
1794 Defaults to true.
</para>
1799 <term><varname>UseSIP=
</varname></term>
1801 <para>When true (the default), the SIP servers received from the DHCP server will be collected
1802 and made available to client programs.
</para>
1807 <term><varname>UseMTU=
</varname></term>
1809 <para>When true, the interface maximum transmission unit from the DHCP server will be used on the
1810 current link. If
<varname>MTUBytes=
</varname> is set, then this setting is ignored. Defaults to
1812 <para>Note, some drivers will reset the interfaces if the MTU is changed. For such
1813 interfaces, please try to use
<varname>IgnoreCarrierLoss=
</varname> with a short timespan,
1814 e.g.
<literal>3 seconds
</literal>.
</para>
1819 <term><varname>UseHostname=
</varname></term>
1821 <para>When true (the default), the hostname received from the DHCP server will be set as the
1822 transient hostname of the system.
</para>
1827 <term><varname>UseDomains=
</varname></term>
1829 <para>Takes a boolean, or the special value
<option>route
</option>. When true, the domain name
1830 received from the DHCP server will be used as DNS search domain over this link, similar to the
1831 effect of the
<option>Domains=
</option> setting. If set to
<option>route
</option>, the domain
1832 name received from the DHCP server will be used for routing DNS queries only, but not for
1833 searching, similar to the effect of the
<option>Domains=
</option> setting when the argument is
1834 prefixed with
<literal>~
</literal>. Defaults to false.
</para>
1836 <para>It is recommended to enable this option only on trusted networks, as setting this affects
1837 resolution of all hostnames, in particular of single-label names. It is generally safer to use
1838 the supplied domain only as routing domain, rather than as search domain, in order to not have it
1839 affect local resolution of single-label names.
</para>
1841 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
1842 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1848 <term><varname>UseRoutes=
</varname></term>
1850 <para>When true (the default), the static routes will be requested from the DHCP server and added
1851 to the routing table with a metric of
1024, and a scope of
<option>global
</option>,
1852 <option>link
</option> or
<option>host
</option>, depending on the route's destination and
1853 gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the link's own
1854 address, the scope will be set to
<option>host
</option>. Otherwise if the gateway is null (a
1855 direct route), a
<option>link
</option> scope will be used. For anything else, scope defaults to
1856 <option>global
</option>.
</para>
1861 <term><varname>RouteMetric=
</varname></term>
1863 <para>Set the routing metric for routes specified by the DHCP server (including the prefix
1864 route added for the specified prefix). Takes an unsigned integer in the range
0…
4294967295.
1865 Defaults to
1024.
</para>
1870 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1872 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to unset).
1873 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1875 <para>When used in combination with
<varname>VRF=
</varname>, the
1876 VRF's routing table is used when this parameter is not specified.
1882 <term><varname>RouteMTUBytes=
</varname></term>
1884 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further details.
</para>
1889 <term><varname>UseGateway=
</varname></term>
1891 <para>When true, the gateway will be requested from the DHCP server and added to the routing
1892 table with a metric of
1024, and a scope of
<option>link
</option>. When unset, the value specified
1893 with
<varname>UseRoutes=
</varname> is used.
</para>
1898 <term><varname>UseTimezone=
</varname></term>
1899 <listitem><para>When true, the timezone received from the DHCP server will be set as timezone of
1900 the local system. Defaults to false.
</para></listitem>
1904 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
1906 <para>Allows to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease lifetime.
1907 Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal>. The latter means that the
1908 address never expires. Defaults to unset.
</para>
1912 <!-- How to communicate with the server -->
1915 <term><varname>RequestBroadcast=
</varname></term>
1917 <para>Request the server to use broadcast messages before the IP address has been configured.
1918 This is necessary for devices that cannot receive RAW packets, or that cannot receive packets at
1919 all before an IP address has been configured. On the other hand, this must not be enabled on
1920 networks where broadcasts are filtered out.
</para>
1925 <term><varname>MaxAttempts=
</varname></term>
1927 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
1928 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>. Note that the
1929 time between retries is increased exponentially, up to approximately one per minute, so the
1930 network will not be overloaded even if this number is high. The default is suitable in most
1931 circumstances.
</para>
1936 <term><varname>ListenPort=
</varname></term>
1938 <para>Set the port from which the DHCP client packets originate.
</para>
1943 <term><varname>DenyList=
</varname></term>
1945 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
1946 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are
1947 rejected. Note that if
<varname>AllowList=
</varname> is configured then
1948 <varname>DenyList=
</varname> is ignored.
</para>
1953 <term><varname>AllowList=
</varname></term>
1955 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
1956 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are
1962 <term><varname>SendRelease=
</varname></term>
1964 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops. Defaults to
1970 <term><varname>SendDecline=
</varname></term>
1972 <para>A boolean. When
<literal>true
</literal>, the DHCPv4 client receives the IP address from the
1973 DHCP server. After a new IP is received, the DHCPv4 client performs IPv4 Duplicate Address
1974 Detection. If duplicate use is detected, the DHCPv4 client rejects the IP by sending a
1975 <constant>DHCPDECLINE
</constant> packet and tries to obtain an IP address again. See
<ulink
1976 url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>. Defaults to
1977 <literal>unset
</literal>.
</para>
1985 <title>[DHCPv6] Section Options
</title>
1986 <para>The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the
1987 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
</para>
1989 <variablelist class='network-directives'
>
1991 <!-- DHCP packet contents -->
1994 <term><varname>MUDURL=
</varname></term>
1995 <term><varname>IAID=
</varname></term>
1996 <term><varname>DUIDType=
</varname></term>
1997 <term><varname>DUIDRawData=
</varname></term>
1998 <term><varname>RequestOptions=
</varname></term>
2000 <para>As in the [DHCPv4] section.
</para>
2005 <term><varname>SendOption=
</varname></term>
2007 <para>As in the [DHCPv4] section, however because DHCPv6 uses
16-bit fields to store option
2008 numbers, the option number is an integer in the range
1…
65536.
</para>
2013 <term><varname>SendVendorOption=
</varname></term>
2015 <para>Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier, DHCP
2016 option number, data type, and data separated with a colon (
<literal><replaceable>enterprise
2017 identifier
</replaceable>:
<replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2018 Enterprise identifier is an unsigned integer in the range
1…
4294967294. The option number must be
2019 an integer in the range
1…
254. Data type takes one of
<literal>uint8
</literal>,
2020 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
2021 <literal>ipv6address
</literal>, or
<literal>string
</literal>. Special characters in the data
2022 string may be escaped using
<ulink
2023 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2024 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2025 then all options specified earlier are cleared. Defaults to unset.
</para>
2030 <term><varname>UserClass=
</varname></term>
2032 <para>A DHCPv6 client can use User Class option to identify the type or category of user or
2033 applications it represents. The information contained in this option is a string that represents
2034 the user class of which the client is a member. Each class sets an identifying string of
2035 information to be used by the DHCP service to classify clients. Special characters in the data
2036 string may be escaped using
<ulink
2037 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2038 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2039 then all options specified earlier are cleared. Takes a whitespace-separated list of
2040 strings. Note that currently
<constant>NUL
</constant> bytes are not allowed.
</para>
2045 <term><varname>VendorClass=
</varname></term>
2047 <para>A DHCPv6 client can use VendorClass option to identify the vendor that manufactured the
2048 hardware on which the client is running. The information contained in the data area of this
2049 option is contained in one or more opaque fields that identify details of the hardware
2050 configuration. Takes a whitespace-separated list of strings.
</para>
2055 <term><varname>PrefixDelegationHint=
</varname></term>
2057 <para>Takes an IPv6 address with prefix length in the same format as the
2058 <varname>Address=
</varname> in the [Network] section. The DHCPv6 client will include a prefix
2059 hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range
2060 1…
128. Defaults to unset.
</para>
2064 <!-- How to use the DHCP lease -->
2067 <term><varname>UseAddress=
</varname></term>
2069 <para>When true (the default), the IP addresses provided by the DHCPv6 server will be
2075 <term><varname>UseDelegatedPrefix=
</varname></term>
2077 <para>When true (the default), the client will request the DHCPv6 server to delegate
2078 prefixes. If the server provides prefixes to be delegated, then subnets of the prefixes are
2079 assigned to the interfaces which enables
<varname>DHCPv6PrefixDelegation=
</varname>.
2080 See also
<varname>DHCPv6PrefixDelegation=
</varname> in [Network] section,
2081 [DHCPv6PrefixDelegation] section, and
2082 <ulink url=
"https://www.rfc-editor.org/rfc/rfc8415.html#section-6.3">RFC
8415</ulink>.
2088 <term><varname>UseDNS=
</varname></term>
2089 <term><varname>UseNTP=
</varname></term>
2090 <term><varname>UseHostname=
</varname></term>
2091 <term><varname>UseDomains=
</varname></term>
2093 <para>As in the [DHCPv4] section.
</para>
2097 <!-- How to communicate with the server -->
2100 <term><varname>WithoutRA=
</varname></term>
2102 <para>Allows DHCPv6 client to start without router advertisements's managed or other
2103 address configuration flag. Takes one of
<literal>no
</literal>,
<literal>solicit
</literal>
2104 or
<literal>information-request
</literal>. If this is not specified,
2105 <literal>solicit
</literal> is used when
<varname>DHCPv6PrefixDelegation=
</varname> is
2106 enabled and
<varname>UplinkInterface=:self
</varname> is specified in the
2107 [DHCPv6PrefixDelegation] section. Otherwise, defaults to
<literal>no
</literal>, and the
2108 DHCPv6 client will be started when an RA is received. See also
2109 <varname>DHCPv6Client=
</varname> setting in the [IPv6AcceptRA] section.
</para>
2116 <title>[DHCPv6PrefixDelegation] Section Options
</title>
2117 <para>The [DHCPv6PrefixDelegation] section configures delegated prefixes assigned by DHCPv6 server.
2118 The settings in this section are used only when
<varname>DHCPv6PrefixDelegation=
</varname> setting
2121 <variablelist class='network-directives'
>
2123 <term><varname>UplinkInterface=
</varname></term>
2125 <para>Specifies the name or the index of the uplink interface, or one of the special values
2126 <literal>:self
</literal> and
<literal>:auto
</literal>. When
<literal>:self
</literal>, the
2127 interface itself is considered the uplink interface, and
2128 <varname>WithoutRA=solicit
</varname> is implied if the setting is not explicitly specified.
2129 When
<literal>:auto
</literal>, the first link which acquired prefixes to be delegated from
2130 the DHCPv6 server is selected. Defaults to
<literal>:auto
</literal>.
</para>
2135 <term><varname>SubnetId=
</varname></term>
2137 <para>Configure a specific subnet ID on the interface from a (previously) received prefix
2138 delegation. You can either set
"auto" (the default) or a specific subnet ID (as defined in
2139 <ulink url=
"https://tools.ietf.org/html/rfc4291#section-2.5.4">RFC
4291</ulink>, section
2140 2.5.4), in which case the allowed value is hexadecimal, from
0 to
0x7fffffffffffffff
2146 <term><varname>Announce=
</varname></term>
2148 <para>Takes a boolean. When enabled, and
<varname>IPv6SendRA=
</varname> in [Network] section
2149 is enabled, the delegated prefixes are distributed through the IPv6 Router Advertisement.
2150 Defaults to yes.
</para>
2155 <term><varname>Assign=
</varname></term>
2157 <para>Takes a boolean. Specifies whether to add an address from the delegated prefixes which
2158 are received from the WAN interface by the DHCPv6 Prefix Delegation. When true (on LAN
2159 interfce), the EUI-
64 algorithm will be used by default to form an interface identifier from
2160 the delegated prefixes. See also
<varname>Token=
</varname> setting below. Defaults to yes.
2166 <term><varname>Token=
</varname></term>
2168 <para>Specifies an optional address generation mode for assigning an address in each
2169 delegated prefix. This accepts the same syntax as
<varname>Token=
</varname> in the
2170 [IPv6AcceptRA] section. If
<varname>Assign=
</varname> is set to false, then this setting will
2171 be ignored. Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2176 <term><varname>ManageTemporaryAddress=
</varname></term>
2178 <para>As in the [Address] section, but defaults to true.
</para>
2183 <term><varname>RouteMetric=
</varname></term>
2185 <para>The metric of the route to the delegated prefix subnet. Takes an unsigned integer in
2186 the range
0…
4294967295. When set to
0, the kernel's default value is used. Defaults to
256.
2194 <title>[IPv6AcceptRA] Section Options
</title>
2195 <para>The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled
2196 with the
<varname>IPv6AcceptRA=
</varname> setting described above:
</para>
2198 <variablelist class='network-directives'
>
2200 <term><varname>Token=
</varname></term>
2202 <para>Specifies an optional address generation mode for the Stateless Address
2203 Autoconfiguration (SLAAC). The following values are supported:
</para>
2207 <term><option>eui64
</option></term>
2210 The EUI-
64 algorithm will be used to generate an address for that prefix. Only
2211 supported by Ethernet or InfiniBand interfaces.
2216 <term><option>static:
<replaceable>ADDRESS
</replaceable></option></term>
2219 An IPv6 address must be specified after a colon (
<literal>:
</literal>), and the
2220 lower bits of the supplied address are combined with the upper bits of a prefix
2221 received in a Router Advertisement (RA) message to form a complete address. Note
2222 that if multiple prefixes are received in an RA message, or in multiple RA messages,
2223 addresses will be formed from each of them using the supplied address. This mode
2224 implements SLAAC but uses a static interface identifier instead of an identifier
2225 generated by using the EUI-
64 algorithm. Because the interface identifier is static,
2226 if Duplicate Address Detection detects that the computed address is a duplicate
2227 (in use by another node on the link), then this mode will fail to provide an address
2228 for that prefix. If an IPv6 address without mode is specified, then
2229 <literal>static
</literal> mode is assumed.
2234 <term><option>prefixstable[:
<replaceable>ADDRESS
</replaceable>][,
<replaceable>UUID
</replaceable>]
</option></term>
2237 The algorithm specified in
2238 <ulink url=
"https://tools.ietf.org/html/rfc7217">RFC
7217</ulink> will be used to
2239 generate interface identifiers. This mode can optionally take an IPv6 address
2240 separated with a colon (
<literal>:
</literal>). If an IPv6 address is specified,
2241 then an interface identifier is generated only when a prefix received in an RA
2242 message matches the supplied address.
2245 This mode can also optionally take a non-null UUID in the format which
2246 <function>sd_id128_from_string()
</function> accepts, e.g.
2247 <literal>86b123b969ba4b7eb8b3d8605123525a
</literal> or
2248 <literal>86b123b9-
69ba-
4b7e-b8b3-d8605123525a
</literal>. If a UUID is specified, the
2249 value is used as the secret key to generate interface identifiers. If not specified,
2250 then an application specific ID generated with the system's machine-ID will be used
2251 as the secret key. See
2252 <citerefentry><refentrytitle>sd-id128
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2253 <citerefentry><refentrytitle>sd_id128_from_string
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2255 <citerefentry><refentrytitle>sd_id128_get_machine
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2258 Note that the
<literal>prefixstable
</literal> algorithm uses both the interface
2259 name and MAC address as input to the hash to compute the interface identifier, so
2260 if either of those are changed the resulting interface identifier (and address)
2261 will be changed, even if the prefix received in the RA message has not been
2268 <para>If no address generation mode is specified (which is the default), or a received
2269 prefix does not match any of the addresses provided in
<literal>prefixstable
</literal>
2270 mode, then the EUI-
64 algorithm will be used for Ethernet or InfiniBand interfaces,
2271 otherwise
<literal>prefixstable
</literal> will be used to form an interface identifier for
2274 <para>This setting can be specified multiple times. If an empty string is assigned, then
2275 the all previous assignments are cleared.
</para>
2278 <programlisting>Token=eui64
2280 Token=static:::
1a:
2b:
3c:
4d
2282 Token=prefixstable:
2002:da8:
1::
</programlisting></para>
2287 <term><varname>UseDNS=
</varname></term>
2289 <para>When true (the default), the DNS servers received in the Router Advertisement will be used.
</para>
2291 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
2292 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2297 <term><varname>UseDomains=
</varname></term>
2299 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
2300 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
2301 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
2302 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
2303 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
2304 <literal>~
</literal>. Defaults to false.
</para>
2306 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
2307 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
2308 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
2309 single-label names.
</para>
2311 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
2312 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2317 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
2319 <para>The table identifier for the routes received in the Router Advertisement
2320 (a number between
1 and
4294967295, or
0 to unset).
2321 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
2327 <term><varname>RouteMetric=
</varname></term>
2329 <para>Set the routing metric for the routes received in the Router Advertisement. Takes an
2330 unsigned integer in the range
0…
4294967295. Defaults to
1024.
</para>
2335 <term><varname>UseMTU=
</varname></term>
2337 <para>Takes a boolean. When true, the MTU received in the Router Advertisement will be
2338 used. Defaults to true.
</para>
2343 <term><varname>UseGateway=
</varname></term>
2345 <para>When true (the default), the router address will be configured as the default gateway.
2351 <term><varname>UseRoutePrefix=
</varname></term>
2353 <para>When true (the default), the routes corresponding to the route prefixes received in
2354 the Router Advertisement will be configured.
</para>
2359 <term><varname>UseAutonomousPrefix=
</varname></term>
2361 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
2362 precedence over any statically configured ones.
</para>
2367 <term><varname>UseOnLinkPrefix=
</varname></term>
2369 <para>When true (the default), the onlink prefix received in the Router Advertisement will be
2370 used and takes precedence over any statically configured ones.
</para>
2375 <term><varname>RouterDenyList=
</varname></term>
2377 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2378 take a prefix length after
<literal>/
</literal>. Any information advertised by the listed
2379 router is ignored.
</para>
2384 <term><varname>RouterAllowList=
</varname></term>
2386 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2387 take a prefix length after
<literal>/
</literal>. Only information advertised by the listed
2388 router is accepted. Note that if
<varname>RouterAllowList=
</varname> is configured then
2389 <varname>RouterDenyList=
</varname> is ignored.
</para>
2394 <term><varname>PrefixDenyList=
</varname></term>
2396 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2397 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2398 in the list are ignored.
</para>
2403 <term><varname>PrefixAllowList=
</varname></term>
2405 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2406 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2407 in the list are allowed. Note that if
<varname>PrefixAllowList=
</varname> is configured
2408 then
<varname>PrefixDenyList=
</varname> is ignored.
</para>
2413 <term><varname>RouteDenyList=
</varname></term>
2415 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2416 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2417 advertisements in the list are ignored.
</para>
2422 <term><varname>RouteAllowList=
</varname></term>
2424 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2425 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2426 advertisements in the list are allowed. Note that if
<varname>RouteAllowList=
</varname> is
2427 configured then
<varname>RouteDenyList=
</varname> is ignored.
</para>
2432 <term><varname>DHCPv6Client=
</varname></term>
2434 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true, the
2435 DHCPv6 client will be started when the RA has the managed or other information flag. If set
2436 to
<literal>always
</literal>, the DHCPv6 client will be started in managed mode when an RA
2437 is received, even if neither managed nor other information flag is set in the RA. This will
2438 be ignored when
<varname>WithoutRA=
</varname> in the [DHCPv6] section is enabled, or
2439 <varname>UplinkInterface=:self
</varname> in the [DHCPv6PrefixDelegation] section is
2440 specified. Defaults to true.
</para>
2447 <title>[DHCPServer] Section Options
</title>
2448 <para>The [DHCPServer] section contains settings for the DHCP server, if enabled via the
2449 <varname>DHCPServer=
</varname> option described above:
</para>
2451 <variablelist class='network-directives'
>
2454 <term><varname>ServerAddress=
</varname></term>
2455 <listitem><para>Specifies server address for the DHCP server. Takes an IPv4 address with prefix
2456 length, for example
<literal>192.168.0.1/
24</literal>. This setting may be useful when the link on
2457 which the DHCP server is running has multiple static addresses. When unset, one of static addresses
2458 in the link will be automatically selected. Defaults to unset.
</para></listitem>
2462 <term><varname>PoolOffset=
</varname></term>
2463 <term><varname>PoolSize=
</varname></term>
2465 <listitem><para>Configures the pool of addresses to hand out. The pool
2466 is a contiguous sequence of IP addresses in the subnet configured for
2467 the server address, which does not include the subnet nor the broadcast
2468 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
2469 from the start of subnet, or zero to use the default value.
2470 <varname>PoolSize=
</varname> takes the number of IP addresses in the
2471 pool or zero to use the default value. By default, the pool starts at
2472 the first address after the subnet address and takes up the rest of
2473 the subnet, excluding the broadcast address. If the pool includes
2474 the server address (the default), this is reserved and not handed
2475 out to clients.
</para></listitem>
2479 <term><varname>DefaultLeaseTimeSec=
</varname></term>
2480 <term><varname>MaxLeaseTimeSec=
</varname></term>
2482 <listitem><para>Control the default and maximum DHCP lease
2483 time to pass to clients. These settings take time values in seconds or
2484 another common time unit, depending on the suffix. The default
2485 lease time is used for clients that did not ask for a specific
2486 lease time. If a client asks for a lease time longer than the
2487 maximum lease time, it is automatically shortened to the
2488 specified time. The default lease time defaults to
1h, the
2489 maximum lease time to
12h. Shorter lease times are beneficial
2490 if the configuration data in DHCP leases changes frequently
2491 and clients shall learn the new settings with shorter
2492 latencies. Longer lease times reduce the generated DHCP
2493 network traffic.
</para></listitem>
2497 <term><varname>UplinkInterface=
</varname></term>
2498 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2499 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS, NTP, or SIP
2500 servers is enabled but no servers are specified, the servers configured in the uplink interface
2501 will be emitted. When
<literal>:auto
</literal>, the link which has a default gateway with the
2502 highest priority will be automatically selected. When
<literal>:none
</literal>, no uplink
2503 interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2507 <term><varname>EmitDNS=
</varname></term>
2508 <term><varname>DNS=
</varname></term>
2510 <listitem><para><varname>EmitDNS=
</varname> takes a boolean. Configures whether the DHCP leases
2511 handed out to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>. The
2512 DNS servers to pass to clients may be configured with the
<varname>DNS=
</varname> option, which takes
2513 a list of IPv4 addresses. If the
<varname>EmitDNS=
</varname> option is enabled but no servers
2514 configured, the servers are automatically propagated from an
"uplink" interface that has appropriate
2515 servers set. The
"uplink" interface is determined by the default route of the system with the highest
2516 priority. Note that this information is acquired at the time the lease is handed out, and does not
2517 take uplink interfaces into account that acquire DNS server information at a later point. If no
2518 suitable uplink interface is found the DNS server data from
<filename>/etc/resolv.conf
</filename> is
2519 used. Also, note that the leases are not refreshed if the uplink network configuration changes. To
2520 ensure clients regularly acquire the most current uplink DNS server information, it is thus advisable
2521 to shorten the DHCP lease time via
<varname>MaxLeaseTimeSec=
</varname> described
2522 above.
</para></listitem>
2526 <term><varname>EmitNTP=
</varname></term>
2527 <term><varname>NTP=
</varname></term>
2528 <term><varname>EmitSIP=
</varname></term>
2529 <term><varname>SIP=
</varname></term>
2530 <term><varname>EmitPOP3=
</varname></term>
2531 <term><varname>POP3=
</varname></term>
2532 <term><varname>EmitSMTP=
</varname></term>
2533 <term><varname>SMTP=
</varname></term>
2534 <term><varname>EmitLPR=
</varname></term>
2535 <term><varname>LPR=
</varname></term>
2537 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname> settings
2538 described above, these settings configure whether and what server information for the indicate
2539 protocol shall be emitted as part of the DHCP lease. The same syntax, propagation semantics and
2540 defaults apply as for
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname>.
</para></listitem>
2544 <term><varname>EmitRouter=
</varname></term>
2545 <term><varname>Router=
</varname></term>
2547 <listitem><para>The
<varname>EmitRouter=
</varname> setting takes a boolean value, and configures
2548 whether the DHCP lease should contain the router option. The
<varname>Router=
</varname> setting
2549 takes an IPv4 address, and configures the router address to be emitted. When the
2550 <varname>Router=
</varname> setting is not specified, then the server address will be used for
2551 the router option. When the
<varname>EmitRouter=
</varname> setting is disabled, the
2552 <varname>Router=
</varname> setting will be ignored. The
<varname>EmitRouter=
</varname> setting
2553 defaults to true, and the
<varname>Router=
</varname> setting defaults to unset.
2558 <term><varname>EmitTimezone=
</varname></term>
2559 <term><varname>Timezone=
</varname></term>
2561 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2562 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2563 <varname>Timezone=
</varname> setting takes a timezone string
2564 (such as
<literal>Europe/Berlin
</literal> or
2565 <literal>UTC
</literal>) to pass to clients. If no explicit
2566 timezone is set, the system timezone of the local host is
2567 propagated, as determined by the
2568 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2572 <term><varname>SendOption=
</varname></term>
2574 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2575 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2576 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2577 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2578 <literal>string
</literal>. Special characters in the data string may be escaped using
2579 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2580 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2581 then all options specified earlier are cleared. Defaults to unset.
</para>
2586 <term><varname>SendVendorOption=
</varname></term>
2588 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2589 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2590 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2591 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2592 <literal>string
</literal>. Special characters in the data string may be escaped using
2593 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2594 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2595 then all options specified earlier are cleared. Defaults to unset.
</para>
2599 <term><varname>BindToInterface=
</varname></term>
2601 <para>Takes a boolean value. When
<literal>yes
</literal>, DHCP server socket will be bound
2602 to its network interface and all socket communication will be restricted to this interface.
2603 Defaults to
<literal>yes
</literal>, except if
<varname>RelayTarget=
</varname> is used (see below),
2604 in which case it defaults to
<literal>no
</literal>.
</para>
2608 <term><varname>RelayTarget=
</varname></term>
2610 <para>Takes an IPv4 address, which must be in the format described in
2611 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
2612 Turns this DHCP server into a DHCP relay agent. See
<ulink url=
"https://tools.ietf.org/html/rfc1542">RFC
1542</ulink>.
2613 The address is the address of DHCP server or another relay agent to forward DHCP messages to and from.
</para>
2617 <term><varname>RelayAgentCircuitId=
</varname></term>
2619 <para>Specifies value for Agent Circuit ID suboption of Relay Agent Information option.
2620 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2621 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2622 Defaults to unset (means no Agent Circuit ID suboption is generated).
2623 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2627 <term><varname>RelayAgentRemoteId=
</varname></term>
2629 <para>Specifies value for Agent Remote ID suboption of Relay Agent Information option.
2630 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2631 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2632 Defaults to unset (means no Agent Remote ID suboption is generated).
2633 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2641 <title>[DHCPServerStaticLease] Section Options
</title>
2642 <para>The
<literal>[DHCPServerStaticLease]
</literal> section configures a static DHCP lease to assign a
2643 fixed IPv4 address to a specific device based on its MAC address. This section can be specified multiple
2646 <variablelist class='network-directives'
>
2648 <term><varname>MACAddress=
</varname></term>
2650 <listitem><para>The hardware address of a device to match. This key is mandatory.
</para></listitem>
2654 <term><varname>Address=
</varname></term>
2656 <listitem><para>The IPv4 address that should be assigned to the device that was matched with
2657 <varname>MACAddress=
</varname>. This key is mandatory.
</para></listitem>
2663 <title>[IPv6SendRA] Section Options
</title>
2664 <para>The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether
2665 to act as a router, if enabled via the
<varname>IPv6SendRA=
</varname> option described above. IPv6
2666 network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections.
2669 <variablelist class='network-directives'
>
2672 <term><varname>Managed=
</varname></term>
2673 <term><varname>OtherInformation=
</varname></term>
2675 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2676 addresses on the network link when
<varname>Managed=
</varname>
2677 is set to
<literal>true
</literal> or if only additional network
2678 information can be obtained via DHCPv6 for the network link when
2679 <varname>OtherInformation=
</varname> is set to
2680 <literal>true
</literal>. Both settings default to
2681 <literal>false
</literal>, which means that a DHCPv6 server is not being
2682 used.
</para></listitem>
2686 <term><varname>RouterLifetimeSec=
</varname></term>
2688 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. The value must be
0
2689 seconds, or between
4 seconds and
9000 seconds. When set to
0, the host is not acting as a router.
2690 Defaults to
1800 seconds (
30 minutes).
</para>
2695 <term><varname>RouterPreference=
</varname></term>
2697 <listitem><para>Configures IPv6 router preference if
2698 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2699 <literal>high
</literal>,
<literal>medium
</literal> and
2700 <literal>low
</literal>, with
<literal>normal
</literal> and
2701 <literal>default
</literal> added as synonyms for
2702 <literal>medium
</literal> just to make configuration easier. See
2703 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2704 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2708 <term><varname>UplinkInterface=
</varname></term>
2709 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2710 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS servers or
2711 search domains is enabled but no servers are specified, the servers configured in the uplink
2712 interface will be emitted. When
<literal>:auto
</literal>, the value specified to the same
2713 setting in the [DHCPv6PrefixDelegation] section will be used if
2714 <varname>DHCPv6PrefixDelegation=
</varname> is enabled, otherwise the link which has a default
2715 gateway with the highest priority will be automatically selected. When
<literal>:none
</literal>,
2716 no uplink interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2720 <term><varname>EmitDNS=
</varname></term>
2721 <term><varname>DNS=
</varname></term>
2723 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses
2724 that are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is true.
2725 <varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that case
2726 the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS servers are
2727 read from the [Network] section. If the [Network] section does not contain any DNS servers
2728 either, DNS servers from the uplink interface specified in
<varname>UplinkInterface=
</varname>
2729 will be used. When
<varname>EmitDNS=
</varname> is false, no DNS server information is sent in
2730 Router Advertisement messages.
<varname>EmitDNS=
</varname> defaults to true.
</para></listitem>
2734 <term><varname>EmitDomains=
</varname></term>
2735 <term><varname>Domains=
</varname></term>
2737 <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when
2738 <varname>EmitDomains=
</varname> is true. If
<varname>Domains=
</varname> is empty, DNS search
2739 domains are read from the [Network] section. If the [Network] section does not contain any DNS
2740 search domains either, DNS search domains from the uplink interface specified in
2741 <varname>UplinkInterface=
</varname> will be used. When
<varname>EmitDomains=
</varname> is false,
2742 no DNS search domain information is sent in Router Advertisement messages.
2743 <varname>EmitDomains=
</varname> defaults to true.
</para></listitem>
2747 <term><varname>DNSLifetimeSec=
</varname></term>
2749 <listitem><para>Lifetime in seconds for the DNS server addresses listed in
2750 <varname>DNS=
</varname> and search domains listed in
<varname>Domains=
</varname>. Defaults to
2751 3600 seconds (one hour).
</para></listitem>
2758 <title>[IPv6Prefix] Section Options
</title>
2759 <para>One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router
2760 Advertisements. See
<ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink> for further
2763 <variablelist class='network-directives'
>
2766 <term><varname>AddressAutoconfiguration=
</varname></term>
2767 <term><varname>OnLink=
</varname></term>
2769 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2770 autoconfigured with this prefix and whether the prefix can be used for
2771 onlink determination. Both settings default to
<literal>true
</literal>
2772 in order to ease configuration.
2777 <term><varname>Prefix=
</varname></term>
2779 <listitem><para>The IPv6 prefix that is to be distributed to hosts. Similarly to configuring static
2780 IPv6 addresses, the setting is configured as an IPv6 prefix and its prefix length, separated by a
2781 <literal>/
</literal> character. Use multiple [IPv6Prefix] sections to configure multiple IPv6
2782 prefixes since prefix lifetimes, address autoconfiguration and onlink status may differ from one
2783 prefix to another.
</para></listitem>
2787 <term><varname>PreferredLifetimeSec=
</varname></term>
2788 <term><varname>ValidLifetimeSec=
</varname></term>
2790 <listitem><para>Preferred and valid lifetimes for the prefix measured in seconds.
2791 <varname>PreferredLifetimeSec=
</varname> defaults to
1800 seconds (
30 minutes) and
2792 <varname>ValidLifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2796 <term><varname>Assign=
</varname></term>
2797 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2802 <term><varname>Token=
</varname></term>
2804 <para>Specifies an optional address generation mode for assigning an address in each
2805 prefix. This accepts the same syntax as
<varname>Token=
</varname> in the [IPv6AcceptRA]
2806 section. If
<varname>Assign=
</varname> is set to false, then this setting will be ignored.
2807 Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2812 <term><varname>RouteMetric=
</varname></term>
2814 <para>The metric of the prefix route. Takes an unsigned integer in the range
0…
4294967295.
2815 When unset or set to
0, the kernel's default value is used. This setting is ignored when
2816 <varname>Assign=
</varname> is false.
</para>
2823 <title>[IPv6RoutePrefix] Section Options
</title>
2824 <para>One or more [IPv6RoutePrefix] sections contain the IPv6
2825 prefix routes that are announced via Router Advertisements. See
2826 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2827 for further details.
</para>
2829 <variablelist class='network-directives'
>
2832 <term><varname>Route=
</varname></term>
2834 <listitem><para>The IPv6 route that is to be distributed to hosts. Similarly to configuring static
2835 IPv6 routes, the setting is configured as an IPv6 prefix routes and its prefix route length,
2836 separated by a
<literal>/
</literal> character. Use multiple [IPv6PrefixRoutes] sections to configure
2837 multiple IPv6 prefix routes.
</para></listitem>
2841 <term><varname>LifetimeSec=
</varname></term>
2843 <listitem><para>Lifetime for the route prefix measured in seconds.
2844 <varname>LifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2851 <title>[Bridge] Section Options
</title>
2852 <para>The [Bridge] section accepts the following keys:
</para>
2853 <variablelist class='network-directives'
>
2855 <term><varname>UnicastFlood=
</varname></term>
2857 <para>Takes a boolean. Controls whether the bridge should flood
2858 traffic for which an FDB entry is missing and the destination
2859 is unknown through this port. When unset, the kernel's default will be used.
2864 <term><varname>MulticastFlood=
</varname></term>
2866 <para>Takes a boolean. Controls whether the bridge should flood
2867 traffic for which an MDB entry is missing and the destination
2868 is unknown through this port. When unset, the kernel's default will be used.
2873 <term><varname>MulticastToUnicast=
</varname></term>
2875 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
2876 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
2877 When unset, the kernel's default will be used.
2882 <term><varname>NeighborSuppression=
</varname></term>
2884 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
2885 this port. When unset, the kernel's default will be used.
2890 <term><varname>Learning=
</varname></term>
2892 <para>Takes a boolean. Configures whether MAC address learning is enabled for
2893 this port. When unset, the kernel's default will be used.
2898 <term><varname>HairPin=
</varname></term>
2900 <para>Takes a boolean. Configures whether traffic may be sent back out of the port on which it
2901 was received. When this flag is false, then the bridge will not forward traffic back out of the
2902 receiving port. When unset, the kernel's default will be used.
</para>
2906 <term><varname>UseBPDU=
</varname></term>
2908 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
2909 processed by the bridge port. When unset, the kernel's default will be used.
</para>
2913 <term><varname>FastLeave=
</varname></term>
2915 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
2916 traffic on a port that receives an IGMP Leave message. It is only used with
2917 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
2921 <term><varname>AllowPortToBeRoot=
</varname></term>
2923 <para>Takes a boolean. Configures whether a given port is allowed to
2924 become a root port. Only used when STP is enabled on the bridge.
2925 When unset, the kernel's default will be used.
</para>
2929 <term><varname>ProxyARP=
</varname></term>
2931 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
2932 When unset, the kernel's default will be used.
</para>
2936 <term><varname>ProxyARPWiFi=
</varname></term>
2938 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
2939 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
2940 When unset, the kernel's default will be used.
</para>
2944 <term><varname>MulticastRouter=
</varname></term>
2946 <para>Configures this port for having multicast routers attached. A port with a multicast
2947 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
2948 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
2949 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
2950 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
2951 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
2955 <term><varname>Cost=
</varname></term>
2957 <para>Sets the
"cost" of sending packets of this interface.
2958 Each port in a bridge may have a different speed and the cost
2959 is used to decide which link to use. Faster interfaces
2960 should have lower costs. It is an integer value between
1 and
2965 <term><varname>Priority=
</varname></term>
2967 <para>Sets the
"priority" of sending packets on this interface.
2968 Each port in a bridge may have a different priority which is used
2969 to decide which link to use. Lower value means higher priority.
2970 It is an integer value between
0 to
63. Networkd does not set any
2971 default, meaning the kernel default value of
32 is used.
</para>
2977 <title>[BridgeFDB] Section Options
</title>
2978 <para>The [BridgeFDB] section manages the forwarding database table of a port and accepts the following
2979 keys. Specify several [BridgeFDB] sections to configure several static MAC table entries.
</para>
2981 <variablelist class='network-directives'
>
2983 <term><varname>MACAddress=
</varname></term>
2985 <para>As in the [Network] section. This key is mandatory.
</para>
2989 <term><varname>Destination=
</varname></term>
2991 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
2995 <term><varname>VLANId=
</varname></term>
2997 <para>The VLAN ID for the new static MAC table entry. If
2998 omitted, no VLAN ID information is appended to the new static MAC
3003 <term><varname>VNI=
</varname></term>
3005 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
3006 the remote VXLAN tunnel endpoint. Takes a number in the range
1…
16777215.
3007 Defaults to unset.
</para>
3011 <term><varname>AssociatedWith=
</varname></term>
3013 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
3014 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
3015 <literal>use
</literal> means the address is in use. User space can use this option to
3016 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
3017 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
3018 means the address is associated with master devices fdb.
<literal>router
</literal> means
3019 the destination address is associated with a router. Note that it's valid if the referenced
3020 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
3024 <term><varname>OutgoingInterface=
</varname></term>
3026 <para>Specifies the name or index of the outgoing interface for the VXLAN device driver to
3027 reach the remote VXLAN tunnel endpoint. Defaults to unset.
</para>
3033 <title>[BridgeMDB] Section Options
</title>
3034 <para>The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following
3035 keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.
</para>
3037 <variablelist class='network-directives'
>
3039 <term><varname>MulticastGroupAddress=
</varname></term>
3041 <para>Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.
</para>
3045 <term><varname>VLANId=
</varname></term>
3047 <para>The VLAN ID for the new entry. Valid ranges are
0 (no VLAN) to
4094. Optional, defaults to
0.
</para>
3054 <title>[LLDP] Section Options
</title>
3055 <para>The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following
3057 <variablelist class='network-directives'
>
3059 <term><varname>MUDURL=
</varname></term>
3061 <para>When configured, the specified Manufacturer Usage Descriptions (MUD) URL will be sent in
3062 LLDP packets. The syntax and semantics are the same as for
<varname>MUDURL=
</varname> in the
3063 [DHCPv4] section described above.
</para>
3065 <para>The MUD URLs received via LLDP packets are saved and can be read using the
3066 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
3073 <title>[CAN] Section Options
</title>
3074 <para>The [CAN] section manages the Controller Area Network (CAN bus) and accepts the
3075 following keys:
</para>
3076 <variablelist class='network-directives'
>
3078 <term><varname>BitRate=
</varname></term>
3080 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
3081 be used here. Takes a number in the range
1…
4294967295.
</para>
3085 <term><varname>SamplePoint=
</varname></term>
3087 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
3088 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>). This will be ignored when
3089 <varname>BitRate=
</varname> is unspecified.
</para>
3093 <term><varname>TimeQuantaNSec=
</varname></term>
3094 <term><varname>PropagationSegment=
</varname></term>
3095 <term><varname>PhaseBufferSegment1=
</varname></term>
3096 <term><varname>PhaseBufferSegment2=
</varname></term>
3097 <term><varname>SyncJumpWidth=
</varname></term>
3099 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3100 synchronization jump width, which allow to define the CAN bit-timing in a hardware
3101 independent format as proposed by the Bosch CAN
2.0 Specification.
3102 <varname>TimeQuantaNSec=
</varname> takes a timespan in nanoseconds.
3103 <varname>PropagationSegment=
</varname>,
<varname>PhaseBufferSegment1=
</varname>,
3104 <varname>PhaseBufferSegment2=
</varname>, and
<varname>SyncJumpWidth=
</varname> take number
3105 of time quantum specified in
<varname>TimeQuantaNSec=
</varname> and must be an unsigned
3106 integer in the range
0…
4294967295. These settings except for
3107 <varname>SyncJumpWidth=
</varname> will be ignored when
<varname>BitRate=
</varname> is
3112 <term><varname>DataBitRate=
</varname></term>
3113 <term><varname>DataSamplePoint=
</varname></term>
3115 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
3116 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
3120 <term><varname>DataTimeQuantaNSec=
</varname></term>
3121 <term><varname>DataPropagationSegment=
</varname></term>
3122 <term><varname>DataPhaseBufferSegment1=
</varname></term>
3123 <term><varname>DataPhaseBufferSegment2=
</varname></term>
3124 <term><varname>DataSyncJumpWidth=
</varname></term>
3126 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3127 synchronization jump width for the data phase, if CAN-FD is used. These settings are
3128 analogous to the
<varname>TimeQuantaNSec=
</varname> or related settings.
</para>
3132 <term><varname>FDMode=
</varname></term>
3134 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
3135 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
3136 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys, or
3137 <varname>DataTimeQuanta=
</varname> and related settings.
</para>
3141 <term><varname>FDNonISO=
</varname></term>
3143 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
3144 interface. When unset, the kernel's default will be used.
</para>
3148 <term><varname>RestartSec=
</varname></term>
3150 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
3151 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
3152 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
3153 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
3154 automatic restart off. By default automatic restart is disabled.
</para>
3158 <term><varname>Termination=
</varname></term>
3160 <para>Takes a boolean or a termination resistor value in ohm in the range
0…
65535. When
3161 <literal>yes
</literal>, the termination resistor is set to
120 ohm. When
3162 <literal>no
</literal> or
<literal>0</literal> is set, the termination resistor is disabled.
3163 When unset, the kernel's default will be used.
</para>
3167 <term><varname>TripleSampling=
</varname></term>
3169 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
3170 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
3174 <term><varname>BusErrorReporting=
</varname></term>
3176 <para>Takes a boolean. When
<literal>yes
</literal>, reporting of CAN bus errors is activated
3177 (those include single bit, frame format, and bit stuffing errors, unable to send dominant bit,
3178 unable to send recessive bit, bus overload, active error announcement, error occurred on
3179 transmission). When unset, the kernel's default will be used. Note: in case of a CAN bus with a
3180 single CAN device, sending a CAN frame may result in a huge number of CAN bus errors.
</para>
3184 <term><varname>ListenOnly=
</varname></term>
3186 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
3187 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
3188 bit. Listen-only mode is important to debug CAN networks without interfering with the
3189 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
3194 <term><varname>Loopback=
</varname></term>
3196 <para>Takes a boolean. When
<literal>yes
</literal>, loopback mode is enabled. When the
3197 loopback mode is enabled, the interface treats messages transmitted by itself as received
3198 messages. The loopback mode is important to debug CAN networks. When unset, the kernel's
3199 default will be used.
</para>
3203 <term><varname>OneShot=
</varname></term>
3205 <para>Takes a boolean. When
<literal>yes
</literal>, one-shot mode is enabled. When unset,
3206 the kernel's default will be used.
</para>
3210 <term><varname>PresumeAck=
</varname></term>
3212 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will ignore missing CAN
3213 ACKs. When unset, the kernel's default will be used.
</para>
3217 <term><varname>ClassicDataLengthCode=
</varname></term>
3219 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will handle the
4bit data
3220 length code (DLC). When unset, the kernel's default will be used.
</para>
3227 <title>[IPoIB] Section Options
</title>
3228 <para>The [IPoIB] section manages the IP over Infiniband and accepts the following keys:
</para>
3229 <variablelist class='network-directives'
>
3230 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_mode" />
3231 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_umcast" />
3236 <title>[QDisc] Section Options
</title>
3237 <para>The [QDisc] section manages the traffic control queueing discipline (qdisc).
</para>
3239 <variablelist class='network-directives'
>
3241 <term><varname>Parent=
</varname></term>
3243 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
3244 or
<literal>ingress
</literal>. This is mandatory.
</para>
3248 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3253 <title>[NetworkEmulator] Section Options
</title>
3254 <para>The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It
3255 can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP
3256 applications, or limit the bandwidth usage of a particular service to simulate internet connections.
3259 <variablelist class='network-directives'
>
3260 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3261 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3264 <term><varname>DelaySec=
</varname></term>
3266 <para>Specifies the fixed amount of delay to be added to all packets going out of the
3267 interface. Defaults to unset.
</para>
3272 <term><varname>DelayJitterSec=
</varname></term>
3274 <para>Specifies the chosen delay to be added to the packets outgoing to the network
3275 interface. Defaults to unset.
</para>
3280 <term><varname>PacketLimit=
</varname></term>
3282 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
3283 An unsigned integer in the range
0…
4294967294. Defaults to
1000.
</para>
3288 <term><varname>LossRate=
</varname></term>
3290 <para>Specifies an independent loss probability to be added to the packets outgoing from the
3291 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3296 <term><varname>DuplicateRate=
</varname></term>
3298 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
3299 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3306 <title>[TokenBucketFilter] Section Options
</title>
3307 <para>The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter
3310 <variablelist class='network-directives'
>
3311 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3312 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3315 <term><varname>LatencySec=
</varname></term>
3317 <para>Specifies the latency parameter, which specifies the maximum amount of time a
3318 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
3323 <term><varname>LimitBytes=
</varname></term>
3325 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
3326 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
3327 respectively, to the base of
1024. Defaults to unset.
</para>
3332 <term><varname>BurstBytes=
</varname></term>
3334 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
3335 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
3336 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to
3342 <term><varname>Rate=
</varname></term>
3344 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
3345 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
3346 Defaults to unset.
</para>
3351 <term><varname>MPUBytes=
</varname></term>
3353 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
3354 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3355 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to zero.
</para>
3360 <term><varname>PeakRate=
</varname></term>
3362 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
3363 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3364 1000. Defaults to unset.
</para>
3369 <term><varname>MTUBytes=
</varname></term>
3371 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
3372 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
3373 Defaults to unset.
</para>
3380 <title>[PIE] Section Options
</title>
3381 <para>The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral
3382 controller-Enhanced (PIE).
</para>
3384 <variablelist class='network-directives'
>
3385 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3386 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3389 <term><varname>PacketLimit=
</varname></term>
3391 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3392 incoming packets are dropped. An unsigned integer in the range
1…
4294967294. Defaults to unset and
3393 kernel's default is used.
</para>
3400 <title>[FlowQueuePIE] Section Options
</title>
3401 <para>The
<literal>[FlowQueuePIE]
</literal> section manages the queueing discipline
3402 (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).
</para>
3404 <variablelist class='network-directives'
>
3405 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3406 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3409 <term><varname>PacketLimit=
</varname></term>
3411 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3412 incoming packets are dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and
3413 kernel's default is used.
</para>
3420 <title>[StochasticFairBlue] Section Options
</title>
3421 <para>The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue
3424 <variablelist class='network-directives'
>
3425 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3426 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3429 <term><varname>PacketLimit=
</varname></term>
3431 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3432 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3433 kernel's default is used.
</para>
3440 <title>[StochasticFairnessQueueing] Section Options
</title>
3441 <para>The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic
3442 fairness queueing (sfq).
</para>
3444 <variablelist class='network-directives'
>
3445 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3446 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3449 <term><varname>PerturbPeriodSec=
</varname></term>
3451 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
3458 <title>[BFIFO] Section Options
</title>
3459 <para>The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First
3462 <variablelist class='network-directives'
>
3463 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3464 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3467 <term><varname>LimitBytes=
</varname></term>
3469 <para>Specifies the hard limit in bytes on the FIFO buffer size. The size limit prevents overflow
3470 in case the kernel is unable to dequeue packets as quickly as it receives them. When this limit is
3471 reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed
3472 as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3473 kernel default is used.
</para>
3480 <title>[PFIFO] Section Options
</title>
3481 <para>The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out
3484 <variablelist class='network-directives'
>
3485 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3486 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3489 <term><varname>PacketLimit=
</varname></term>
3491 <para>Specifies the hard limit on the number of packets in the FIFO queue. The size limit prevents
3492 overflow in case the kernel is unable to dequeue packets as quickly as it receives them. When this
3493 limit is reached, incoming packets are dropped. An unsigned integer in the range
3494 0…
4294967294. Defaults to unset and kernel's default is used.
</para>
3501 <title>[PFIFOHeadDrop] Section Options
</title>
3502 <para>The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out
3503 Head Drop (pfifo_head_drop).
</para>
3505 <variablelist class='network-directives'
>
3506 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3507 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3510 <term><varname>PacketLimit=
</varname></term>
3512 <para>As in [PFIFO] section.
</para></listitem>
3518 <title>[PFIFOFast] Section Options
</title>
3519 <para>The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast
3520 (pfifo_fast).
</para>
3522 <variablelist class='network-directives'
>
3523 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3524 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3529 <title>[CAKE] Section Options
</title>
3530 <para>The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced
3533 <variablelist class='network-directives'
>
3534 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3535 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3538 <term><varname>Bandwidth=
</varname></term>
3540 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
3541 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
3542 unset and kernel's default is used.
</para>
3547 <term><varname>AutoRateIngress=
</varname></term>
3549 <para>Takes a boolean value. Enables automatic capacity estimation based on traffic arriving
3550 at this qdisc. This is most likely to be useful with cellular links, which tend to change
3551 quality randomly. If this setting is enabled, the
<varname>Bandwidth=
</varname> setting is
3552 used as an initial estimate. Defaults to unset, and the kernel's default is used.
</para>
3557 <term><varname>OverheadBytes=
</varname></term>
3559 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative.
3560 Takes an integer in the range -
64…
256. Defaults to unset and kernel's default is used.
3566 <term><varname>MPUBytes=
</varname></term>
3568 <para>Rounds each packet (including overhead) up to the specified bytes. Takes an integer in
3569 the range
1…
256. Defaults to unset and kernel's default is used.
</para>
3574 <term><varname>CompensationMode=
</varname></term>
3576 <para>Takes one of
<literal>none
</literal>,
<literal>atm
</literal>, or
<literal>ptm
</literal>.
3577 Specifies the compensation mode for overhead calculation. When
<literal>none
</literal>, no
3578 compensation is taken into account. When
<literal>atm
</literal>, enables the compensation for
3579 ATM cell framing, which is normally found on ADSL links. When
<literal>ptm
</literal>, enables
3580 the compensation for PTM encoding, which is normally found on VDSL2 links and uses a
64b/
65b
3581 encoding scheme. Defaults to unset and the kernel's default is used.
</para>
3586 <term><varname>UseRawPacketSize=
</varname></term>
3588 <para>Takes a boolean value. When true, the packet size reported by the Linux kernel will be
3589 used, instead of the underlying IP packet size. Defaults to unset, and the kernel's default
3595 <term><varname>FlowIsolationMode=
</varname></term>
3597 <para>CAKE places packets from different flows into different queues, then packets from each
3598 queue are delivered fairly. This specifies whether the fairness is based on source address,
3599 destination address, individual flows, or any combination of those. The available values are:
3604 <term><option>none
</option></term>
3606 The flow isolation is disabled, and all traffic passes through a single queue.
3610 <term><option>src-host
</option></term>
3612 Flows are defined only by source address. Equivalnet to the
<literal>srchost
</literal>
3613 option for
<command>tc qdisc
</command> command. See also
3614 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3618 <term><option>dst-host
</option></term>
3620 Flows are defined only by destination address. Equivalnet to the
3621 <literal>srchost
</literal> option for
<command>tc qdisc
</command> command. See also
3622 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3626 <term><option>hosts
</option></term>
3628 Flows are defined by source-destination host pairs. Equivalent to the same option for
3629 <command>tc qdisc
</command> command. See also
3630 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3634 <term><option>flows
</option></term>
3636 Flows are defined by the entire
5-tuple of source address, destination address,
3637 transport protocol, source port and destination port. Equivalent to the same option for
3638 <command>tc qdisc
</command> command. See also
3639 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3643 <term><option>dual-src-host
</option></term>
3645 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3646 fairness is applied first over source addresses, then over individual flows. Equivalnet
3647 to the
<literal>dual-srchost
</literal> option for
<command>tc qdisc
</command> command.
3649 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3653 <term><option>dual-dst-host
</option></term>
3655 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3656 fairness is applied first over destination addresses, then over individual flows.
3657 Equivalnet to the
<literal>dual-dsthost
</literal> option for
3658 <command>tc qdisc
</command> command. See also
3659 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3663 <term><option>triple
</option></term>
3665 Flows are defined by the
5-tuple (see
<literal>flows
</literal>), and fairness is
3666 applied over source and destination addresses, and also over individual flows.
3667 Equivalnet to the
<literal>triple-isolate
</literal> option for
3668 <command>tc qdisc
</command> command. See also
3669 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3674 <para>Defaults to unset and the kernel's default is used.
</para>
3679 <term><varname>NAT=
</varname></term>
3681 <para>Takes a boolean value. When true, CAKE performs a NAT lookup before applying
3682 flow-isolation rules, to determine the true addresses and port numbers of the packet, to
3683 improve fairness between hosts inside the NAT. This has no practical effect when
3684 <varname>FlowIsolationMode=
</varname> is
<literal>none
</literal> or
<literal>flows
</literal>,
3685 or if NAT is performed on a different host. Defaults to unset, and the kernel's default is
3691 <term><varname>PriorityQueueingPreset=
</varname></term>
3693 <para>CAKE divides traffic into
<literal>tins
</literal>, and each tin has its own independent
3694 set of flow-isolation queues, bandwidth threshold, and priority. This specifies the preset of
3695 tin profiles. The available values are:
</para>
3699 <term><option>besteffort
</option></term>
3701 Disables priority queueing by placing all traffic in one tin.
3705 <term><option>precedence
</option></term>
3707 Enables priority queueing based on the legacy interpretation of TOS
3708 <literal>Precedence
</literal> field. Use of this preset on the modern Internet is
3713 <term><option>diffserv8
</option></term>
3715 Enables priority queueing based on the Differentiated Service
3716 (
<literal>DiffServ
</literal>) field with eight tins: Background Traffic, High
3717 Throughput, Best Effort, Video Streaming, Low Latency Transactions, Interactive Shell,
3718 Minimum Latency, and Network Control.
3722 <term><option>diffserv4
</option></term>
3724 Enables priority queueing based on the Differentiated Service
3725 (
<literal>DiffServ
</literal>) field with four tins: Background Traffic, Best Effort,
3726 Streaming Media, and Latency Sensitive.
3730 <term><option>diffserv3
</option></term>
3732 Enables priority queueing based on the Differentiated Service
3733 (
<literal>DiffServ
</literal>) field with three tins: Background Traffic, Best Effort,
3734 and Latency Sensitive.
3739 <para>Defaults to unset, and the kernel's default is used.
</para>
3744 <term><varname>FirewallMark=
</varname></term>
3746 <para>Takes an integer in the range
1…
4294967295. When specified, firewall-mark-based
3747 overriding of CAKE's tin selection is enabled. Defaults to unset, and the kernel's default is
3753 <term><varname>Wash=
</varname></term>
3755 <para>Takes a boolean value. When true, CAKE clears the DSCP fields, except for ECN bits, of
3756 any packet passing through CAKE. Defaults to unset, and the kernel's default is used.
</para>
3761 <term><varname>SplitGSO=
</varname></term>
3763 <para>Takes a boolean value. When true, CAKE will split General Segmentation Offload (GSO)
3764 super-packets into their on-the-wire components and dequeue them individually. Defaults to
3765 unset, and the kernel's default is used.
</para>
3773 <title>[ControlledDelay] Section Options
</title>
3774 <para>The [ControlledDelay] section manages the queueing discipline (qdisc) of
3775 controlled delay (CoDel).
</para>
3777 <variablelist class='network-directives'
>
3778 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3779 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3782 <term><varname>PacketLimit=
</varname></term>
3784 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3785 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3786 kernel's default is used.
</para>
3791 <term><varname>TargetSec=
</varname></term>
3793 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3794 Defaults to unset and kernel's default is used.
</para>
3799 <term><varname>IntervalSec=
</varname></term>
3801 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3802 become too stale. Defaults to unset and kernel's default is used.
</para>
3807 <term><varname>ECN=
</varname></term>
3809 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3810 unset and kernel's default is used.
</para>
3815 <term><varname>CEThresholdSec=
</varname></term>
3817 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3818 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3825 <title>[DeficitRoundRobinScheduler] Section Options
</title>
3826 <para>The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round
3827 Robin Scheduler (DRR).
</para>
3829 <variablelist class='network-directives'
>
3830 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3831 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3836 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
3837 <para>The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round
3838 Robin Scheduler (DRR).
</para>
3840 <variablelist class='network-directives'
>
3841 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3842 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3845 <term><varname>QuantumBytes=
</varname></term>
3847 <para>Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves
3848 to the next class. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3849 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to the MTU of the
3858 <title>[EnhancedTransmissionSelection] Section Options
</title>
3859 <para>The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced
3860 Transmission Selection (ETS).
</para>
3862 <variablelist class='network-directives'
>
3863 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3864 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3867 <term><varname>Bands=
</varname></term>
3869 <para>Specifies the number of bands. An unsigned integer in the range
1…
16. This value has to be at
3870 least large enough to cover the strict bands specified through the
<varname>StrictBands=
</varname>
3871 and bandwidth-sharing bands specified in
<varname>QuantumBytes=
</varname>.
</para>
3876 <term><varname>StrictBands=
</varname></term>
3878 <para>Specifies the number of bands that should be created in strict mode. An unsigned integer in
3879 the range
1…
16.
</para>
3884 <term><varname>QuantumBytes=
</varname></term>
3886 <para>Specifies the white-space separated list of quantum used in band-sharing bands. When
3887 suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3888 respectively, to the base of
1024. This setting can be specified multiple times. If an empty
3889 string is assigned, then the all previous assignments are cleared.
</para>
3894 <term><varname>PriorityMap=
</varname></term>
3896 <para>The priority map maps the priority of a packet to a band. The argument is a whitespace
3897 separated list of numbers. The first number indicates which band the packets with priority
0 should
3898 be put to, the second is for priority
1, and so on. There can be up to
16 numbers in the list. If
3899 there are fewer, the default band that traffic with one of the unmentioned priorities goes to is
3900 the last one. Each band number must be in the range
0…
255. This setting can be specified multiple
3901 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
3908 <title>[GenericRandomEarlyDetection] Section Options
</title>
3909 <para>The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random
3910 Early Detection (GRED).
</para>
3912 <variablelist class='network-directives'
>
3913 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3914 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3917 <term><varname>VirtualQueues=
</varname></term>
3919 <para>Specifies the number of virtual queues. Takes an integer in the range
1…
16. Defaults to unset
3920 and kernel's default is used.
</para>
3925 <term><varname>DefaultVirtualQueue=
</varname></term>
3927 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
3928 Defaults to unset and kernel's default is used.
</para>
3933 <term><varname>GenericRIO=
</varname></term>
3935 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
3936 unset and kernel's default is used.
</para>
3943 <title>[FairQueueingControlledDelay] Section Options
</title>
3944 <para>The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing
3945 controlled delay (FQ-CoDel).
</para>
3947 <variablelist class='network-directives'
>
3948 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3949 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3952 <term><varname>PacketLimit=
</varname></term>
3954 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
3955 dropped. Defaults to unset and kernel's default is used.
</para>
3960 <term><varname>MemoryLimitBytes=
</varname></term>
3962 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
3963 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3964 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
3969 <term><varname>Flows=
</varname></term>
3971 <para>Specifies the number of flows into which the incoming packets are classified.
3972 Defaults to unset and kernel's default is used.
</para>
3977 <term><varname>TargetSec=
</varname></term>
3979 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3980 Defaults to unset and kernel's default is used.
</para>
3985 <term><varname>IntervalSec=
</varname></term>
3987 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3988 become too stale. Defaults to unset and kernel's default is used.
</para>
3993 <term><varname>QuantumBytes=
</varname></term>
3995 <para>Specifies the number of bytes used as the
"deficit" in the fair queuing algorithm timespan.
3996 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3997 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
4002 <term><varname>ECN=
</varname></term>
4004 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
4005 unset and kernel's default is used.
</para>
4010 <term><varname>CEThresholdSec=
</varname></term>
4012 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4013 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4020 <title>[FairQueueing] Section Options
</title>
4021 <para>The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing
4024 <variablelist class='network-directives'
>
4025 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4026 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4029 <term><varname>PacketLimit=
</varname></term>
4031 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
4032 dropped. Defaults to unset and kernel's default is used.
</para>
4037 <term><varname>FlowLimit=
</varname></term>
4039 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
4040 unset and kernel's default is used.
</para>
4045 <term><varname>QuantumBytes=
</varname></term>
4047 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
4048 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4049 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
4050 default is used.
</para>
4055 <term><varname>InitialQuantumBytes=
</varname></term>
4057 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
4058 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
4059 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
4060 kernel's default is used.
</para>
4065 <term><varname>MaximumRate=
</varname></term>
4067 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
4068 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
4069 1000. Defaults to unset and kernel's default is used.
</para>
4074 <term><varname>Buckets=
</varname></term>
4076 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
4077 kernel's default is used.
</para>
4082 <term><varname>OrphanMask=
</varname></term>
4084 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
4085 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
4086 kernel's default is used.
</para>
4091 <term><varname>Pacing=
</varname></term>
4093 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
4094 default is used.
</para>
4099 <term><varname>CEThresholdSec=
</varname></term>
4101 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4102 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4109 <title>[TrivialLinkEqualizer] Section Options
</title>
4110 <para>The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link
4111 equalizer (teql).
</para>
4113 <variablelist class='network-directives'
>
4114 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4115 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4118 <term><varname>Id=
</varname></term>
4120 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
4121 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
4122 <constant>max_equalizers=N+
1</constant> option must be loaded before
4123 <command>systemd-networkd
</command> is started.
</para>
4130 <title>[HierarchyTokenBucket] Section Options
</title>
4131 <para>The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token
4132 bucket (htb).
</para>
4134 <variablelist class='network-directives'
>
4135 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4136 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4139 <term><varname>DefaultClass=
</varname></term>
4141 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
4142 to the class. Defaults to unset.
</para>
4147 <term><varname>RateToQuantum=
</varname></term>
4149 <para>Takes an unsigned integer. The DRR quantums are calculated by dividing the value
4150 configured in
<varname>Rate=
</varname> by
<varname>RateToQuantum=
</varname>.
</para>
4157 <title>[HierarchyTokenBucketClass] Section Options
</title>
4158 <para>The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket
4161 <variablelist class='network-directives'
>
4162 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4163 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4166 <term><varname>Priority=
</varname></term>
4168 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
4169 priority field are tried for packets first.
</para>
4174 <term><varname>QuantumBytes=
</varname></term>
4176 <para>Specifies how many bytes to serve from leaf at once. When suffixed with K, M, or G, the
4177 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4183 <term><varname>MTUBytes=
</varname></term>
4185 <para>Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified
4186 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4191 <term><varname>OverheadBytes=
</varname></term>
4193 <para>Takes an unsigned integer which specifies per-packet size overhead used in rate
4194 computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4195 Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4200 <term><varname>Rate=
</varname></term>
4202 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
4203 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
4204 to the base of
1000. This setting is mandatory.
</para>
4209 <term><varname>CeilRate=
</varname></term>
4211 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
4212 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
4213 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
4219 <term><varname>BufferBytes=
</varname></term>
4221 <para>Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed
4222 with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
4223 to the base of
1024.
</para>
4228 <term><varname>CeilBufferBytes=
</varname></term>
4230 <para>Specifies the maximum bytes burst for ceil which can be accumulated during idle period.
4231 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4232 respectively, to the base of
1024.
</para>
4239 <title>[HeavyHitterFilter] Section Options
</title>
4240 <para>The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter
4243 <variablelist class='network-directives'
>
4244 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4245 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4248 <term><varname>PacketLimit=
</varname></term>
4250 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
4251 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
4252 kernel's default is used.
</para>
4259 <title>[QuickFairQueueing] Section Options
</title>
4260 <para>The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing
4263 <variablelist class='network-directives'
>
4264 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4265 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4270 <title>[QuickFairQueueingClass] Section Options
</title>
4271 <para>The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing
4274 <variablelist class='network-directives'
>
4275 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4276 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4279 <term><varname>Weight=
</varname></term>
4281 <para>Specifies the weight of the class. Takes an integer in the range
1…
1023. Defaults to
4282 unset in which case the kernel default is used.
</para>
4287 <term><varname>MaxPacketBytes=
</varname></term>
4289 <para>Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the
4290 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4291 1024. When unset, the kernel default is used.
</para>
4298 <title>[BridgeVLAN] Section Options
</title>
4299 <para>The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the
4300 following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The
4301 <varname>VLANFiltering=
</varname> option has to be enabled, see the [Bridge] section in
4302 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
4304 <variablelist class='network-directives'
>
4306 <term><varname>VLAN=
</varname></term>
4308 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. Takes
4309 an integer in the range
1…
4094.
</para>
4313 <term><varname>EgressUntagged=
</varname></term>
4315 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
4316 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
4317 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
4321 <term><varname>PVID=
</varname></term>
4323 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
4324 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
4325 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
4332 <title>Examples
</title>
4334 <title>Static network configuration
</title>
4336 <programlisting># /etc/systemd/network/
50-static.network
4341 Address=
192.168.0.15/
24
4342 Gateway=
192.168.0.1</programlisting>
4344 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
4345 specified gateway will be used for a default route.
</para>
4349 <title>DHCP on ethernet links
</title>
4351 <programlisting># /etc/systemd/network/
80-dhcp.network
4356 DHCP=yes
</programlisting>
4358 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
4359 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
4363 <title>IPv6 Prefix Delegation
</title>
4365 <programlisting># /etc/systemd/network/
55-ipv6-pd-upstream.network
4370 DHCP=ipv6
</programlisting>
4372 <programlisting># /etc/systemd/network/
56-ipv6-pd-downstream.network
4378 DHCPv6PrefixDelegation=yes
</programlisting>
4380 <para>This will enable DHCPv6-PD on the interface enp1s0 as an upstream interface where the
4381 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
4382 The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network.
4387 <title>A bridge with two enslaved links
</title>
4389 <programlisting># /etc/systemd/network/
25-bridge-static.network
4394 Address=
192.168.0.15/
24
4396 DNS=
192.168.0.1</programlisting>
4398 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
4403 Bridge=bridge0
</programlisting>
4405 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
4410 Bridge=bridge0
</programlisting>
4412 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
4413 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
4414 and network assigned, and a default route via the specified gateway will be
4415 added. The specified DNS server will be added to the global list of DNS resolvers.
4423 # /etc/systemd/network/
20-bridge-slave-interface-vlan.network
4439 EgressUntagged=
300-
400</programlisting>
4441 <para>This overrides the configuration specified in the previous example for the
4442 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
4443 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
4444 untagged when they leave on this interface. Untagged packets which arrive on this
4445 interface will be assigned VLAN ID
42.
</para>
4449 <title>Various tunnels
</title>
4451 <programlisting>/etc/systemd/network/
25-tunnels.network
4462 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
4468 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
4474 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
4480 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
4486 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
4487 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
4491 <title>A bond device
</title>
4493 <programlisting># /etc/systemd/network/
30-bond1.network
4501 <programlisting># /etc/systemd/network/
30-bond1.netdev
4507 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
4509 MACAddress=
52:
54:
00:e9:
64:
41
4515 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
4517 MACAddress=
52:
54:
00:e9:
64:
42
4523 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
4524 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
4525 will be used to acquire an address.
</para>
4529 <title>Virtual Routing and Forwarding (VRF)
</title>
4530 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
4531 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
4532 within the routing table defined during VRF creation. For kernels before
4.8 traffic
4533 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
4535 <programlisting># /etc/systemd/network/
25-vrf.network
4545 <title>MacVTap
</title>
4546 <para>This brings up a network interface
<literal>macvtap-test
</literal>
4547 and attaches it to
<literal>enp0s25
</literal>.
</para>
4548 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
4553 MACVTAP=macvtap-test
4558 <title>A Xfrm interface with physical underlying device.
</title>
4560 <programlisting># /etc/systemd/network/
27-xfrm.netdev
4565 InterfaceId=
7</programlisting>
4567 <programlisting># /etc/systemd/network/
27-eth0.network
4572 Xfrm=xfrm0
</programlisting>
4574 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
4575 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
4576 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
4582 <title>See Also
</title>
4584 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
4585 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
4586 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4587 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4588 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob