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
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
45 processed in lexical order, regardless of the directories in which they live. However, files with
46 identical filenames replace each other. Files in
<filename>/etc/
</filename> have the highest
47 priority, files in
<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
49 a local file if needed. As a special case, an empty file (file size
0) or symlink with the same
50 name pointing to
<filename>/dev/null
</filename> disables the configuration file entirely (it is
53 <para>Along with the network file
<filename>foo.network
</filename>, a
"drop-in" directory
54 <filename>foo.network.d/
</filename> may exist. All files with the suffix
55 <literal>.conf
</literal> from this directory will be merged in the alphanumeric order and parsed
56 after the main file itself has been parsed. This is useful to alter or add configuration settings,
57 without having to modify the main configuration file. Each drop-in file must have appropriate
58 section headers.
</para>
60 <para>In addition to
<filename>/etc/systemd/network
</filename>, drop-in
<literal>.d
</literal>
61 directories can be placed in
<filename>/usr/lib/systemd/network
</filename> or
62 <filename>/run/systemd/network
</filename> directories. Drop-in files in
63 <filename>/etc/
</filename> take precedence over those in
<filename>/run/
</filename> which in turn
64 take precedence over those in
<filename>/usr/lib/
</filename>. Drop-in files under any of these
65 directories take precedence over the main network file wherever located.
</para>
69 <title>[Match] Section Options
</title>
71 <para>The network file contains a [Match] section, which determines if a given network file may
72 be applied to a given device; and a [Network] section specifying how the device should be
73 configured. The first (in lexical order) of the network files that matches a given device is
74 applied, all later files are ignored, even if they match as well.
</para>
76 <para>A network file is said to match a network interface if all matches specified by the [Match]
77 section are satisfied. When a network file does not contain valid settings in [Match] section, then
78 the file will match all interfaces and
<command>systemd-networkd
</command> warns about that. Hint:
79 to avoid the warning and to make it clear that all interfaces shall be matched, add the following:
80 <programlisting>Name=*
</programlisting> The following keys are accepted:
</para>
82 <variablelist class='network-directives'
>
83 <xi:include href=
"systemd.link.xml" xpointer=
"mac-address" />
84 <xi:include href=
"systemd.link.xml" xpointer=
"permanent-mac-address" />
85 <xi:include href=
"systemd.link.xml" xpointer=
"path" />
86 <xi:include href=
"systemd.link.xml" xpointer=
"driver" />
87 <xi:include href=
"systemd.link.xml" xpointer=
"type" />
88 <xi:include href=
"systemd.link.xml" xpointer=
"property" />
91 <term><varname>Name=
</varname></term>
93 <para>A whitespace-separated list of shell-style globs matching the device name, as exposed
94 by the udev property
<literal>INTERFACE
</literal>, or device's alternative names. If the
95 list is prefixed with a
"!", the test is inverted.
</para>
100 <term><varname>WLANInterfaceType=
</varname></term>
102 <para>A whitespace-separated list of wireless network type. Supported values are
103 <literal>ad-hoc
</literal>,
<literal>station
</literal>,
<literal>ap
</literal>,
104 <literal>ap-vlan
</literal>,
<literal>wds
</literal>,
<literal>monitor
</literal>,
105 <literal>mesh-point
</literal>,
<literal>p2p-client
</literal>,
<literal>p2p-go
</literal>,
106 <literal>p2p-device
</literal>,
<literal>ocb
</literal>, and
<literal>nan
</literal>. If the
107 list is prefixed with a
"!", the test is inverted.
</para>
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.
</para>
120 <term><varname>BSSID=
</varname></term>
122 <para>A whitespace-separated list of hardware address of the currently connected wireless
123 LAN. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example in
124 <varname>MACAddress=
</varname>. This option may appear more than once, in which case the
125 lists are merged. If the empty string is assigned to this option, the list is reset.
</para>
129 <xi:include href=
"systemd.link.xml" xpointer=
"host" />
130 <xi:include href=
"systemd.link.xml" xpointer=
"virtualization" />
131 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-command-line" />
132 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-version" />
133 <xi:include href=
"systemd.link.xml" xpointer=
"architecture" />
134 <xi:include href=
"systemd.link.xml" xpointer=
"firmware" />
139 <title>[Link] Section Options
</title>
141 <para>The [Link] section accepts the following keys:
</para>
143 <variablelist class='network-directives'
>
145 <term><varname>MACAddress=
</varname></term>
147 <para>The hardware address to set for the device.
</para>
152 <term><varname>MTUBytes=
</varname></term>
154 <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M,
155 G, are supported and are understood to the base of
1024.
</para>
156 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen below
1280 (the
157 minimum MTU for IPv6) it will automatically be increased to this value.
</para>
162 <term><varname>ARP=
</varname></term>
164 <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol)
165 for this interface is enabled. When unset, the kernel's default will be used.
</para>
166 <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
167 interfaces atop a single lower-level physical interface, which will then only serve as a
168 link/
"bridge" device aggregating traffic to the same physical link and not participate in
169 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
182 <term><varname>AllMulticast=
</varname></term>
184 <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the
185 network. This happens when multicast routing is enabled. Defaults to unset.
</para>
190 <term><varname>Promiscuous=
</varname></term>
192 <para>Takes a boolean. If set to true, promiscuous mode of the interface is enabled. Defaults
194 <para>If this is set to false for the underlying link of a
<literal>passthru
</literal> mode
195 MACVLAN/MACVTAP, the virtual interface will be created with the
<literal>nopromisc
</literal>
201 <term><varname>Unmanaged=
</varname></term>
203 <para>Takes a boolean. When
<literal>yes
</literal>, no attempts are made to bring up or
204 configure matching links, equivalent to when there are no matching network files. Defaults to
205 <literal>no
</literal>.
</para>
206 <para>This is useful for preventing later matching network files from interfering with
207 certain interfaces that are fully controlled by other applications.
</para>
212 <term><varname>Group=
</varname></term>
214 <para>Link groups are similar to port ranges found in managed switches. When network
215 interfaces are added to a numbered group, operations on all the interfaces from that group
216 can be performed at once. Takes an unsigned integer in the range
0…
2147483647. Defaults to
222 <term><varname>RequiredForOnline=
</varname></term>
224 <para>Takes a boolean or a minimum operational state and an optional maximum operational
226 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
227 for possible operational states. When
<literal>yes
</literal>, the network is deemed required
228 when determining whether the system is online (including when running
229 <command>systemd-networkd-wait-online
</command>). When
<literal>no
</literal>, the network is
230 ignored when determining the online state. When a minimum operational state and an optional
231 maximum operational state are set,
<literal>yes
</literal> is implied, and this controls the
232 minimum and maximum operational state required for the network interface to be considered
235 <para>Defaults to
<literal>yes
</literal> when
<varname>ActivationPolicy=
</varname> is not
236 set, or set to
<literal>up
</literal>,
<literal>always-up
</literal>, or
237 <literal>bound
</literal>. Defaults to
<literal>no
</literal> when
238 <varname>ActivationPolicy=
</varname> is set to
<literal>manual
</literal> or
239 <literal>down
</literal>. This is forced to
<literal>no
</literal> when
240 <varname>ActivationPolicy=
</varname> is set to
<literal>always-down
</literal>.
</para>
242 <para>The network will be brought up normally (as configured by
243 <varname>ActivationPolicy=
</varname>), but in the event that there is no address being
244 assigned by DHCP or the cable is not plugged in, the link will simply remain offline and be
245 skipped automatically by
<command>systemd-networkd-wait-online
</command> if
246 <literal>RequiredForOnline=no
</literal>.
</para>
251 <term><varname>RequiredFamilyForOnline=
</varname></term>
253 <para>Takes an address family. When specified, an IP address in the given family is deemed
254 required when determining whether the link is online (including when running
255 <command>systemd-networkd-wait-online
</command>). Takes one of
<literal>ipv4
</literal>,
256 <literal>ipv6
</literal>,
<literal>both
</literal>, or
<literal>any
</literal>. Defaults to
257 <literal>any
</literal>. Note that this option has no effect if
258 <literal>RequiredForOnline=no
</literal>, or if
<literal>RequiredForOnline=
</literal>
259 specifies a minimum operational state below
<literal>degraded
</literal>.
</para>
264 <term><varname>ActivationPolicy=
</varname></term>
266 <para>Specifies the policy for
<command>systemd-networkd
</command> managing the link
267 administrative state. Specifically, this controls how
<command>systemd-networkd
</command>
268 changes the network device's
<literal>IFF_UP
</literal> flag, which is sometimes
269 controlled by system administrators by running e.g.,
270 <command>ip link set dev eth0 up
</command> or
<command>ip link set dev eth0 down
</command>,
271 and can also be changed with
<command>networkctl up eth0
</command> or
272 <command>networkctl down eth0
</command>.
</para>
274 <para>Takes one of
<literal>up
</literal>,
<literal>always-up
</literal>,
275 <literal>manual
</literal>,
<literal>always-down
</literal>,
<literal>down
</literal>,
276 or
<literal>bound
</literal>. When
<literal>manual
</literal>,
277 <command>systemd-networkd
</command> will not change the link's admin state automatically;
278 the system administrator must bring the interface up or down manually, as desired. When
279 <literal>up
</literal> (the default) or
<literal>always-up
</literal>, or
280 <literal>down
</literal> or
<literal>always-down
</literal>,
281 <command>systemd-networkd
</command> will set the link up or down, respectively, when the
282 interface is (re)configured. When
<literal>always-up
</literal> or
283 <literal>always-down
</literal>,
<command>systemd-networkd
</command> will set the link up or
284 down, respectively, any time
<command>systemd-networkd
</command> detects a change in the
285 administrative state. When
<varname>BindCarrier=
</varname> is also set, this is automatically
286 set to
<literal>bound
</literal> and any other value is ignored.
</para>
288 <para>When the policy is set to
<literal>down
</literal> or
<literal>manual
</literal>, the
289 default value of
<varname>RequiredForOnline=
</varname> is
<literal>no
</literal>. When the
290 policy is set to
<literal>always-down
</literal>, the value of
291 <varname>RequiredForOnline=
</varname> forced to
<literal>no
</literal>.
</para>
293 <para>The administrative state is not the same as the carrier state, so using
294 <literal>always-up
</literal> does not mean the link will never lose carrier. The link carrier
295 depends on both the administrative state as well as the network device's physical connection.
296 However, to avoid reconfiguration failures, when using
<literal>always-up
</literal>,
297 <varname>IgnoreCarrierLoss=
</varname> is forced to true.
</para>
304 <title>[SR-IOV] Section Options
</title>
305 <para>The [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to
306 configure several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource
307 into virtual PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV
308 improves north-south network performance (that is, traffic with endpoints outside the host machine)
309 by allowing traffic to bypass the host machine’s network stack.
</para>
311 <variablelist class='network-directives'
>
313 <term><varname>VirtualFunction=
</varname></term>
315 <para>Specifies a Virtual Function (VF), lightweight PCIe function designed solely to move
316 data in and out. Takes an integer in the range
0…
2147483646. This option is compulsory.
322 <term><varname>VLANId=
</varname></term>
324 <para>Specifies VLAN ID of the virtual function. Takes an integer in the range
1…
4095.
</para>
329 <term><varname>QualityOfService=
</varname></term>
331 <para>Specifies quality of service of the virtual function. Takes an integer in the range
332 1…
4294967294.
</para>
337 <term><varname>VLANProtocol=
</varname></term>
339 <para>Specifies VLAN protocol of the virtual function. Takes
<literal>802.1Q
</literal> or
340 <literal>802.1ad
</literal>.
</para>
345 <term><varname>MACSpoofCheck=
</varname></term>
347 <para>Takes a boolean. Controls the MAC spoof checking. When unset, the kernel's default will
353 <term><varname>QueryReceiveSideScaling=
</varname></term>
355 <para>Takes a boolean. Toggle the ability of querying the receive side scaling (RSS)
356 configuration of the virtual function (VF). The VF RSS information like RSS hash key may be
357 considered sensitive on some devices where this information is shared between VF and the
358 physical function (PF). When unset, the kernel's default will be used.
</para>
363 <term><varname>Trust=
</varname></term>
365 <para>Takes a boolean. Allows one to set trust mode of the virtual function (VF). When set, VF
366 users can set a specific feature which may impact security and/or performance. When unset,
367 the kernel's default will be used.
</para>
372 <term><varname>LinkState=
</varname></term>
374 <para>Allows one to set the link state of the virtual function (VF). Takes a boolean or a
375 special value
<literal>auto
</literal>. Setting to
<literal>auto
</literal> means a
376 reflection of the physical function (PF) link state,
<literal>yes
</literal> lets the VF to
377 communicate with other VFs on this host even if the PF link state is down,
378 <literal>no
</literal> causes the hardware to drop any packets sent by the VF. When unset,
379 the kernel's default will be used.
</para>
384 <term><varname>MACAddress=
</varname></term>
386 <para>Specifies the MAC address for the virtual function.
</para>
393 <title>[Network] Section Options
</title>
395 <para>The [Network] section accepts the following keys:
</para>
397 <variablelist class='network-directives'
>
399 <term><varname>Description=
</varname></term>
401 <para>A description of the device. This is only used for presentation purposes.
</para>
406 <term><varname>DHCP=
</varname></term>
408 <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
<literal>yes
</literal>,
409 <literal>no
</literal>,
<literal>ipv4
</literal>, or
<literal>ipv6
</literal>. Defaults to
410 <literal>no
</literal>.
</para>
412 <para>Note that DHCPv6 will by default be triggered by Router Advertisement, if that is
413 enabled, regardless of this parameter. By enabling DHCPv6 support explicitly, the DHCPv6
414 client will be started regardless of the presence of routers on the link, or what flags the
415 routers pass. See
<literal>IPv6AcceptRA=
</literal>.
</para>
417 <para>Furthermore, note that by default the domain name specified through DHCP is not used
418 for name resolution. See option
<option>UseDomains=
</option> below.
</para>
420 <para>See the [DHCPv4] or [DHCPv6] sections below for further configuration options for the
421 DHCP client support.
</para>
426 <term><varname>DHCPServer=
</varname></term>
428 <para>Takes a boolean. If set to
<literal>yes
</literal>, DHCPv4 server will be started.
429 Defaults to
<literal>no
</literal>. Further settings for the DHCP server may be set in the
430 [DHCPServer] section described below.
</para>
435 <term><varname>LinkLocalAddressing=
</varname></term>
437 <para>Enables link-local address autoconfiguration. Accepts
<option>yes
</option>,
438 <option>no
</option>,
<option>ipv4
</option>, and
<option>ipv6
</option>. An IPv6 link-local
439 address is configured when
<option>yes
</option> or
<option>ipv6
</option>. An IPv4 link-local
440 address is configured when
<option>yes
</option> or
<option>ipv4
</option> and when DHCPv4
441 autoconfiguration has been unsuccessful for some time. (IPv4 link-local address
442 autoconfiguration will usually happen in parallel with repeated attempts to acquire a DHCPv4
445 <para>Defaults to
<option>no
</option> when
<varname>KeepMaster=
</varname> or
446 <varname>Bridge=
</varname> is set or when the specified
447 <varname>MACVLAN=
</varname>/
<varname>MACVTAP=
</varname> has
<varname>Mode=passthru
</varname>,
448 or
<option>ipv6
</option> otherwise.
</para>
453 <term><varname>IPv6LinkLocalAddressGenerationMode=
</varname></term>
455 <para>Specifies how IPv6 link local address is generated. Takes one of
456 <literal>eui64
</literal>,
<literal>none
</literal>,
<literal>stable-privacy
</literal> and
457 <literal>random
</literal>. When unset,
<literal>stable-privacy
</literal> is used if
458 <varname>IPv6StableSecretAddress=
</varname> is specified, and if not,
459 <literal>eui64
</literal> is used. Note that if
<varname>LinkLocalAddressing=
</varname> is
460 <literal>no
</literal> or
<literal>ipv4
</literal>, then
461 <varname>IPv6LinkLocalAddressGenerationMode=
</varname> will be ignored. Also, even if
462 <varname>LinkLocalAddressing=
</varname> is
<literal>yes
</literal> or
<literal>ipv6
</literal>,
463 setting
<varname>IPv6LinkLocalAddressGenerationMode=none
</varname>
464 disables to configure an IPv6 link-local address.
</para>
469 <term><varname>IPv6StableSecretAddress=
</varname></term>
471 <para>Takes an IPv6 address. The specified address will be used as a stable secret for
472 generating IPv6 link-local address. If this setting is specified, and
473 <varname>IPv6LinkLocalAddressGenerationMode=
</varname> is unset, then
474 <varname>IPv6LinkLocalAddressGenerationMode=stable-privacy
</varname> is implied.
475 If this setting is not specified, and
<literal>stable-privacy
</literal> is set to
476 <varname>IPv6LinkLocalAddressGenerationMode=
</varname>,
477 then a stable secret address will be generated from the local machine ID and the interface
483 <term><varname>IPv4LLRoute=
</varname></term>
485 <para>Takes a boolean. If set to true, sets up the route needed for non-IPv4LL hosts to
486 communicate with IPv4LL-only hosts. Defaults to false.
</para>
491 <term><varname>DefaultRouteOnDevice=
</varname></term>
493 <para>Takes a boolean. If set to true, sets up the default route bound to the interface.
494 Defaults to false. This is useful when creating routes on point-to-point interfaces. This is
495 equivalent to e.g. the following,
496 <programlisting>ip route add default dev veth99
</programlisting>
498 <programlisting>[Route]
499 Gateway=
0.0.0.0</programlisting></para>
500 <para>Currently, there are no way to specify e.g., the table for the route configured by this
501 setting. To configure the default route with such an additional property, please use the
503 <programlisting>[Route]
505 Table=
1234</programlisting></para>
510 <term><varname>LLMNR=
</varname></term>
512 <para>Takes a boolean or
<literal>resolve
</literal>. When true, enables
513 <ulink url=
"https://tools.ietf.org/html/rfc4795">Link-Local Multicast Name Resolution
</ulink>
514 on the link. When set to
<literal>resolve
</literal>, only resolution is enabled, but not host
515 registration and announcement. Defaults to true. This setting is read by
516 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
522 <term><varname>MulticastDNS=
</varname></term>
524 <para>Takes a boolean or
<literal>resolve
</literal>. When true, enables
525 <ulink url=
"https://tools.ietf.org/html/rfc6762">Multicast DNS
</ulink> support on the link.
526 When set to
<literal>resolve
</literal>, only resolution is enabled, but not host or service
527 registration and announcement. Defaults to false. This setting is read by
528 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
534 <term><varname>DNSOverTLS=
</varname></term>
536 <para>Takes a boolean or
<literal>opportunistic
</literal>. When true, enables
537 <ulink url=
"https://tools.ietf.org/html/rfc7858">DNS-over-TLS
</ulink> support on the link.
538 When set to
<literal>opportunistic
</literal>, compatibility with non-DNS-over-TLS servers is
539 increased, by automatically turning off DNS-over-TLS servers in this case. This option
540 defines a per-interface setting for
541 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
542 global
<varname>DNSOverTLS=
</varname> option. Defaults to unset, and the global setting will
543 be used. This setting is read by
544 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
550 <term><varname>DNSSEC=
</varname></term>
552 <para>Takes a boolean or
<literal>allow-downgrade
</literal>. When true, enables
553 <ulink url=
"https://tools.ietf.org/html/rfc4033">DNSSEC
</ulink> DNS validation support on the
554 link. When set to
<literal>allow-downgrade
</literal>, compatibility with non-DNSSEC capable
555 networks is increased, by automatically turning off DNSSEC in this case. This option defines
556 a per-interface setting for
557 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
558 global
<varname>DNSSEC=
</varname> option. Defaults to unset, and the global setting will be
559 used. This setting is read by
560 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
566 <term><varname>DNSSECNegativeTrustAnchors=
</varname></term>
568 <para>A space-separated list of DNSSEC negative trust anchor domains. If specified and DNSSEC
569 is enabled, look-ups done via the interface's DNS server will be subject to the list of
570 negative trust anchors, and not require authentication for the specified domains, or anything
571 below it. Use this to disable DNSSEC authentication for specific private domains, that cannot
572 be proven valid using the Internet DNS hierarchy. Defaults to the empty list. This setting is
574 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
580 <term><varname>LLDP=
</varname></term>
582 <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol
583 commonly implemented on professional routers and bridges which announces which physical port
584 a system is connected to, as well as other related data. Accepts a boolean or the special
585 value
<literal>routers-only
</literal>. When true, incoming LLDP packets are accepted and a
586 database of all LLDP neighbors maintained. If
<literal>routers-only
</literal> is set only
587 LLDP data of various types of routers is collected and LLDP data about other types of devices
588 ignored (such as stations, telephones and others). If false, LLDP reception is disabled.
589 Defaults to
<literal>routers-only
</literal>. Use
590 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
591 to query the collected neighbor data. LLDP is only available on Ethernet links. See
592 <varname>EmitLLDP=
</varname> below for enabling LLDP packet emission from the local system.
598 <term><varname>EmitLLDP=
</varname></term>
600 <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the
601 special values
<literal>nearest-bridge
</literal>,
<literal>non-tpmr-bridge
</literal> and
602 <literal>customer-bridge
</literal>. Defaults to false, which turns off LLDP packet emission.
603 If not false, a short LLDP packet with information about the local system is sent out in
604 regular intervals on the link. The LLDP packet will contain information about the local
605 hostname, the local machine ID (as stored in
606 <citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
607 and the local interface name, as well as the pretty hostname of the system (as set in
608 <citerefentry><refentrytitle>machine-info
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
609 LLDP emission is only available on Ethernet links. Note that this setting passes data
610 suitable for identification of host to the network and should thus not be enabled on
611 untrusted networks, where such identification data should not be made available. Use this
612 option to permit other systems to identify on which interfaces they are connected to this
613 system. The three special values control propagation of the LLDP packets. The
614 <literal>nearest-bridge
</literal> setting permits propagation only to the nearest connected
615 bridge,
<literal>non-tpmr-bridge
</literal> permits propagation across Two-Port MAC Relays,
616 but not any other bridges, and
<literal>customer-bridge
</literal> permits propagation until
617 a customer bridge is reached. For details about these concepts, see
618 <ulink url=
"https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE
802.1AB-
2016</ulink>.
619 Note that configuring this setting to true is equivalent to
620 <literal>nearest-bridge
</literal>, the recommended and most restricted level of propagation.
621 See
<varname>LLDP=
</varname> above for an option to enable LLDP reception.
</para>
626 <term><varname>BindCarrier=
</varname></term>
628 <para>A link name or a list of link names. When set, controls the behavior of the current
629 link. When all links in the list are in an operational down state, the current link is
630 brought down. When at least one link has carrier, the current interface is brought up.
</para>
632 <para>This forces
<varname>ActivationPolicy=
</varname> to be set to
<literal>bound
</literal>.
638 <term><varname>Address=
</varname></term>
640 <para>A static IPv4 or IPv6 address and its prefix length, separated by a
641 <literal>/
</literal> character. Specify this key more than once to configure several
642 addresses. The format of the address must be as described in
643 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
644 This is a short-hand for an [Address] section only containing an Address key (see below).
645 This option may be specified more than once.
</para>
647 <para>If the specified address is
<literal>0.0.0.0</literal> (for IPv4) or
648 <literal>::
</literal> (for IPv6), a new address range of the requested size is automatically
649 allocated from a system-wide pool of unused ranges. Note that the prefix length must be equal
650 or larger than
8 for IPv4, and
64 for IPv6. The allocated range is checked against all
651 current network interfaces and all known network configuration files to avoid address range
652 conflicts. The default system-wide pool consists of
192.168.0.0/
16,
172.16.0.0/
12 and
653 10.0.0.0/
8 for IPv4, and fd00::/
8 for IPv6. This functionality is useful to manage a large
654 number of dynamically created network interfaces with the same network configuration and
655 automatic address range assignment.
</para>
660 <term><varname>Gateway=
</varname></term>
662 <para>The gateway address, which must be in the format described in
663 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
664 This is a short-hand for a [Route] section only containing a
<varname>Gateway=
</varname> key.
665 This option may be specified more than once.
</para>
670 <term><varname>DNS=
</varname></term>
672 <para>A DNS server address, which must be in the format described in
673 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
674 This option may be specified more than once. Each address can optionally take a port number
675 separated with
<literal>:
</literal>, a network interface name or index separated with
676 <literal>%
</literal>, and a Server Name Indication (SNI) separated with
<literal>#
</literal>.
677 When IPv6 address is specified with a port number, then the address must be in the square
678 brackets. That is, the acceptable full formats are
679 <literal>111.222.333.444:
9953%ifname#example.com
</literal> for IPv4 and
680 <literal>[
1111:
2222::
3333]:
9953%ifname#example.com
</literal> for IPv6. If an empty string is
681 assigned, then the all previous assignments are cleared. This setting is read by
682 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
688 <term><varname>Domains=
</varname></term>
690 <para>A whitespace-separated list of domains which should be resolved using the DNS servers
691 on this link. Each item in the list should be a domain name, optionally prefixed with a tilde
692 (
<literal>~
</literal>). The domains with the prefix are called
"routing-only domains". The
693 domains without the prefix are called
"search domains" and are first used as search suffixes
694 for extending single-label hostnames (hostnames containing no dots) to become fully qualified
695 domain names (FQDNs). If a single-label hostname is resolved on this interface, each of the
696 specified search domains are appended to it in turn, converting it into a fully qualified
697 domain name, until one of them may be successfully resolved.
</para>
699 <para>Both
"search" and
"routing-only" domains are used for routing of DNS queries: look-ups
700 for hostnames ending in those domains (hence also single label names, if any
"search domains"
701 are listed), are routed to the DNS servers configured for this interface. The domain routing
702 logic is particularly useful on multi-homed hosts with DNS servers serving particular private
703 DNS zones on each interface.
</para>
705 <para>The
"routing-only" domain
<literal>~.
</literal> (the tilde indicating definition of a
706 routing domain, the dot referring to the DNS root domain which is the implied suffix of all
707 valid DNS names) has special effect. It causes all DNS traffic which does not match another
708 configured domain routing entry to be routed to DNS servers specified for this interface.
709 This setting is useful to prefer a certain set of DNS servers if a link on which they are
710 connected is available.
</para>
712 <para>This setting is read by
713 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
714 "Search domains" correspond to the
<varname>domain
</varname> and
<varname>search
</varname>
716 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
717 Domain name routing has no equivalent in the traditional glibc API, which has no concept of
718 domain name servers limited to a specific link.
</para>
723 <term><varname>DNSDefaultRoute=
</varname></term>
725 <para>Takes a boolean argument. If true, this link's configured DNS servers are used for
726 resolving domain names that do not match any link's configured
<varname>Domains=
</varname>
727 setting. If false, this link's configured DNS servers are never used for such domains, and
728 are exclusively used for resolving names that match at least one of the domains configured on
729 this link. If not specified defaults to an automatic mode: queries not matching any link's
730 configured domains will be routed to this link if it has no routing-only domains configured.
736 <term><varname>NTP=
</varname></term>
738 <para>An NTP server address (either an IP address, or a hostname). This option may be
739 specified more than once. This setting is read by
740 <citerefentry><refentrytitle>systemd-timesyncd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
746 <term><varname>IPForward=
</varname></term>
748 <para>Configures IP packet forwarding for the system. If enabled, incoming packets on any
749 network interface will be forwarded to any other interfaces according to the routing table.
750 Takes a boolean, or the values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>, which only
751 enable IP packet forwarding for the specified address family. This controls the
752 <filename>net.ipv4.ip_forward
</filename> and
<filename>net.ipv6.conf.all.forwarding
</filename>
753 sysctl options of the network interface (see
754 <ulink url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
755 for details about sysctl options). Defaults to
<literal>no
</literal>.
</para>
757 <para>Note: this setting controls a global kernel option, and does so one way only: if a
758 network that has this setting enabled is set up the global setting is turned on. However,
759 it is never turned off again, even after all networks with this setting enabled are shut
762 <para>To allow IP packet forwarding only between specific network interfaces use a firewall.
768 <term><varname>IPMasquerade=
</varname></term>
770 <para>Configures IP masquerading for the network interface. If enabled, packets forwarded
771 from the network interface will be appear as coming from the local host. Takes one of
772 <literal>ipv4
</literal>,
<literal>ipv6
</literal>,
<literal>both
</literal>, or
773 <literal>no
</literal>. Defaults to
<literal>no
</literal>. If enabled, this automatically sets
774 <varname>IPForward=
</varname> to one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal> or
775 <literal>yes
</literal>.
</para>
776 <para>Note. Any positive boolean values such as
<literal>yes
</literal> or
777 <literal>true
</literal> are now deprecated. Please use one of the values in the above.
</para>
782 <term><varname>IPv6PrivacyExtensions=
</varname></term>
784 <para>Configures use of stateless temporary addresses that change over time (see
785 <ulink url=
"https://tools.ietf.org/html/rfc4941">RFC
4941</ulink>,
786 Privacy Extensions for Stateless Address Autoconfiguration in IPv6). Takes a boolean or the
787 special values
<literal>prefer-public
</literal> and
<literal>kernel
</literal>. When true,
788 enables the privacy extensions and prefers temporary addresses over public addresses. When
789 <literal>prefer-public
</literal>, enables the privacy extensions, but prefers public
790 addresses over temporary addresses. When false, the privacy extensions remain disabled. When
791 <literal>kernel
</literal>, the kernel's default setting will be left in place. Defaults to
792 <literal>no
</literal>.
</para>
797 <term><varname>IPv6AcceptRA=
</varname></term>
799 <para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the
800 interface. If true, RAs are accepted; if false, RAs are ignored. When RAs are accepted, they
801 may trigger the start of the DHCPv6 client if the relevant flags are set in the RA data, or
802 if no routers are found on the link. The default is to disable RA reception for bridge
803 devices or when IP forwarding is enabled, and to enable it otherwise. Cannot be enabled on
804 bond devices and when link local addressing is disabled.
</para>
806 <para>Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA]
807 section, see below.
</para>
810 <ulink url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
811 in the kernel documentation regarding
<literal>accept_ra
</literal>, but note that systemd's
812 setting of
<constant>1</constant> (i.e. true) corresponds to kernel's setting of
813 <constant>2</constant>.
</para>
815 <para>Note that kernel's implementation of the IPv6 RA protocol is always disabled,
816 regardless of this setting. If this option is enabled, a userspace implementation of the IPv6
817 RA protocol is used, and the kernel's own implementation remains disabled, since
818 <command>systemd-networkd
</command> needs to know all details supplied in the advertisements,
819 and these are not available from the kernel if the kernel's own implementation is used.
825 <term><varname>IPv6DuplicateAddressDetection=
</varname></term>
827 <para>Configures the amount of IPv6 Duplicate Address Detection (DAD) probes to send. When
828 unset, the kernel's default will be used.
</para>
833 <term><varname>IPv6HopLimit=
</varname></term>
835 <para>Configures IPv6 Hop Limit. For each router that forwards the packet, the hop limit is
836 decremented by
1. When the hop limit field reaches zero, the packet is discarded. When unset,
837 the kernel's default will be used.
</para>
842 <term><varname>IPv4AcceptLocal=
</varname></term>
844 <para>Takes a boolean. Accept packets with local source addresses. In combination with
845 suitable routing, this can be used to direct packets between two local interfaces over the
846 wire and have them accepted properly. When unset, the kernel's default will be used.
</para>
851 <term><varname>IPv4RouteLocalnet=
</varname></term>
853 <para>Takes a boolean. When true, the kernel does not consider loopback addresses as martian
854 source or destination while routing. This enables the use of
127.0.0.0/
8 for local routing
855 purposes. When unset, the kernel's default will be used.
</para>
860 <term><varname>IPv4ProxyARP=
</varname></term>
862 <para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one
863 host, usually a router, answers ARP requests intended for another machine. By
"faking" its
864 identity, the router accepts responsibility for routing packets to the
"real" destination.
865 See
<ulink url=
"https://tools.ietf.org/html/rfc1027">RFC
1027</ulink>. When unset, the
866 kernel's default will be used.
</para>
871 <term><varname>IPv6ProxyNDP=
</varname></term>
873 <para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery Protocol)
874 is a technique for IPv6 to allow routing of addresses to a different destination when peers
875 expect them to be present on a certain physical link. In this case a router answers Neighbour
876 Advertisement messages intended for another machine by offering its own MAC address as
877 destination. Unlike proxy ARP for IPv4, it is not enabled globally, but will only send
878 Neighbour Advertisement messages for addresses in the IPv6 neighbor proxy table, which can
879 also be shown by
<command>ip -
6 neighbour show proxy
</command>. systemd-networkd will control
880 the per-interface `proxy_ndp` switch for each configured interface depending on this option.
881 When unset, the kernel's default will be used.
</para>
886 <term><varname>IPv6ProxyNDPAddress=
</varname></term>
888 <para>An IPv6 address, for which Neighbour Advertisement messages will be proxied. This
889 option may be specified more than once. systemd-networkd will add the
890 <varname>IPv6ProxyNDPAddress=
</varname> entries to the kernel's IPv6 neighbor proxy table.
891 This setting implies
<varname>IPv6ProxyNDP=yes
</varname> but has no effect if
892 <varname>IPv6ProxyNDP=
</varname> has been set to false. When unset, the kernel's default will
898 <term><varname>IPv6SendRA=
</varname></term>
900 <para>Whether to enable or disable Router Advertisement sending on a link. Takes a boolean
901 value. When enabled, prefixes configured in [IPv6Prefix] sections and routes configured in
902 the [IPv6RoutePrefix] sections are distributed as defined in the [IPv6SendRA] section. If
903 <varname>DHCPPrefixDelegation=
</varname> is enabled, then the delegated prefixes are also
904 distributed. See
<varname>DCHPPrefixDelegation=
</varname> setting and the [IPv6SendRA],
905 [IPv6Prefix], [IPv6RoutePrefix], and [DHCPPrefixDelegation] sections for more configuration
911 <term><varname>DHCPPrefixDelegation=
</varname></term>
913 <para>Takes a boolean value. When enabled, requests subnet prefixes acquired by a DHCPv6
914 client, or by a DHCPv4 client through the
6RD option configured on another link. By default,
915 an address within each delegated prefix will be assigned, and the prefixes will be announced
916 through IPv6 Router Advertisement when
<varname>IPv6SendRA=
</varname> is enabled. Such
917 default settings can be configured in the [DHCPPrefixDelegation] section. Defaults to
923 <term><varname>IPv6MTUBytes=
</varname></term>
925 <para>Configures IPv6 maximum transmission unit (MTU). An integer greater than or equal to
926 1280 bytes. When unset, the kernel's default will be used.
</para>
931 <term><varname>KeepMaster=
</varname></term>
933 <para>Takes a boolean value. When enabled, the current master interface index will not be
934 changed, and
<varname>BatmanAdvanced=
</varname>,
<varname>Bond=
</varname>,
935 <varname>Bridge=
</varname>, and
<varname>VRF=
</varname> settings are ignored. This may be
936 useful when a netdev with a master interface is created by another program, e.g.
937 <citerefentry><refentrytitle>systemd-nspawn
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
938 Defaults to false.
</para>
943 <term><varname>BatmanAdvanced=
</varname></term>
944 <term><varname>Bond=
</varname></term>
945 <term><varname>Bridge=
</varname></term>
946 <term><varname>VRF=
</varname></term>
948 <para>The name of the B.A.T.M.A.N. Advanced, bond, bridge, or VRF interface to add the link
950 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
956 <term><varname>IPoIB=
</varname></term>
957 <term><varname>IPVLAN=
</varname></term>
958 <term><varname>IPVTAP=
</varname></term>
959 <term><varname>L2TP=
</varname></term>
960 <term><varname>MACsec=
</varname></term>
961 <term><varname>MACVLAN=
</varname></term>
962 <term><varname>MACVTAP=
</varname></term>
963 <term><varname>Tunnel=
</varname></term>
964 <term><varname>VLAN=
</varname></term>
965 <term><varname>VXLAN=
</varname></term>
966 <term><varname>Xfrm=
</varname></term>
968 <para>The name of an IPoIB, IPVLAN, IPVTAP, L2TP, MACsec, MACVLAN, MACVTAP, tunnel, VLAN,
969 VXLAN, or Xfrm to be created on the link. See
970 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
971 This option may be specified more than once.
</para>
976 <term><varname>ActiveSlave=
</varname></term>
978 <para>Takes a boolean. Specifies the new active slave. The
<literal>ActiveSlave=
</literal>
979 option is only valid for following modes:
<literal>active-backup
</literal>,
980 <literal>balance-alb
</literal>, and
<literal>balance-tlb
</literal>. Defaults to false.
</para>
985 <term><varname>PrimarySlave=
</varname></term>
987 <para>Takes a boolean. Specifies which slave is the primary device. The specified device will
988 always be the active slave while it is available. Only when the primary is off-line will
989 alternate devices be used. This is useful when one slave is preferred over another, e.g.
990 when one slave has higher throughput than another. The
<literal>PrimarySlave=
</literal>
991 option is only valid for following modes:
<literal>active-backup
</literal>,
992 <literal>balance-alb
</literal>, and
<literal>balance-tlb
</literal>. Defaults to false.
</para>
997 <term><varname>ConfigureWithoutCarrier=
</varname></term>
999 <para>Takes a boolean. Allows networkd to configure a specific link even if it has no
1000 carrier. Defaults to false. If enabled, and the
<varname>IgnoreCarrierLoss=
</varname> setting
1001 is not explicitly set, then it is enabled as well.
</para>
1006 <term><varname>IgnoreCarrierLoss=
</varname></term>
1008 <para>Takes a boolean or a timespan. When true, networkd retains both the static and dynamic
1009 configuration of the interface even if its carrier is lost. When a timespan is specified,
1010 networkd waits for the specified timespan, and ignores the carrier loss if the link regain
1011 its carrier within the timespan. Setting a finite timespan may be useful for a wireless
1012 interface connecting to a network which has multiple access points with the same SSID, or an
1013 interface which is reset on changing MTU. When unset, the value specified with
1014 <varname>ConfigureWithoutCarrier=
</varname> is used.
</para>
1016 <para>When
<varname>ActivationPolicy=
</varname> is set to
<literal>always-up
</literal>, this
1017 is forced to
<literal>true
</literal>.
1023 <term><varname>KeepConfiguration=
</varname></term>
1025 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
1026 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
1027 will not drop static addresses and routes on starting up process. When set to
1028 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
1029 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
1030 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
1031 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
1032 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
1033 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
1034 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
<literal>no
</literal>.
1042 <title>[Address] Section Options
</title>
1044 <para>An [Address] section accepts the following keys. Specify several [Address] sections to
1045 configure several addresses.
</para>
1047 <variablelist class='network-directives'
>
1049 <term><varname>Address=
</varname></term>
1051 <para>As in the [Network] section. This setting is mandatory. Each [Address] section can
1052 contain one
<varname>Address=
</varname> setting.
</para>
1057 <term><varname>Peer=
</varname></term>
1059 <para>The peer address in a point-to-point connection. Accepts the same format as the
1060 <varname>Address=
</varname> setting.
</para>
1065 <term><varname>Broadcast=
</varname></term>
1067 <para>Takes an IPv4 address or boolean value. The address must be in the format described in
1068 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
1069 If set to true, then the IPv4 broadcast address will be derived from the
1070 <varname>Address=
</varname> setting. If set to false, then the broadcast address will not be
1071 set. Defaults to true, except for wireguard interfaces, where it default to false.
</para>
1076 <term><varname>Label=
</varname></term>
1078 <para>Specifies the label for the IPv4 address. The label must be a
7-bit ASCII string with
1079 a length of
1…
15 characters. Defaults to unset.
</para>
1084 <term><varname>PreferredLifetime=
</varname></term>
1086 <para>Allows the default
"preferred lifetime" of the address to be overridden. Only three
1087 settings are accepted:
<literal>forever
</literal>,
<literal>infinity
</literal>, which is the
1088 default and means that the address never expires, and
<literal>0</literal>, which means that
1089 the address is considered immediately
"expired" and will not be used, unless explicitly
1090 requested. A setting of
<option>PreferredLifetime=
0</option> is useful for addresses which
1091 are added to be used only by a specific application, which is then configured to use them
1097 <term><varname>Scope=
</varname></term>
1099 <para>The scope of the address, which can be
<literal>global
</literal> (valid everywhere on
1100 the network, even through a gateway),
<literal>link
</literal> (only valid on this device,
1101 will not traverse a gateway) or
<literal>host
</literal> (only valid within the device itself,
1102 e.g.
127.0.0.1) or an integer in the range
0…
255. Defaults to
<literal>global
</literal>.
1108 <term><varname>RouteMetric=
</varname></term>
1110 <para>The metric of the prefix route, which is pointing to the subnet of the configured IP
1111 address, taking the configured prefix length into account. Takes an unsigned integer in the
1112 range
0…
4294967295. When unset or set to
0, the kernel's default value is used. This
1113 setting will be ignored when
<varname>AddPrefixRoute=
</varname> is false.
</para>
1118 <term><varname>HomeAddress=
</varname></term>
1120 <para>Takes a boolean. Designates this address the
"home address" as defined in
1121 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>. Supported only on IPv6.
1122 Defaults to false.
</para>
1127 <term><varname>DuplicateAddressDetection=
</varname></term>
1129 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
<literal>both
</literal>,
1130 or
<literal>none
</literal>. When
<literal>ipv4
</literal>, performs IPv4 Address Conflict
1131 Detection. See
<ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>.
1132 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
1133 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>. Defaults to
1134 <literal>ipv6
</literal>.
</para>
1139 <term><varname>ManageTemporaryAddress=
</varname></term>
1141 <para>Takes a boolean. If true the kernel manage temporary addresses created from this one as
1142 template on behalf of Privacy Extensions
1143 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become active,
1144 the use_tempaddr sysctl setting has to be set to a value greater than zero. The given address
1145 needs to have a prefix length of
64. This flag allows using privacy extensions in a manually
1146 configured network, just like if stateless auto-configuration was active. Defaults to false.
1152 <term><varname>AddPrefixRoute=
</varname></term>
1154 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
1155 Defaults to true.
</para>
1160 <term><varname>AutoJoin=
</varname></term>
1162 <para>Takes a boolean. Joining multicast group on ethernet level via
1163 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
1164 IGMP snooping since the switch would not replicate multicast packets on ports that did not
1165 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
1166 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
1167 that enables then to do the required join. By extending ip address command with option
1168 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
1169 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
1170 Defaults to
<literal>no
</literal>.
</para>
1177 <title>[Neighbor] Section Options
</title>
1179 <para>A [Neighbor] section accepts the following keys. The neighbor section adds a permanent,
1180 static entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the
1181 links matched for the network. Specify several [Neighbor] sections to configure several static
1184 <variablelist class='network-directives'
>
1186 <term><varname>Address=
</varname></term>
1188 <para>The IP address of the neighbor.
</para>
1193 <term><varname>LinkLayerAddress=
</varname></term>
1195 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1202 <title>[IPv6AddressLabel] Section Options
</title>
1204 <para>An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel]
1205 sections to configure several address labels. IPv6 address labels are used for address selection.
1206 See
<ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>. Precedence is managed by
1207 userspace, and only the label itself is stored in the kernel.
</para>
1209 <variablelist class='network-directives'
>
1211 <term><varname>Label=
</varname></term>
1213 <para>The label for the prefix, an unsigned integer in the range
0…
4294967294.
0xffffffff is
1214 reserved. This setting is mandatory.
</para>
1219 <term><varname>Prefix=
</varname></term>
1221 <para>IPv6 prefix is an address with a prefix length, separated by a slash
1222 <literal>/
</literal> character. This setting is mandatory.
</para>
1229 <title>[RoutingPolicyRule] Section Options
</title>
1231 <para>An [RoutingPolicyRule] section accepts the following settings. Specify several
1232 [RoutingPolicyRule] sections to configure several rules.
</para>
1234 <variablelist class='network-directives'
>
1236 <term><varname>TypeOfService=
</varname></term>
1238 <para>Takes a number between
0 and
255 that specifies the type of service to match.
</para>
1243 <term><varname>From=
</varname></term>
1245 <para>Specifies the source address prefix to match. Possibly followed by a slash and the
1246 prefix length.
</para>
1251 <term><varname>To=
</varname></term>
1253 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the
1254 prefix length.
</para>
1259 <term><varname>FirewallMark=
</varname></term>
1261 <para>Specifies the iptables firewall mark value to match (a number in the range
1262 1…
4294967295). Optionally, the firewall mask (also a number between
1…
4294967295) can be
1263 suffixed with a slash (
<literal>/
</literal>), e.g.,
<literal>7/
255</literal>.
</para>
1268 <term><varname>Table=
</varname></term>
1270 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes
1271 one of predefined names
<literal>default
</literal>,
<literal>main
</literal>, and
1272 <literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname> in
1273 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1274 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1279 <term><varname>Priority=
</varname></term>
1281 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an integer in the
1282 range
0…
4294967295. Higher number means lower priority, and rules get processed in order of
1283 increasing number. Defaults to unset, and the kernel will pick a value dynamically.
</para>
1288 <term><varname>IncomingInterface=
</varname></term>
1290 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches
1291 packets originating from this host.
</para>
1296 <term><varname>OutgoingInterface=
</varname></term>
1298 <para>Specifies the outgoing device to match. The outgoing interface is only available for
1299 packets originating from local sockets that are bound to a device.
</para>
1304 <term><varname>SourcePort=
</varname></term>
1306 <para>Specifies the source IP port or IP port range match in forwarding information base
1307 (FIB) rules. A port range is specified by the lower and upper port separated by a dash.
1308 Defaults to unset.
</para>
1313 <term><varname>DestinationPort=
</varname></term>
1315 <para>Specifies the destination IP port or IP port range match in forwarding information base
1316 (FIB) rules. A port range is specified by the lower and upper port separated by a dash.
1317 Defaults to unset.
</para>
1322 <term><varname>IPProtocol=
</varname></term>
1324 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP
1325 protocol name such as
<literal>tcp
</literal>,
<literal>udp
</literal> or
1326 <literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
1327 <literal>tcp
</literal> or
<literal>17</literal> for
<literal>udp
</literal>. Defaults to unset.
1333 <term><varname>InvertRule=
</varname></term>
1335 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1340 <term><varname>Family=
</varname></term>
1342 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1343 <literal>both
</literal>. By default, the address family is determined by the address
1344 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1345 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1346 <literal>ipv4
</literal>.
</para>
1351 <term><varname>User=
</varname></term>
1353 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1359 <term><varname>SuppressPrefixLength=
</varname></term>
1361 <para>Takes a number
<replaceable>N
</replaceable> in the range
0…
128 and rejects routing
1362 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1368 <term><varname>SuppressInterfaceGroup=
</varname></term>
1370 <para>Takes an integer in the range
0…
2147483647 and rejects routing decisions that have
1371 an interface with the same group id. It has the same meaning as
1372 <option>suppress_ifgroup
</option> in
<command>ip rule
</command>. Defaults to unset.
</para>
1377 <term><varname>Type=
</varname></term>
1379 <para>Specifies Routing Policy Database (RPDB) rule type. Takes one of
1380 <literal>blackhole
</literal>,
<literal>unreachable
</literal> or
<literal>prohibit
</literal>.
1388 <title>[NextHop] Section Options
</title>
1390 <para>The [NextHop] section is used to manipulate entries in the kernel's
"nexthop" tables. The
1391 [NextHop] section accepts the following settings. Specify several [NextHop] sections to configure
1392 several hops.
</para>
1394 <variablelist class='network-directives'
>
1396 <term><varname>Id=
</varname></term>
1398 <para>The id of the next hop. Takes an integer in the range
1…
4294967295. If unspecified,
1399 then automatically chosen by kernel.
</para>
1404 <term><varname>Gateway=
</varname></term>
1406 <para>As in the [Network] section.
</para>
1411 <term><varname>Family=
</varname></term>
1413 <para>Takes one of the special values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>.
1414 By default, the family is determined by the address specified in
1415 <varname>Gateway=
</varname>. If
<varname>Gateway=
</varname> is not specified, then defaults
1416 to
<literal>ipv4
</literal>.
</para>
1421 <term><varname>OnLink=
</varname></term>
1423 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1424 reachable directly by the current machine (i.e., attached to the local network), so that we
1425 can insert the nexthop in the kernel table without it being complained about. Defaults to
1426 <literal>no
</literal>.
</para>
1431 <term><varname>Blackhole=
</varname></term>
1433 <para>Takes a boolean. If enabled, packets to the corresponding routes are discarded
1434 silently, and
<varname>Gateway=
</varname> cannot be specified. Defaults to
1435 <literal>no
</literal>.
</para>
1440 <term><varname>Group=
</varname></term>
1442 <para>Takes a whitespace separated list of nexthop IDs. Each ID must be in the range
1443 1…
4294967295. Optionally, each nexthop ID can take a weight after a colon
1444 (
<literal><replaceable>id
</replaceable><optional>:
<replaceable>weight
</replaceable></optional></literal>).
1445 The weight must be in the range
1…
255. If the weight is not specified, then it is assumed
1446 that the weight is
1. This setting cannot be specified with
<varname>Gateway=
</varname>,
1447 <varname>Family=
</varname>,
<varname>Blackhole=
</varname>. This setting can be specified
1448 multiple times. If an empty string is assigned, then the all previous assignments are
1449 cleared. Defaults to unset.
</para>
1456 <title>[Route] Section Options
</title>
1458 <para>The [Route] section accepts the following settings. Specify several [Route] sections to
1459 configure several routes.
</para>
1461 <variablelist class='network-directives'
>
1463 <term><varname>Gateway=
</varname></term>
1465 <para>Takes the gateway address or the special values
<literal>_dhcp4
</literal> and
1466 <literal>_ipv6ra
</literal>. If
<literal>_dhcp4
</literal> or
<literal>_ipv6ra
</literal> is
1467 set, then the gateway address provided by DHCPv4 or IPv6 RA is used.
</para>
1472 <term><varname>GatewayOnLink=
</varname></term>
1474 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1475 reachable directly by the current machine (i.e., attached to the local network), so that we
1476 can insert the route in the kernel table without it being complained about. Defaults to
1477 <literal>no
</literal>.
</para>
1482 <term><varname>Destination=
</varname></term>
1484 <para>The destination prefix of the route. Possibly followed by a slash and the prefix
1485 length. If omitted, a full-length host route is assumed.
</para>
1490 <term><varname>Source=
</varname></term>
1492 <para>The source prefix of the route. Possibly followed by a slash and the prefix length. If
1493 omitted, a full-length host route is assumed.
</para>
1498 <term><varname>Metric=
</varname></term>
1500 <para>The metric of the route. Takes an unsigned integer in the range
0…
4294967295. Defaults
1501 to unset, and the kernel's default will be used.
</para>
1506 <term><varname>IPv6Preference=
</varname></term>
1508 <para>Specifies the route preference as defined in
1509 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink> for Router Discovery
1510 messages. Which can be one of
<literal>low
</literal> the route has a lowest priority,
1511 <literal>medium
</literal> the route has a default priority or
<literal>high
</literal> the
1512 route has a highest priority.
</para>
1517 <term><varname>Scope=
</varname></term>
1519 <para>The scope of the IPv4 route, which can be
<literal>global
</literal>,
1520 <literal>site
</literal>,
<literal>link
</literal>,
<literal>host
</literal>, or
1521 <literal>nowhere
</literal>:
</para>
1524 <para><literal>global
</literal> means the route can reach hosts more than one hop away.
1529 <para><literal>site
</literal> means an interior route in the local autonomous system.
1534 <para><literal>link
</literal> means the route can only reach hosts on the local network
1535 (one hop away).
</para>
1539 <para><literal>host
</literal> means the route will not leave the local machine (used for
1540 internal addresses like
127.0.0.1).
</para>
1544 <para><literal>nowhere
</literal> means the destination doesn't exist.
</para>
1548 <para>For IPv4 route, defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
1549 <literal>local
</literal> or
<literal>nat
</literal>, and
<literal>link
</literal> if
1550 <varname>Type=
</varname> is
<literal>broadcast
</literal>,
<literal>multicast
</literal>,
1551 <literal>anycast
</literal>, or direct
<literal>unicast
</literal> routes. In other cases,
1552 defaults to
<literal>global
</literal>. The value is not used for IPv6.
</para>
1557 <term><varname>PreferredSource=
</varname></term>
1559 <para>The preferred source address of the route. The address must be in the format described
1561 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
1567 <term><varname>Table=
</varname></term>
1569 <para>The table identifier for the route. Takes one of predefined names
1570 <literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>, and names
1571 defined in
<varname>RouteTable=
</varname> in
1572 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1573 or a number between
1 and
4294967295. The table can be retrieved using
1574 <command>ip route show table
<replaceable>num
</replaceable></command>. If unset and
1575 <varname>Type=
</varname> is
<literal>local
</literal>,
<literal>broadcast
</literal>,
1576 <literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1577 In other cases, defaults to
<literal>main
</literal>.
</para>
1582 <term><varname>Protocol=
</varname></term>
1584 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special
1585 values
<literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1586 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1592 <term><varname>Type=
</varname></term>
1594 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1595 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1596 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1597 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1598 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e.
1599 a route indicating the path to take to a destination network address. If
1600 <literal>blackhole
</literal>, packets to the defined route are discarded silently. If
1601 <literal>unreachable
</literal>, packets to the defined route are discarded and the ICMP
1602 message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets to the
1603 defined route are discarded and the ICMP message
"Communication Administratively Prohibited"
1604 is generated. If
<literal>throw
</literal>, route lookup in the current routing table will
1605 fail and the route selection process will return to Routing Policy Database (RPDB). Defaults
1606 to
<literal>unicast
</literal>.
</para>
1611 <term><varname>InitialCongestionWindow=
</varname></term>
1613 <para>The TCP initial congestion window is used during the start of a TCP connection.
1614 During the start of a TCP session, when a client requests a resource, the server's initial
1615 congestion window determines how many packets will be sent during the initial burst of data
1616 without waiting for acknowledgement. Takes a number between
1 and
1023. Note that
100 is
1617 considered an extremely large value for this option. When unset, the kernel's default
1618 (typically
10) will be used.
</para>
1623 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1625 <para>The TCP initial advertised receive window is the amount of receive data (in bytes)
1626 that can initially be buffered at one time on a connection. The sending host can send only
1627 that amount of data before waiting for an acknowledgment and window update from the
1628 receiving host. Takes a number between
1 and
1023. Note that
100 is considered an extremely
1629 large value for this option. When unset, the kernel's default will be used.
</para>
1634 <term><varname>QuickAck=
</varname></term>
1636 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the
1637 kernel's default will be used.
</para>
1642 <term><varname>FastOpenNoCookie=
</varname></term>
1644 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1645 When unset, the kernel's default will be used.
</para>
1650 <term><varname>TTLPropagate=
</varname></term>
1652 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1653 When unset, the kernel's default will be used.
</para>
1658 <term><varname>MTUBytes=
</varname></term>
1660 <para>The maximum transmission unit in bytes to set for the route. The usual suffixes K, M,
1661 G, are supported and are understood to the base of
1024.
</para>
1666 <term><varname>TCPAdvertisedMaximumSegmentSize=
</varname></term>
1668 <para>Specifies the Path MSS (in bytes) hints given on TCP layer. The usual suffixes K, M, G,
1669 are supported and are understood to the base of
1024. An unsigned integer in the range
1670 1…
4294967294. When unset, the kernel's default will be used.
</para>
1675 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1677 <para>Configures multipath route. Multipath routing is the technique of using multiple
1678 alternative paths through a network. Takes gateway address. Optionally, takes a network
1679 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for this
1680 multipath route separated with whitespace. This setting can be specified multiple times. If
1681 an empty string is assigned, then the all previous assignments are cleared.
</para>
1686 <term><varname>NextHop=
</varname></term>
1688 <para>Specifies the nexthop id. Takes an unsigned integer in the range
1…
4294967295. If set,
1689 the corresponding [NextHop] section must be configured. Defaults to unset.
</para>
1696 <title>[DHCPv4] Section Options
</title>
1698 <para>The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the
1699 <varname>DHCP=
</varname> setting described above:
</para>
1701 <variablelist class='network-directives'
>
1703 <!-- DHCP packet contents -->
1706 <term><varname>SendHostname=
</varname></term>
1708 <para>When true (the default), the machine's hostname (or the value specified with
1709 <varname>Hostname=
</varname>, described below) will be sent to the DHCP server. Note that the
1710 hostname must consist only of
7-bit ASCII lower-case characters and no spaces or dots, and be
1711 formatted as a valid DNS domain name. Otherwise, the hostname is not sent even if this option
1717 <term><varname>Hostname=
</varname></term>
1719 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's
1720 hostname. Note that the specified hostname must consist only of
7-bit ASCII lower-case
1721 characters and no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1726 <term><varname>MUDURL=
</varname></term>
1728 <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent
1729 to the DHCPv4 server. Takes a URL of length up to
255 characters. A superficial verification
1730 that the string is a valid URL will be performed. DHCPv4 clients are intended to have at most
1731 one MUD URL associated with them. See
1732 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
</para>
1734 <para>MUD is an embedded software standard defined by the IETF that allows IoT device makers
1735 to advertise device specifications, including the intended communication patterns for their
1736 device when it connects to the network. The network can then use this to author a
1737 context-specific access policy, so the device functions only within those parameters.
</para>
1742 <term><varname>ClientIdentifier=
</varname></term>
1744 <para>The DHCPv4 client identifier to use. Takes one of
<option>mac
</option>,
1745 <option>duid
</option> or
<option>duid-only
</option>. If set to
<option>mac
</option>, the
1746 MAC address of the link is used. If set to
<option>duid
</option>, an RFC4361-compliant Client
1747 ID, which is the combination of IAID and DUID (see below), is used. If set to
1748 <option>duid-only
</option>, only DUID is used, this may not be RFC compliant, but some setups
1749 may require to use this. Defaults to
<option>duid
</option>.
</para>
1754 <term><varname>VendorClassIdentifier=
</varname></term>
1756 <para>The vendor class identifier used to identify vendor type and configuration.
</para>
1761 <term><varname>UserClass=
</varname></term>
1763 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or
1764 applications it represents. The information contained in this option is a string that
1765 represents the user class of which the client is a member. Each class sets an identifying
1766 string of information to be used by the DHCP service to classify clients. Takes a
1767 whitespace-separated list of strings.
</para>
1772 <term><varname>DUIDType=
</varname></term>
1774 <para>Override the global
<varname>DUIDType=
</varname> setting for this network. See
1775 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1776 for a description of possible values.
</para>
1781 <term><varname>DUIDRawData=
</varname></term>
1783 <para>Override the global
<varname>DUIDRawData=
</varname> setting for this network. See
1784 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1785 for a description of possible values.
</para>
1790 <term><varname>IAID=
</varname></term>
1792 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned
1798 <term><varname>Anonymize=
</varname></term>
1800 <para>Takes a boolean. When true, the options sent to the DHCP server will follow the
1801 <ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink> (Anonymity Profiles for
1802 DHCP Clients) to minimize disclosure of identifying information. Defaults to false.
</para>
1804 <para>This option should only be set to true when
<varname>MACAddressPolicy=
</varname> is set
1805 to
<option>random
</option> (see
1806 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
1809 <para>When true,
<varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1810 <varname>VendorClassIdentifier=
</varname>,
<varname>UserClass=
</varname>,
1811 <varname>RequestOptions=
</varname>,
<varname>SendOption=
</varname>,
1812 <varname>SendVendorOption=
</varname>, and
<varname>MUDURL=
</varname> are ignored.
</para>
1814 <para>With this option enabled DHCP requests will mimic those generated by Microsoft
1815 Windows, in order to reduce the ability to fingerprint and recognize installations. This
1816 means DHCP request sizes will grow and lease data will be more comprehensive than normally,
1817 though most of the requested data is not actually used.
</para>
1822 <term><varname>RequestOptions=
</varname></term>
1824 <para>Sets request options to be sent to the server in the DHCPv4 request options list. A
1825 whitespace-separated list of integers in the range
1…
254. Defaults to unset.
</para>
1830 <term><varname>SendOption=
</varname></term>
1832 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data
1833 type and data separated with a colon
1834 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1835 The option number must be an integer in the range
1…
254. The type takes one of
1836 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1837 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1838 string may be escaped using
1839 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1840 escapes
</ulink>. This setting can be specified multiple times. If an empty string is
1841 specified, then all options specified earlier are cleared. Defaults to unset.
</para>
1846 <term><varname>SendVendorOption=
</varname></term>
1848 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data
1849 type and data separated with a colon
1850 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1851 The option number must be an integer in the range
1…
254. The type takes one of
1852 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1853 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1854 string may be escaped using
1855 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1856 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1857 then all options specified earlier are cleared. Defaults to unset.
</para>
1862 <term><varname>IPServiceType=
</varname></term>
1864 <para>Takes one of the special values
<literal>none
</literal>,
<literal>CS6
</literal>, or
1865 <literal>CS4
</literal>. When
<literal>none
</literal> no IP service type is set to the packet
1866 sent from the DHCPv4 client. When
<literal>CS6
</literal> (network control) or
1867 <literal>CS4
</literal> (realtime), the corresponding service type will be set. Defaults to
1868 <literal>CS6
</literal>.
</para>
1872 <!-- How to use the DHCP lease -->
1875 <term><varname>Label=
</varname></term>
1877 <para>Specifies the label for the IPv4 address received from the DHCP server. The label must
1878 be a
7-bit ASCII string with a length of
1…
15 characters. Defaults to unset.
</para>
1883 <term><varname>UseDNS=
</varname></term>
1885 <para>When true (the default), the DNS servers received from the DHCP server will be used.
1888 <para>This corresponds to the
<option>nameserver
</option> option in
1889 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1895 <term><varname>RoutesToDNS=
</varname></term>
1897 <para>When true, the routes to the DNS servers received from the DHCP server will be
1898 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored. Defaults to
1904 <term><varname>UseNTP=
</varname></term>
1906 <para>When true (the default), the NTP servers received from the DHCP server will be used by
1907 <filename>systemd-timesyncd.service
</filename>.
</para>
1912 <term><varname>RoutesToNTP=
</varname></term>
1914 <para>When true, the routes to the NTP servers received from the DHCP server will be
1915 configured. When
<varname>UseNTP=
</varname> is disabled, this setting is ignored. Defaults to
1921 <term><varname>UseSIP=
</varname></term>
1923 <para>When true (the default), the SIP servers received from the DHCP server will be collected
1924 and made available to client programs.
</para>
1929 <term><varname>UseMTU=
</varname></term>
1931 <para>When true, the interface maximum transmission unit from the DHCP server will be used on
1932 the current link. If
<varname>MTUBytes=
</varname> is set, then this setting is ignored.
1933 Defaults to false.
</para>
1935 <para>Note, some drivers will reset the interfaces if the MTU is changed. For such
1936 interfaces, please try to use
<varname>IgnoreCarrierLoss=
</varname> with a short timespan,
1937 e.g.
<literal>3 seconds
</literal>.
</para>
1942 <term><varname>UseHostname=
</varname></term>
1944 <para>When true (the default), the hostname received from the DHCP server will be set as the
1945 transient hostname of the system.
</para>
1950 <term><varname>UseDomains=
</varname></term>
1952 <para>Takes a boolean, or the special value
<option>route
</option>. When true, the domain
1953 name received from the DHCP server will be used as DNS search domain over this link, similar
1954 to the effect of the
<option>Domains=
</option> setting. If set to
<option>route
</option>, the
1955 domain name received from the DHCP server will be used for routing DNS queries only, but not
1956 for searching, similar to the effect of the
<option>Domains=
</option> setting when the
1957 argument is prefixed with
<literal>~
</literal>. Defaults to false.
</para>
1959 <para>It is recommended to enable this option only on trusted networks, as setting this
1960 affects resolution of all hostnames, in particular of single-label names. It is generally
1961 safer to use the supplied domain only as routing domain, rather than as search domain, in
1962 order to not have it affect local resolution of single-label names.
</para>
1964 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
1965 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1971 <term><varname>UseRoutes=
</varname></term>
1973 <para>When true (the default), the static routes will be requested from the DHCP server and
1974 added to the routing table with a metric of
1024, and a scope of
<option>global
</option>,
1975 <option>link
</option> or
<option>host
</option>, depending on the route's destination and
1976 gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the link's
1977 own address, the scope will be set to
<option>host
</option>. Otherwise if the gateway is null
1978 (a direct route), a
<option>link
</option> scope will be used. For anything else, scope
1979 defaults to
<option>global
</option>.
</para>
1984 <term><varname>RouteMetric=
</varname></term>
1986 <para>Set the routing metric for routes specified by the DHCP server (including the prefix
1987 route added for the specified prefix). Takes an unsigned integer in the range
0…
4294967295.
1988 Defaults to
1024.
</para>
1993 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1995 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to
1996 unset). The table can be retrieved using
1997 <command>ip route show table
<replaceable>num
</replaceable></command>.
</para>
1999 <para>When used in combination with
<varname>VRF=
</varname>, the VRF's routing table is
2000 used when this parameter is not specified.
</para>
2005 <term><varname>RouteMTUBytes=
</varname></term>
2007 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further
2013 <term><varname>UseGateway=
</varname></term>
2015 <para>When true, the gateway will be requested from the DHCP server and added to the routing
2016 table with a metric of
1024, and a scope of
<option>link
</option>. When unset, the value
2017 specified with
<varname>UseRoutes=
</varname> is used.
</para>
2022 <term><varname>UseTimezone=
</varname></term>
2023 <listitem><para>When true, the timezone received from the DHCP server will be set as timezone
2024 of the local system. Defaults to false.
</para></listitem>
2028 <term><varname>Use6RD=
</varname></term>
2030 <para>When true, subnets of the received IPv6 prefix are assigned to downstream interfaces
2031 which enables
<varname>DHCPPrefixDelegation=
</varname>. See also
2032 <varname>DHCPPrefixDelegation=
</varname> in the [Network] section, the [DHCPPrefixDelegation]
2033 section, and
<ulink url=
"https://tools.ietf.org/html/rfc5969">RFC
5969</ulink>. Defaults to
2039 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
2041 <para>Allows one to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease
2042 lifetime. Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal>. If
2043 specified, the acquired address never expires. Defaults to unset.
</para>
2047 <!-- How to communicate with the server -->
2050 <term><varname>RequestBroadcast=
</varname></term>
2052 <para>Request the server to use broadcast messages before the IP address has been configured.
2053 This is necessary for devices that cannot receive RAW packets, or that cannot receive packets
2054 at all before an IP address has been configured. On the other hand, this must not be enabled
2055 on networks where broadcasts are filtered out.
</para>
2060 <term><varname>MaxAttempts=
</varname></term>
2062 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
2063 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>. Note that the
2064 time between retries is increased exponentially, up to approximately one per minute, so the
2065 network will not be overloaded even if this number is high. The default is suitable in most
2066 circumstances.
</para>
2071 <term><varname>ListenPort=
</varname></term>
2073 <para>Set the port from which the DHCP client packets originate.
</para>
2078 <term><varname>DenyList=
</varname></term>
2080 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
2081 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are rejected.
2082 Note that if
<varname>AllowList=
</varname> is configured then
<varname>DenyList=
</varname> is
2088 <term><varname>AllowList=
</varname></term>
2090 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
2091 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are accepted.
2097 <term><varname>SendRelease=
</varname></term>
2099 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops. Defaults to
2105 <term><varname>SendDecline=
</varname></term>
2107 <para>A boolean. When true,
<command>systemd-networkd
</command> performs IPv4 Duplicate
2108 Address Detection to the acquired address by the DHCPv4 client. If duplicate is detected,
2109 the DHCPv4 client rejects the address by sending a
<constant>DHCPDECLINE
</constant> packet to
2110 the DHCP server, and tries to obtain an IP address again. See
2111 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>. Defaults to false.
</para>
2118 <title>[DHCPv6] Section Options
</title>
2120 <para>The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the
2121 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
2124 <variablelist class='network-directives'
>
2126 <!-- DHCP packet contents -->
2129 <term><varname>MUDURL=
</varname></term>
2130 <term><varname>IAID=
</varname></term>
2131 <term><varname>DUIDType=
</varname></term>
2132 <term><varname>DUIDRawData=
</varname></term>
2133 <term><varname>RequestOptions=
</varname></term>
2135 <para>As in the [DHCPv4] section.
</para>
2140 <term><varname>SendOption=
</varname></term>
2142 <para>As in the [DHCPv4] section, however because DHCPv6 uses
16-bit fields to store option
2143 numbers, the option number is an integer in the range
1…
65536.
</para>
2148 <term><varname>SendVendorOption=
</varname></term>
2150 <para>Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier,
2151 DHCP option number, data type, and data separated with a colon
2152 (
<literal><replaceable>enterprise identifier
</replaceable>:
<replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2153 Enterprise identifier is an unsigned integer in the range
1…
4294967294. The option number
2154 must be an integer in the range
1…
254. Data type takes one of
<literal>uint8
</literal>,
2155 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
2156 <literal>ipv6address
</literal>, or
<literal>string
</literal>. Special characters in the data
2157 string may be escaped using
2158 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2159 escapes
</ulink>. This setting can be specified multiple times. If an empty string is
2160 specified, then all options specified earlier are cleared. Defaults to unset.
</para>
2165 <term><varname>UserClass=
</varname></term>
2167 <para>A DHCPv6 client can use User Class option to identify the type or category of user or
2168 applications it represents. The information contained in this option is a string that
2169 represents the user class of which the client is a member. Each class sets an identifying
2170 string of information to be used by the DHCP service to classify clients. Special characters
2171 in the data string may be escaped using
2172 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2173 escapes
</ulink>. This setting can be specified multiple times. If an empty string is
2174 specified, then all options specified earlier are cleared. Takes a whitespace-separated list
2175 of strings. Note that currently
<constant>NUL
</constant> bytes are not allowed.
</para>
2180 <term><varname>VendorClass=
</varname></term>
2182 <para>A DHCPv6 client can use VendorClass option to identify the vendor that manufactured the
2183 hardware on which the client is running. The information contained in the data area of this
2184 option is contained in one or more opaque fields that identify details of the hardware
2185 configuration. Takes a whitespace-separated list of strings.
</para>
2190 <term><varname>PrefixDelegationHint=
</varname></term>
2192 <para>Takes an IPv6 address with prefix length in the same format as the
2193 <varname>Address=
</varname> in the [Network] section. The DHCPv6 client will include a prefix
2194 hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range
2195 1…
128. Defaults to unset.
</para>
2199 <!-- How to use the DHCP lease -->
2202 <term><varname>UseAddress=
</varname></term>
2204 <para>When true (the default), the IP addresses provided by the DHCPv6 server will be
2210 <term><varname>UseDelegatedPrefix=
</varname></term>
2212 <para>When true (the default), the client will request the DHCPv6 server to delegate
2213 prefixes. If the server provides prefixes to be delegated, then subnets of the prefixes are
2214 assigned to the interfaces which enables
<varname>DHCPPrefixDelegation=
</varname>.
2215 See also the
<varname>DHCPPrefixDelegation=
</varname> setting in the [Network] section,
2216 settings in the [DHCPPrefixDelegation] section, and
2217 <ulink url=
"https://www.rfc-editor.org/rfc/rfc8415.html#section-6.3">RFC
8415</ulink>.
2223 <term><varname>UseDNS=
</varname></term>
2224 <term><varname>UseNTP=
</varname></term>
2225 <term><varname>UseHostname=
</varname></term>
2226 <term><varname>UseDomains=
</varname></term>
2228 <para>As in the [DHCPv4] section.
</para>
2232 <!-- How to communicate with the server -->
2235 <term><varname>WithoutRA=
</varname></term>
2237 <para>Allows DHCPv6 client to start without router advertisements's managed or other
2238 address configuration flag. Takes one of
<literal>no
</literal>,
<literal>solicit
</literal>
2239 or
<literal>information-request
</literal>. If this is not specified,
2240 <literal>solicit
</literal> is used when
<varname>DHCPPrefixDelegation=
</varname> is enabled
2241 and
<varname>UplinkInterface=:self
</varname> is specified in the [DHCPPrefixDelegation]
2242 section. Otherwise, defaults to
<literal>no
</literal>, and the DHCPv6 client will be started
2243 when an RA is received. See also the
<varname>DHCPv6Client=
</varname> setting in the
2244 [IPv6AcceptRA] section.
</para>
2251 <title>[DHCPPrefixDelegation] Section Options
</title>
2252 <para>The [DHCPPrefixDelegation] section configures subnet prefixes of the delegated prefixes
2253 acquired by a DHCPv6 client, or by a DHCPv4 client through the
6RD option on another interface.
2254 The settings in this section are used only when the
<varname>DHCPPrefixDelegation=
</varname>
2255 setting in the [Network] section is enabled.
</para>
2257 <variablelist class='network-directives'
>
2259 <term><varname>UplinkInterface=
</varname></term>
2261 <para>Specifies the name or the index of the uplink interface, or one of the special values
2262 <literal>:self
</literal> and
<literal>:auto
</literal>. When
<literal>:self
</literal>, the
2263 interface itself is considered the uplink interface, and
2264 <varname>WithoutRA=solicit
</varname> is implied if the setting is not explicitly specified.
2265 When
<literal>:auto
</literal>, the first link which acquired prefixes to be delegated from
2266 the DHCPv6 or DHCPv4 server is selected. Defaults to
<literal>:auto
</literal>.
</para>
2271 <term><varname>SubnetId=
</varname></term>
2273 <para>Configure a specific subnet ID on the interface from a (previously) received prefix
2274 delegation. You can either set
"auto" (the default) or a specific subnet ID (as defined in
2275 <ulink url=
"https://tools.ietf.org/html/rfc4291#section-2.5.4">RFC
4291</ulink>, section
2276 2.5.4), in which case the allowed value is hexadecimal, from
0 to
0x7fffffffffffffff
2282 <term><varname>Announce=
</varname></term>
2284 <para>Takes a boolean. When enabled, and
<varname>IPv6SendRA=
</varname> in [Network] section
2285 is enabled, the delegated prefixes are distributed through the IPv6 Router Advertisement.
2286 This setting will be ignored when the
<varname>DHCPPrefixDelegation=
</varname> setting is
2287 enabled on the upstream interface. Defaults to yes.
</para>
2292 <term><varname>Assign=
</varname></term>
2294 <para>Takes a boolean. Specifies whether to add an address from the delegated prefixes which
2295 are received from the WAN interface by the DHCPv6 Prefix Delegation. When true (on LAN
2296 interfce), the EUI-
64 algorithm will be used by default to form an interface identifier from
2297 the delegated prefixes. See also
<varname>Token=
</varname> setting below. Defaults to yes.
2303 <term><varname>Token=
</varname></term>
2305 <para>Specifies an optional address generation mode for assigning an address in each
2306 delegated prefix. This accepts the same syntax as
<varname>Token=
</varname> in the
2307 [IPv6AcceptRA] section. If
<varname>Assign=
</varname> is set to false, then this setting will
2308 be ignored. Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2313 <term><varname>ManageTemporaryAddress=
</varname></term>
2315 <para>As in the [Address] section, but defaults to true.
</para>
2320 <term><varname>RouteMetric=
</varname></term>
2322 <para>The metric of the route to the delegated prefix subnet. Takes an unsigned integer in
2323 the range
0…
4294967295. When set to
0, the kernel's default value is used. Defaults to
256.
2331 <title>[IPv6AcceptRA] Section Options
</title>
2332 <para>The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled
2333 with the
<varname>IPv6AcceptRA=
</varname> setting described above:
</para>
2335 <variablelist class='network-directives'
>
2337 <term><varname>Token=
</varname></term>
2339 <para>Specifies an optional address generation mode for the Stateless Address
2340 Autoconfiguration (SLAAC). The following values are supported:
</para>
2344 <term><option>eui64
</option></term>
2347 The EUI-
64 algorithm will be used to generate an address for that prefix. Only
2348 supported by Ethernet or InfiniBand interfaces.
2353 <term><option>static:
<replaceable>ADDRESS
</replaceable></option></term>
2356 An IPv6 address must be specified after a colon (
<literal>:
</literal>), and the
2357 lower bits of the supplied address are combined with the upper bits of a prefix
2358 received in a Router Advertisement (RA) message to form a complete address. Note
2359 that if multiple prefixes are received in an RA message, or in multiple RA messages,
2360 addresses will be formed from each of them using the supplied address. This mode
2361 implements SLAAC but uses a static interface identifier instead of an identifier
2362 generated by using the EUI-
64 algorithm. Because the interface identifier is static,
2363 if Duplicate Address Detection detects that the computed address is a duplicate
2364 (in use by another node on the link), then this mode will fail to provide an address
2365 for that prefix. If an IPv6 address without mode is specified, then
2366 <literal>static
</literal> mode is assumed.
2371 <term><option>prefixstable[:
<replaceable>ADDRESS
</replaceable>][,
<replaceable>UUID
</replaceable>]
</option></term>
2374 The algorithm specified in
2375 <ulink url=
"https://tools.ietf.org/html/rfc7217">RFC
7217</ulink> will be used to
2376 generate interface identifiers. This mode can optionally take an IPv6 address
2377 separated with a colon (
<literal>:
</literal>). If an IPv6 address is specified,
2378 then an interface identifier is generated only when a prefix received in an RA
2379 message matches the supplied address.
2382 This mode can also optionally take a non-null UUID in the format which
2383 <function>sd_id128_from_string()
</function> accepts, e.g.
2384 <literal>86b123b969ba4b7eb8b3d8605123525a
</literal> or
2385 <literal>86b123b9-
69ba-
4b7e-b8b3-d8605123525a
</literal>. If a UUID is specified, the
2386 value is used as the secret key to generate interface identifiers. If not specified,
2387 then an application specific ID generated with the system's machine-ID will be used
2388 as the secret key. See
2389 <citerefentry><refentrytitle>sd-id128
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2390 <citerefentry><refentrytitle>sd_id128_from_string
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2392 <citerefentry><refentrytitle>sd_id128_get_machine
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2395 Note that the
<literal>prefixstable
</literal> algorithm uses both the interface
2396 name and MAC address as input to the hash to compute the interface identifier, so
2397 if either of those are changed the resulting interface identifier (and address)
2398 will be changed, even if the prefix received in the RA message has not been
2405 <para>If no address generation mode is specified (which is the default), or a received
2406 prefix does not match any of the addresses provided in
<literal>prefixstable
</literal>
2407 mode, then the EUI-
64 algorithm will be used for Ethernet or InfiniBand interfaces,
2408 otherwise
<literal>prefixstable
</literal> will be used to form an interface identifier for
2411 <para>This setting can be specified multiple times. If an empty string is assigned, then
2412 the all previous assignments are cleared.
</para>
2415 <programlisting>Token=eui64
2417 Token=static:::
1a:
2b:
3c:
4d
2419 Token=prefixstable:
2002:da8:
1::
</programlisting></para>
2424 <term><varname>UseDNS=
</varname></term>
2426 <para>When true (the default), the DNS servers received in the Router Advertisement will be used.
</para>
2428 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
2429 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2434 <term><varname>UseDomains=
</varname></term>
2436 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
2437 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
2438 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
2439 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
2440 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
2441 <literal>~
</literal>. Defaults to false.
</para>
2443 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
2444 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
2445 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
2446 single-label names.
</para>
2448 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
2449 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2454 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
2456 <para>The table identifier for the routes received in the Router Advertisement
2457 (a number between
1 and
4294967295, or
0 to unset).
2458 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
2464 <term><varname>RouteMetric=
</varname></term>
2466 <para>Set the routing metric for the routes received in the Router Advertisement. Takes an
2467 unsigned integer in the range
0…
4294967295. Defaults to
1024.
</para>
2472 <term><varname>UseMTU=
</varname></term>
2474 <para>Takes a boolean. When true, the MTU received in the Router Advertisement will be
2475 used. Defaults to true.
</para>
2480 <term><varname>UseGateway=
</varname></term>
2482 <para>When true (the default), the router address will be configured as the default gateway.
2488 <term><varname>UseRoutePrefix=
</varname></term>
2490 <para>When true (the default), the routes corresponding to the route prefixes received in
2491 the Router Advertisement will be configured.
</para>
2496 <term><varname>UseAutonomousPrefix=
</varname></term>
2498 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
2499 precedence over any statically configured ones.
</para>
2504 <term><varname>UseOnLinkPrefix=
</varname></term>
2506 <para>When true (the default), the onlink prefix received in the Router Advertisement will be
2507 used and takes precedence over any statically configured ones.
</para>
2512 <term><varname>RouterDenyList=
</varname></term>
2514 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2515 take a prefix length after
<literal>/
</literal>. Any information advertised by the listed
2516 router is ignored.
</para>
2521 <term><varname>RouterAllowList=
</varname></term>
2523 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2524 take a prefix length after
<literal>/
</literal>. Only information advertised by the listed
2525 router is accepted. Note that if
<varname>RouterAllowList=
</varname> is configured then
2526 <varname>RouterDenyList=
</varname> is ignored.
</para>
2531 <term><varname>PrefixDenyList=
</varname></term>
2533 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2534 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2535 in the list are ignored.
</para>
2540 <term><varname>PrefixAllowList=
</varname></term>
2542 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2543 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2544 in the list are allowed. Note that if
<varname>PrefixAllowList=
</varname> is configured
2545 then
<varname>PrefixDenyList=
</varname> is ignored.
</para>
2550 <term><varname>RouteDenyList=
</varname></term>
2552 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2553 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2554 advertisements in the list are ignored.
</para>
2559 <term><varname>RouteAllowList=
</varname></term>
2561 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2562 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2563 advertisements in the list are allowed. Note that if
<varname>RouteAllowList=
</varname> is
2564 configured then
<varname>RouteDenyList=
</varname> is ignored.
</para>
2569 <term><varname>DHCPv6Client=
</varname></term>
2571 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true, the
2572 DHCPv6 client will be started when the RA has the managed or other information flag. If set
2573 to
<literal>always
</literal>, the DHCPv6 client will be started in managed mode when an RA
2574 is received, even if neither managed nor other information flag is set in the RA. This will
2575 be ignored when
<varname>WithoutRA=
</varname> in the [DHCPv6] section is enabled, or
2576 <varname>UplinkInterface=:self
</varname> in the [DHCPPrefixDelegation] section is
2577 specified. Defaults to true.
</para>
2584 <title>[DHCPServer] Section Options
</title>
2585 <para>The [DHCPServer] section contains settings for the DHCP server, if enabled via the
2586 <varname>DHCPServer=
</varname> option described above:
</para>
2588 <variablelist class='network-directives'
>
2591 <term><varname>ServerAddress=
</varname></term>
2592 <listitem><para>Specifies server address for the DHCP server. Takes an IPv4 address with prefix
2593 length, for example
<literal>192.168.0.1/
24</literal>. This setting may be useful when the link on
2594 which the DHCP server is running has multiple static addresses. When unset, one of static addresses
2595 in the link will be automatically selected. Defaults to unset.
</para></listitem>
2599 <term><varname>PoolOffset=
</varname></term>
2600 <term><varname>PoolSize=
</varname></term>
2602 <listitem><para>Configures the pool of addresses to hand out. The pool
2603 is a contiguous sequence of IP addresses in the subnet configured for
2604 the server address, which does not include the subnet nor the broadcast
2605 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
2606 from the start of subnet, or zero to use the default value.
2607 <varname>PoolSize=
</varname> takes the number of IP addresses in the
2608 pool or zero to use the default value. By default, the pool starts at
2609 the first address after the subnet address and takes up the rest of
2610 the subnet, excluding the broadcast address. If the pool includes
2611 the server address (the default), this is reserved and not handed
2612 out to clients.
</para></listitem>
2616 <term><varname>DefaultLeaseTimeSec=
</varname></term>
2617 <term><varname>MaxLeaseTimeSec=
</varname></term>
2619 <listitem><para>Control the default and maximum DHCP lease
2620 time to pass to clients. These settings take time values in seconds or
2621 another common time unit, depending on the suffix. The default
2622 lease time is used for clients that did not ask for a specific
2623 lease time. If a client asks for a lease time longer than the
2624 maximum lease time, it is automatically shortened to the
2625 specified time. The default lease time defaults to
1h, the
2626 maximum lease time to
12h. Shorter lease times are beneficial
2627 if the configuration data in DHCP leases changes frequently
2628 and clients shall learn the new settings with shorter
2629 latencies. Longer lease times reduce the generated DHCP
2630 network traffic.
</para></listitem>
2634 <term><varname>UplinkInterface=
</varname></term>
2635 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2636 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS, NTP, or SIP
2637 servers is enabled but no servers are specified, the servers configured in the uplink interface
2638 will be emitted. When
<literal>:auto
</literal>, the link which has a default gateway with the
2639 highest priority will be automatically selected. When
<literal>:none
</literal>, no uplink
2640 interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2644 <term><varname>EmitDNS=
</varname></term>
2645 <term><varname>DNS=
</varname></term>
2647 <listitem><para><varname>EmitDNS=
</varname> takes a boolean. Configures whether the DHCP leases
2648 handed out to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>. The
2649 DNS servers to pass to clients may be configured with the
<varname>DNS=
</varname> option, which takes
2650 a list of IPv4 addresses. If the
<varname>EmitDNS=
</varname> option is enabled but no servers
2651 configured, the servers are automatically propagated from an
"uplink" interface that has appropriate
2652 servers set. The
"uplink" interface is determined by the default route of the system with the highest
2653 priority. Note that this information is acquired at the time the lease is handed out, and does not
2654 take uplink interfaces into account that acquire DNS server information at a later point. If no
2655 suitable uplink interface is found the DNS server data from
<filename>/etc/resolv.conf
</filename> is
2656 used. Also, note that the leases are not refreshed if the uplink network configuration changes. To
2657 ensure clients regularly acquire the most current uplink DNS server information, it is thus advisable
2658 to shorten the DHCP lease time via
<varname>MaxLeaseTimeSec=
</varname> described
2659 above.
</para></listitem>
2663 <term><varname>EmitNTP=
</varname></term>
2664 <term><varname>NTP=
</varname></term>
2665 <term><varname>EmitSIP=
</varname></term>
2666 <term><varname>SIP=
</varname></term>
2667 <term><varname>EmitPOP3=
</varname></term>
2668 <term><varname>POP3=
</varname></term>
2669 <term><varname>EmitSMTP=
</varname></term>
2670 <term><varname>SMTP=
</varname></term>
2671 <term><varname>EmitLPR=
</varname></term>
2672 <term><varname>LPR=
</varname></term>
2674 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname> settings
2675 described above, these settings configure whether and what server information for the indicate
2676 protocol shall be emitted as part of the DHCP lease. The same syntax, propagation semantics and
2677 defaults apply as for
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname>.
</para></listitem>
2681 <term><varname>EmitRouter=
</varname></term>
2682 <term><varname>Router=
</varname></term>
2684 <listitem><para>The
<varname>EmitRouter=
</varname> setting takes a boolean value, and configures
2685 whether the DHCP lease should contain the router option. The
<varname>Router=
</varname> setting
2686 takes an IPv4 address, and configures the router address to be emitted. When the
2687 <varname>Router=
</varname> setting is not specified, then the server address will be used for
2688 the router option. When the
<varname>EmitRouter=
</varname> setting is disabled, the
2689 <varname>Router=
</varname> setting will be ignored. The
<varname>EmitRouter=
</varname> setting
2690 defaults to true, and the
<varname>Router=
</varname> setting defaults to unset.
2695 <term><varname>EmitTimezone=
</varname></term>
2696 <term><varname>Timezone=
</varname></term>
2698 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2699 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2700 <varname>Timezone=
</varname> setting takes a timezone string
2701 (such as
<literal>Europe/Berlin
</literal> or
2702 <literal>UTC
</literal>) to pass to clients. If no explicit
2703 timezone is set, the system timezone of the local host is
2704 propagated, as determined by the
2705 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2709 <term><varname>SendOption=
</varname></term>
2711 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2712 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2713 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2714 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2715 <literal>string
</literal>. Special characters in the data string may be escaped using
2716 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2717 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2718 then all options specified earlier are cleared. Defaults to unset.
</para>
2723 <term><varname>SendVendorOption=
</varname></term>
2725 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2726 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2727 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2728 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2729 <literal>string
</literal>. Special characters in the data string may be escaped using
2730 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2731 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2732 then all options specified earlier are cleared. Defaults to unset.
</para>
2736 <term><varname>BindToInterface=
</varname></term>
2738 <para>Takes a boolean value. When
<literal>yes
</literal>, DHCP server socket will be bound
2739 to its network interface and all socket communication will be restricted to this interface.
2740 Defaults to
<literal>yes
</literal>, except if
<varname>RelayTarget=
</varname> is used (see below),
2741 in which case it defaults to
<literal>no
</literal>.
</para>
2745 <term><varname>RelayTarget=
</varname></term>
2747 <para>Takes an IPv4 address, which must be in the format described in
2748 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
2749 Turns this DHCP server into a DHCP relay agent. See
<ulink url=
"https://tools.ietf.org/html/rfc1542">RFC
1542</ulink>.
2750 The address is the address of DHCP server or another relay agent to forward DHCP messages to and from.
</para>
2754 <term><varname>RelayAgentCircuitId=
</varname></term>
2756 <para>Specifies value for Agent Circuit ID suboption of Relay Agent Information option.
2757 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2758 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2759 Defaults to unset (means no Agent Circuit ID suboption is generated).
2760 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2764 <term><varname>RelayAgentRemoteId=
</varname></term>
2766 <para>Specifies value for Agent Remote ID suboption of Relay Agent Information option.
2767 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2768 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2769 Defaults to unset (means no Agent Remote ID suboption is generated).
2770 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2778 <title>[DHCPServerStaticLease] Section Options
</title>
2779 <para>The
<literal>[DHCPServerStaticLease]
</literal> section configures a static DHCP lease to assign a
2780 fixed IPv4 address to a specific device based on its MAC address. This section can be specified multiple
2783 <variablelist class='network-directives'
>
2785 <term><varname>MACAddress=
</varname></term>
2787 <listitem><para>The hardware address of a device to match. This key is mandatory.
</para></listitem>
2791 <term><varname>Address=
</varname></term>
2793 <listitem><para>The IPv4 address that should be assigned to the device that was matched with
2794 <varname>MACAddress=
</varname>. This key is mandatory.
</para></listitem>
2800 <title>[IPv6SendRA] Section Options
</title>
2801 <para>The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether
2802 to act as a router, if enabled via the
<varname>IPv6SendRA=
</varname> option described above. IPv6
2803 network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections.
2806 <variablelist class='network-directives'
>
2809 <term><varname>Managed=
</varname></term>
2810 <term><varname>OtherInformation=
</varname></term>
2812 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2813 addresses on the network link when
<varname>Managed=
</varname>
2814 is set to
<literal>true
</literal> or if only additional network
2815 information can be obtained via DHCPv6 for the network link when
2816 <varname>OtherInformation=
</varname> is set to
2817 <literal>true
</literal>. Both settings default to
2818 <literal>false
</literal>, which means that a DHCPv6 server is not being
2819 used.
</para></listitem>
2823 <term><varname>RouterLifetimeSec=
</varname></term>
2825 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. The value must be
0
2826 seconds, or between
4 seconds and
9000 seconds. When set to
0, the host is not acting as a router.
2827 Defaults to
1800 seconds (
30 minutes).
</para>
2832 <term><varname>RouterPreference=
</varname></term>
2834 <listitem><para>Configures IPv6 router preference if
2835 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2836 <literal>high
</literal>,
<literal>medium
</literal> and
2837 <literal>low
</literal>, with
<literal>normal
</literal> and
2838 <literal>default
</literal> added as synonyms for
2839 <literal>medium
</literal> just to make configuration easier. See
2840 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2841 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2845 <term><varname>UplinkInterface=
</varname></term>
2846 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2847 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS servers or
2848 search domains is enabled but no servers are specified, the servers configured in the uplink
2849 interface will be emitted. When
<literal>:auto
</literal>, the value specified to the same
2850 setting in the [DHCPPrefixDelegation] section will be used if
2851 <varname>DHCPPrefixDelegation=
</varname> is enabled, otherwise the link which has a default
2852 gateway with the highest priority will be automatically selected. When
<literal>:none
</literal>,
2853 no uplink interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2857 <term><varname>EmitDNS=
</varname></term>
2858 <term><varname>DNS=
</varname></term>
2860 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses
2861 that are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is true.
2862 <varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that case
2863 the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS servers are
2864 read from the [Network] section. If the [Network] section does not contain any DNS servers
2865 either, DNS servers from the uplink interface specified in
<varname>UplinkInterface=
</varname>
2866 will be used. When
<varname>EmitDNS=
</varname> is false, no DNS server information is sent in
2867 Router Advertisement messages.
<varname>EmitDNS=
</varname> defaults to true.
</para></listitem>
2871 <term><varname>EmitDomains=
</varname></term>
2872 <term><varname>Domains=
</varname></term>
2874 <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when
2875 <varname>EmitDomains=
</varname> is true. If
<varname>Domains=
</varname> is empty, DNS search
2876 domains are read from the [Network] section. If the [Network] section does not contain any DNS
2877 search domains either, DNS search domains from the uplink interface specified in
2878 <varname>UplinkInterface=
</varname> will be used. When
<varname>EmitDomains=
</varname> is false,
2879 no DNS search domain information is sent in Router Advertisement messages.
2880 <varname>EmitDomains=
</varname> defaults to true.
</para></listitem>
2884 <term><varname>DNSLifetimeSec=
</varname></term>
2886 <listitem><para>Lifetime in seconds for the DNS server addresses listed in
2887 <varname>DNS=
</varname> and search domains listed in
<varname>Domains=
</varname>. Defaults to
2888 3600 seconds (one hour).
</para></listitem>
2895 <title>[IPv6Prefix] Section Options
</title>
2896 <para>One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router
2897 Advertisements. See
<ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink> for further
2900 <variablelist class='network-directives'
>
2903 <term><varname>AddressAutoconfiguration=
</varname></term>
2904 <term><varname>OnLink=
</varname></term>
2906 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2907 autoconfigured with this prefix and whether the prefix can be used for
2908 onlink determination. Both settings default to
<literal>true
</literal>
2909 in order to ease configuration.
2914 <term><varname>Prefix=
</varname></term>
2916 <listitem><para>The IPv6 prefix that is to be distributed to hosts. Similarly to configuring static
2917 IPv6 addresses, the setting is configured as an IPv6 prefix and its prefix length, separated by a
2918 <literal>/
</literal> character. Use multiple [IPv6Prefix] sections to configure multiple IPv6
2919 prefixes since prefix lifetimes, address autoconfiguration and onlink status may differ from one
2920 prefix to another.
</para></listitem>
2924 <term><varname>PreferredLifetimeSec=
</varname></term>
2925 <term><varname>ValidLifetimeSec=
</varname></term>
2927 <listitem><para>Preferred and valid lifetimes for the prefix measured in seconds.
2928 <varname>PreferredLifetimeSec=
</varname> defaults to
1800 seconds (
30 minutes) and
2929 <varname>ValidLifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2933 <term><varname>Assign=
</varname></term>
2934 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2939 <term><varname>Token=
</varname></term>
2941 <para>Specifies an optional address generation mode for assigning an address in each
2942 prefix. This accepts the same syntax as
<varname>Token=
</varname> in the [IPv6AcceptRA]
2943 section. If
<varname>Assign=
</varname> is set to false, then this setting will be ignored.
2944 Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2949 <term><varname>RouteMetric=
</varname></term>
2951 <para>The metric of the prefix route. Takes an unsigned integer in the range
0…
4294967295.
2952 When unset or set to
0, the kernel's default value is used. This setting is ignored when
2953 <varname>Assign=
</varname> is false.
</para>
2960 <title>[IPv6RoutePrefix] Section Options
</title>
2961 <para>One or more [IPv6RoutePrefix] sections contain the IPv6
2962 prefix routes that are announced via Router Advertisements. See
2963 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2964 for further details.
</para>
2966 <variablelist class='network-directives'
>
2969 <term><varname>Route=
</varname></term>
2971 <listitem><para>The IPv6 route that is to be distributed to hosts. Similarly to configuring static
2972 IPv6 routes, the setting is configured as an IPv6 prefix routes and its prefix route length,
2973 separated by a
<literal>/
</literal> character. Use multiple [IPv6PrefixRoutes] sections to configure
2974 multiple IPv6 prefix routes.
</para></listitem>
2978 <term><varname>LifetimeSec=
</varname></term>
2980 <listitem><para>Lifetime for the route prefix measured in seconds.
2981 <varname>LifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2988 <title>[Bridge] Section Options
</title>
2989 <para>The [Bridge] section accepts the following keys:
</para>
2990 <variablelist class='network-directives'
>
2992 <term><varname>UnicastFlood=
</varname></term>
2994 <para>Takes a boolean. Controls whether the bridge should flood
2995 traffic for which an FDB entry is missing and the destination
2996 is unknown through this port. When unset, the kernel's default will be used.
3001 <term><varname>MulticastFlood=
</varname></term>
3003 <para>Takes a boolean. Controls whether the bridge should flood
3004 traffic for which an MDB entry is missing and the destination
3005 is unknown through this port. When unset, the kernel's default will be used.
3010 <term><varname>MulticastToUnicast=
</varname></term>
3012 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
3013 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
3014 When unset, the kernel's default will be used.
3019 <term><varname>NeighborSuppression=
</varname></term>
3021 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
3022 this port. When unset, the kernel's default will be used.
3027 <term><varname>Learning=
</varname></term>
3029 <para>Takes a boolean. Configures whether MAC address learning is enabled for
3030 this port. When unset, the kernel's default will be used.
3035 <term><varname>HairPin=
</varname></term>
3037 <para>Takes a boolean. Configures whether traffic may be sent back out of the port on which it
3038 was received. When this flag is false, then the bridge will not forward traffic back out of the
3039 receiving port. When unset, the kernel's default will be used.
</para>
3043 <term><varname>UseBPDU=
</varname></term>
3045 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
3046 processed by the bridge port. When unset, the kernel's default will be used.
</para>
3050 <term><varname>FastLeave=
</varname></term>
3052 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
3053 traffic on a port that receives an IGMP Leave message. It is only used with
3054 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
3058 <term><varname>AllowPortToBeRoot=
</varname></term>
3060 <para>Takes a boolean. Configures whether a given port is allowed to
3061 become a root port. Only used when STP is enabled on the bridge.
3062 When unset, the kernel's default will be used.
</para>
3066 <term><varname>ProxyARP=
</varname></term>
3068 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
3069 When unset, the kernel's default will be used.
</para>
3073 <term><varname>ProxyARPWiFi=
</varname></term>
3075 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
3076 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
3077 When unset, the kernel's default will be used.
</para>
3081 <term><varname>MulticastRouter=
</varname></term>
3083 <para>Configures this port for having multicast routers attached. A port with a multicast
3084 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
3085 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
3086 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
3087 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
3088 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
3092 <term><varname>Cost=
</varname></term>
3094 <para>Sets the
"cost" of sending packets of this interface.
3095 Each port in a bridge may have a different speed and the cost
3096 is used to decide which link to use. Faster interfaces
3097 should have lower costs. It is an integer value between
1 and
3102 <term><varname>Priority=
</varname></term>
3104 <para>Sets the
"priority" of sending packets on this interface.
3105 Each port in a bridge may have a different priority which is used
3106 to decide which link to use. Lower value means higher priority.
3107 It is an integer value between
0 to
63. Networkd does not set any
3108 default, meaning the kernel default value of
32 is used.
</para>
3114 <title>[BridgeFDB] Section Options
</title>
3115 <para>The [BridgeFDB] section manages the forwarding database table of a port and accepts the following
3116 keys. Specify several [BridgeFDB] sections to configure several static MAC table entries.
</para>
3118 <variablelist class='network-directives'
>
3120 <term><varname>MACAddress=
</varname></term>
3122 <para>As in the [Network] section. This key is mandatory.
</para>
3126 <term><varname>Destination=
</varname></term>
3128 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
3132 <term><varname>VLANId=
</varname></term>
3134 <para>The VLAN ID for the new static MAC table entry. If
3135 omitted, no VLAN ID information is appended to the new static MAC
3140 <term><varname>VNI=
</varname></term>
3142 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
3143 the remote VXLAN tunnel endpoint. Takes a number in the range
1…
16777215.
3144 Defaults to unset.
</para>
3148 <term><varname>AssociatedWith=
</varname></term>
3150 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
3151 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
3152 <literal>use
</literal> means the address is in use. User space can use this option to
3153 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
3154 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
3155 means the address is associated with master devices fdb.
<literal>router
</literal> means
3156 the destination address is associated with a router. Note that it's valid if the referenced
3157 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
3161 <term><varname>OutgoingInterface=
</varname></term>
3163 <para>Specifies the name or index of the outgoing interface for the VXLAN device driver to
3164 reach the remote VXLAN tunnel endpoint. Defaults to unset.
</para>
3170 <title>[BridgeMDB] Section Options
</title>
3171 <para>The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following
3172 keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.
</para>
3174 <variablelist class='network-directives'
>
3176 <term><varname>MulticastGroupAddress=
</varname></term>
3178 <para>Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.
</para>
3182 <term><varname>VLANId=
</varname></term>
3184 <para>The VLAN ID for the new entry. Valid ranges are
0 (no VLAN) to
4094. Optional, defaults to
0.
</para>
3191 <title>[LLDP] Section Options
</title>
3192 <para>The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following
3194 <variablelist class='network-directives'
>
3196 <term><varname>MUDURL=
</varname></term>
3198 <para>When configured, the specified Manufacturer Usage Descriptions (MUD) URL will be sent in
3199 LLDP packets. The syntax and semantics are the same as for
<varname>MUDURL=
</varname> in the
3200 [DHCPv4] section described above.
</para>
3202 <para>The MUD URLs received via LLDP packets are saved and can be read using the
3203 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
3210 <title>[CAN] Section Options
</title>
3211 <para>The [CAN] section manages the Controller Area Network (CAN bus) and accepts the
3212 following keys:
</para>
3213 <variablelist class='network-directives'
>
3215 <term><varname>BitRate=
</varname></term>
3217 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
3218 be used here. Takes a number in the range
1…
4294967295.
</para>
3222 <term><varname>SamplePoint=
</varname></term>
3224 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
3225 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>). This will be ignored when
3226 <varname>BitRate=
</varname> is unspecified.
</para>
3230 <term><varname>TimeQuantaNSec=
</varname></term>
3231 <term><varname>PropagationSegment=
</varname></term>
3232 <term><varname>PhaseBufferSegment1=
</varname></term>
3233 <term><varname>PhaseBufferSegment2=
</varname></term>
3234 <term><varname>SyncJumpWidth=
</varname></term>
3236 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3237 synchronization jump width, which allow one to define the CAN bit-timing in a hardware
3238 independent format as proposed by the Bosch CAN
2.0 Specification.
3239 <varname>TimeQuantaNSec=
</varname> takes a timespan in nanoseconds.
3240 <varname>PropagationSegment=
</varname>,
<varname>PhaseBufferSegment1=
</varname>,
3241 <varname>PhaseBufferSegment2=
</varname>, and
<varname>SyncJumpWidth=
</varname> take number
3242 of time quantum specified in
<varname>TimeQuantaNSec=
</varname> and must be an unsigned
3243 integer in the range
0…
4294967295. These settings except for
3244 <varname>SyncJumpWidth=
</varname> will be ignored when
<varname>BitRate=
</varname> is
3249 <term><varname>DataBitRate=
</varname></term>
3250 <term><varname>DataSamplePoint=
</varname></term>
3252 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
3253 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
3257 <term><varname>DataTimeQuantaNSec=
</varname></term>
3258 <term><varname>DataPropagationSegment=
</varname></term>
3259 <term><varname>DataPhaseBufferSegment1=
</varname></term>
3260 <term><varname>DataPhaseBufferSegment2=
</varname></term>
3261 <term><varname>DataSyncJumpWidth=
</varname></term>
3263 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3264 synchronization jump width for the data phase, if CAN-FD is used. These settings are
3265 analogous to the
<varname>TimeQuantaNSec=
</varname> or related settings.
</para>
3269 <term><varname>FDMode=
</varname></term>
3271 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
3272 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
3273 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys, or
3274 <varname>DataTimeQuanta=
</varname> and related settings.
</para>
3278 <term><varname>FDNonISO=
</varname></term>
3280 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
3281 interface. When unset, the kernel's default will be used.
</para>
3285 <term><varname>RestartSec=
</varname></term>
3287 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
3288 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
3289 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
3290 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
3291 automatic restart off. By default automatic restart is disabled.
</para>
3295 <term><varname>Termination=
</varname></term>
3297 <para>Takes a boolean or a termination resistor value in ohm in the range
0…
65535. When
3298 <literal>yes
</literal>, the termination resistor is set to
120 ohm. When
3299 <literal>no
</literal> or
<literal>0</literal> is set, the termination resistor is disabled.
3300 When unset, the kernel's default will be used.
</para>
3304 <term><varname>TripleSampling=
</varname></term>
3306 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
3307 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
3311 <term><varname>BusErrorReporting=
</varname></term>
3313 <para>Takes a boolean. When
<literal>yes
</literal>, reporting of CAN bus errors is activated
3314 (those include single bit, frame format, and bit stuffing errors, unable to send dominant bit,
3315 unable to send recessive bit, bus overload, active error announcement, error occurred on
3316 transmission). When unset, the kernel's default will be used. Note: in case of a CAN bus with a
3317 single CAN device, sending a CAN frame may result in a huge number of CAN bus errors.
</para>
3321 <term><varname>ListenOnly=
</varname></term>
3323 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
3324 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
3325 bit. Listen-only mode is important to debug CAN networks without interfering with the
3326 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
3331 <term><varname>Loopback=
</varname></term>
3333 <para>Takes a boolean. When
<literal>yes
</literal>, loopback mode is enabled. When the
3334 loopback mode is enabled, the interface treats messages transmitted by itself as received
3335 messages. The loopback mode is important to debug CAN networks. When unset, the kernel's
3336 default will be used.
</para>
3340 <term><varname>OneShot=
</varname></term>
3342 <para>Takes a boolean. When
<literal>yes
</literal>, one-shot mode is enabled. When unset,
3343 the kernel's default will be used.
</para>
3347 <term><varname>PresumeAck=
</varname></term>
3349 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will ignore missing CAN
3350 ACKs. When unset, the kernel's default will be used.
</para>
3354 <term><varname>ClassicDataLengthCode=
</varname></term>
3356 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will handle the
4bit data
3357 length code (DLC). When unset, the kernel's default will be used.
</para>
3364 <title>[IPoIB] Section Options
</title>
3365 <para>The [IPoIB] section manages the IP over Infiniband and accepts the following keys:
</para>
3366 <variablelist class='network-directives'
>
3367 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_mode" />
3368 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_umcast" />
3373 <title>[QDisc] Section Options
</title>
3374 <para>The [QDisc] section manages the traffic control queueing discipline (qdisc).
</para>
3376 <variablelist class='network-directives'
>
3378 <term><varname>Parent=
</varname></term>
3380 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
3381 or
<literal>ingress
</literal>. This is mandatory.
</para>
3385 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3390 <title>[NetworkEmulator] Section Options
</title>
3391 <para>The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It
3392 can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP
3393 applications, or limit the bandwidth usage of a particular service to simulate internet connections.
3396 <variablelist class='network-directives'
>
3397 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3398 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3401 <term><varname>DelaySec=
</varname></term>
3403 <para>Specifies the fixed amount of delay to be added to all packets going out of the
3404 interface. Defaults to unset.
</para>
3409 <term><varname>DelayJitterSec=
</varname></term>
3411 <para>Specifies the chosen delay to be added to the packets outgoing to the network
3412 interface. Defaults to unset.
</para>
3417 <term><varname>PacketLimit=
</varname></term>
3419 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
3420 An unsigned integer in the range
0…
4294967294. Defaults to
1000.
</para>
3425 <term><varname>LossRate=
</varname></term>
3427 <para>Specifies an independent loss probability to be added to the packets outgoing from the
3428 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3433 <term><varname>DuplicateRate=
</varname></term>
3435 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
3436 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3443 <title>[TokenBucketFilter] Section Options
</title>
3444 <para>The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter
3447 <variablelist class='network-directives'
>
3448 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3449 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3452 <term><varname>LatencySec=
</varname></term>
3454 <para>Specifies the latency parameter, which specifies the maximum amount of time a
3455 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
3460 <term><varname>LimitBytes=
</varname></term>
3462 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
3463 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
3464 respectively, to the base of
1024. Defaults to unset.
</para>
3469 <term><varname>BurstBytes=
</varname></term>
3471 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
3472 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
3473 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to
3479 <term><varname>Rate=
</varname></term>
3481 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
3482 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
3483 Defaults to unset.
</para>
3488 <term><varname>MPUBytes=
</varname></term>
3490 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
3491 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3492 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to zero.
</para>
3497 <term><varname>PeakRate=
</varname></term>
3499 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
3500 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3501 1000. Defaults to unset.
</para>
3506 <term><varname>MTUBytes=
</varname></term>
3508 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
3509 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
3510 Defaults to unset.
</para>
3517 <title>[PIE] Section Options
</title>
3518 <para>The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral
3519 controller-Enhanced (PIE).
</para>
3521 <variablelist class='network-directives'
>
3522 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3523 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3526 <term><varname>PacketLimit=
</varname></term>
3528 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3529 incoming packets are dropped. An unsigned integer in the range
1…
4294967294. Defaults to unset and
3530 kernel's default is used.
</para>
3537 <title>[FlowQueuePIE] Section Options
</title>
3538 <para>The
<literal>[FlowQueuePIE]
</literal> section manages the queueing discipline
3539 (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).
</para>
3541 <variablelist class='network-directives'
>
3542 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3543 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3546 <term><varname>PacketLimit=
</varname></term>
3548 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3549 incoming packets are dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and
3550 kernel's default is used.
</para>
3557 <title>[StochasticFairBlue] Section Options
</title>
3558 <para>The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue
3561 <variablelist class='network-directives'
>
3562 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3563 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3566 <term><varname>PacketLimit=
</varname></term>
3568 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3569 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3570 kernel's default is used.
</para>
3577 <title>[StochasticFairnessQueueing] Section Options
</title>
3578 <para>The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic
3579 fairness queueing (sfq).
</para>
3581 <variablelist class='network-directives'
>
3582 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3583 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3586 <term><varname>PerturbPeriodSec=
</varname></term>
3588 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
3595 <title>[BFIFO] Section Options
</title>
3596 <para>The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First
3599 <variablelist class='network-directives'
>
3600 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3601 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3604 <term><varname>LimitBytes=
</varname></term>
3606 <para>Specifies the hard limit in bytes on the FIFO buffer size. The size limit prevents overflow
3607 in case the kernel is unable to dequeue packets as quickly as it receives them. When this limit is
3608 reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed
3609 as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3610 kernel default is used.
</para>
3617 <title>[PFIFO] Section Options
</title>
3618 <para>The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out
3621 <variablelist class='network-directives'
>
3622 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3623 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3626 <term><varname>PacketLimit=
</varname></term>
3628 <para>Specifies the hard limit on the number of packets in the FIFO queue. The size limit prevents
3629 overflow in case the kernel is unable to dequeue packets as quickly as it receives them. When this
3630 limit is reached, incoming packets are dropped. An unsigned integer in the range
3631 0…
4294967294. Defaults to unset and kernel's default is used.
</para>
3638 <title>[PFIFOHeadDrop] Section Options
</title>
3639 <para>The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out
3640 Head Drop (pfifo_head_drop).
</para>
3642 <variablelist class='network-directives'
>
3643 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3644 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3647 <term><varname>PacketLimit=
</varname></term>
3649 <para>As in [PFIFO] section.
</para></listitem>
3655 <title>[PFIFOFast] Section Options
</title>
3656 <para>The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast
3657 (pfifo_fast).
</para>
3659 <variablelist class='network-directives'
>
3660 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3661 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3666 <title>[CAKE] Section Options
</title>
3667 <para>The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced
3670 <variablelist class='network-directives'
>
3671 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3672 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3675 <term><varname>Bandwidth=
</varname></term>
3677 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
3678 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
3679 unset and kernel's default is used.
</para>
3684 <term><varname>AutoRateIngress=
</varname></term>
3686 <para>Takes a boolean value. Enables automatic capacity estimation based on traffic arriving
3687 at this qdisc. This is most likely to be useful with cellular links, which tend to change
3688 quality randomly. If this setting is enabled, the
<varname>Bandwidth=
</varname> setting is
3689 used as an initial estimate. Defaults to unset, and the kernel's default is used.
</para>
3694 <term><varname>OverheadBytes=
</varname></term>
3696 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative.
3697 Takes an integer in the range -
64…
256. Defaults to unset and kernel's default is used.
3703 <term><varname>MPUBytes=
</varname></term>
3705 <para>Rounds each packet (including overhead) up to the specified bytes. Takes an integer in
3706 the range
1…
256. Defaults to unset and kernel's default is used.
</para>
3711 <term><varname>CompensationMode=
</varname></term>
3713 <para>Takes one of
<literal>none
</literal>,
<literal>atm
</literal>, or
<literal>ptm
</literal>.
3714 Specifies the compensation mode for overhead calculation. When
<literal>none
</literal>, no
3715 compensation is taken into account. When
<literal>atm
</literal>, enables the compensation for
3716 ATM cell framing, which is normally found on ADSL links. When
<literal>ptm
</literal>, enables
3717 the compensation for PTM encoding, which is normally found on VDSL2 links and uses a
64b/
65b
3718 encoding scheme. Defaults to unset and the kernel's default is used.
</para>
3723 <term><varname>UseRawPacketSize=
</varname></term>
3725 <para>Takes a boolean value. When true, the packet size reported by the Linux kernel will be
3726 used, instead of the underlying IP packet size. Defaults to unset, and the kernel's default
3732 <term><varname>FlowIsolationMode=
</varname></term>
3734 <para>CAKE places packets from different flows into different queues, then packets from each
3735 queue are delivered fairly. This specifies whether the fairness is based on source address,
3736 destination address, individual flows, or any combination of those. The available values are:
3741 <term><option>none
</option></term>
3743 The flow isolation is disabled, and all traffic passes through a single queue.
3747 <term><option>src-host
</option></term>
3749 Flows are defined only by source address. Equivalnet to the
<literal>srchost
</literal>
3750 option for
<command>tc qdisc
</command> command. See also
3751 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3755 <term><option>dst-host
</option></term>
3757 Flows are defined only by destination address. Equivalnet to the
3758 <literal>srchost
</literal> option for
<command>tc qdisc
</command> command. See also
3759 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3763 <term><option>hosts
</option></term>
3765 Flows are defined by source-destination host pairs. Equivalent to the same option for
3766 <command>tc qdisc
</command> command. See also
3767 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3771 <term><option>flows
</option></term>
3773 Flows are defined by the entire
5-tuple of source address, destination address,
3774 transport protocol, source port and destination port. Equivalent to the same option for
3775 <command>tc qdisc
</command> command. See also
3776 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3780 <term><option>dual-src-host
</option></term>
3782 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3783 fairness is applied first over source addresses, then over individual flows. Equivalnet
3784 to the
<literal>dual-srchost
</literal> option for
<command>tc qdisc
</command> command.
3786 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3790 <term><option>dual-dst-host
</option></term>
3792 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3793 fairness is applied first over destination addresses, then over individual flows.
3794 Equivalnet to the
<literal>dual-dsthost
</literal> option for
3795 <command>tc qdisc
</command> command. See also
3796 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3800 <term><option>triple
</option></term>
3802 Flows are defined by the
5-tuple (see
<literal>flows
</literal>), and fairness is
3803 applied over source and destination addresses, and also over individual flows.
3804 Equivalnet to the
<literal>triple-isolate
</literal> option for
3805 <command>tc qdisc
</command> command. See also
3806 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3811 <para>Defaults to unset and the kernel's default is used.
</para>
3816 <term><varname>NAT=
</varname></term>
3818 <para>Takes a boolean value. When true, CAKE performs a NAT lookup before applying
3819 flow-isolation rules, to determine the true addresses and port numbers of the packet, to
3820 improve fairness between hosts inside the NAT. This has no practical effect when
3821 <varname>FlowIsolationMode=
</varname> is
<literal>none
</literal> or
<literal>flows
</literal>,
3822 or if NAT is performed on a different host. Defaults to unset, and the kernel's default is
3828 <term><varname>PriorityQueueingPreset=
</varname></term>
3830 <para>CAKE divides traffic into
<literal>tins
</literal>, and each tin has its own independent
3831 set of flow-isolation queues, bandwidth threshold, and priority. This specifies the preset of
3832 tin profiles. The available values are:
</para>
3836 <term><option>besteffort
</option></term>
3838 Disables priority queueing by placing all traffic in one tin.
3842 <term><option>precedence
</option></term>
3844 Enables priority queueing based on the legacy interpretation of TOS
3845 <literal>Precedence
</literal> field. Use of this preset on the modern Internet is
3850 <term><option>diffserv8
</option></term>
3852 Enables priority queueing based on the Differentiated Service
3853 (
<literal>DiffServ
</literal>) field with eight tins: Background Traffic, High
3854 Throughput, Best Effort, Video Streaming, Low Latency Transactions, Interactive Shell,
3855 Minimum Latency, and Network Control.
3859 <term><option>diffserv4
</option></term>
3861 Enables priority queueing based on the Differentiated Service
3862 (
<literal>DiffServ
</literal>) field with four tins: Background Traffic, Best Effort,
3863 Streaming Media, and Latency Sensitive.
3867 <term><option>diffserv3
</option></term>
3869 Enables priority queueing based on the Differentiated Service
3870 (
<literal>DiffServ
</literal>) field with three tins: Background Traffic, Best Effort,
3871 and Latency Sensitive.
3876 <para>Defaults to unset, and the kernel's default is used.
</para>
3881 <term><varname>FirewallMark=
</varname></term>
3883 <para>Takes an integer in the range
1…
4294967295. When specified, firewall-mark-based
3884 overriding of CAKE's tin selection is enabled. Defaults to unset, and the kernel's default is
3890 <term><varname>Wash=
</varname></term>
3892 <para>Takes a boolean value. When true, CAKE clears the DSCP fields, except for ECN bits, of
3893 any packet passing through CAKE. Defaults to unset, and the kernel's default is used.
</para>
3898 <term><varname>SplitGSO=
</varname></term>
3900 <para>Takes a boolean value. When true, CAKE will split General Segmentation Offload (GSO)
3901 super-packets into their on-the-wire components and dequeue them individually. Defaults to
3902 unset, and the kernel's default is used.
</para>
3910 <title>[ControlledDelay] Section Options
</title>
3911 <para>The [ControlledDelay] section manages the queueing discipline (qdisc) of
3912 controlled delay (CoDel).
</para>
3914 <variablelist class='network-directives'
>
3915 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3916 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3919 <term><varname>PacketLimit=
</varname></term>
3921 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3922 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3923 kernel's default is used.
</para>
3928 <term><varname>TargetSec=
</varname></term>
3930 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3931 Defaults to unset and kernel's default is used.
</para>
3936 <term><varname>IntervalSec=
</varname></term>
3938 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3939 become too stale. Defaults to unset and kernel's default is used.
</para>
3944 <term><varname>ECN=
</varname></term>
3946 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3947 unset and kernel's default is used.
</para>
3952 <term><varname>CEThresholdSec=
</varname></term>
3954 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3955 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3962 <title>[DeficitRoundRobinScheduler] Section Options
</title>
3963 <para>The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round
3964 Robin Scheduler (DRR).
</para>
3966 <variablelist class='network-directives'
>
3967 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3968 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3973 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
3974 <para>The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round
3975 Robin Scheduler (DRR).
</para>
3977 <variablelist class='network-directives'
>
3978 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3979 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3982 <term><varname>QuantumBytes=
</varname></term>
3984 <para>Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves
3985 to the next class. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3986 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to the MTU of the
3995 <title>[EnhancedTransmissionSelection] Section Options
</title>
3996 <para>The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced
3997 Transmission Selection (ETS).
</para>
3999 <variablelist class='network-directives'
>
4000 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4001 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4004 <term><varname>Bands=
</varname></term>
4006 <para>Specifies the number of bands. An unsigned integer in the range
1…
16. This value has to be at
4007 least large enough to cover the strict bands specified through the
<varname>StrictBands=
</varname>
4008 and bandwidth-sharing bands specified in
<varname>QuantumBytes=
</varname>.
</para>
4013 <term><varname>StrictBands=
</varname></term>
4015 <para>Specifies the number of bands that should be created in strict mode. An unsigned integer in
4016 the range
1…
16.
</para>
4021 <term><varname>QuantumBytes=
</varname></term>
4023 <para>Specifies the white-space separated list of quantum used in band-sharing bands. When
4024 suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4025 respectively, to the base of
1024. This setting can be specified multiple times. If an empty
4026 string is assigned, then the all previous assignments are cleared.
</para>
4031 <term><varname>PriorityMap=
</varname></term>
4033 <para>The priority map maps the priority of a packet to a band. The argument is a whitespace
4034 separated list of numbers. The first number indicates which band the packets with priority
0 should
4035 be put to, the second is for priority
1, and so on. There can be up to
16 numbers in the list. If
4036 there are fewer, the default band that traffic with one of the unmentioned priorities goes to is
4037 the last one. Each band number must be in the range
0…
255. This setting can be specified multiple
4038 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
4045 <title>[GenericRandomEarlyDetection] Section Options
</title>
4046 <para>The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random
4047 Early Detection (GRED).
</para>
4049 <variablelist class='network-directives'
>
4050 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4051 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4054 <term><varname>VirtualQueues=
</varname></term>
4056 <para>Specifies the number of virtual queues. Takes an integer in the range
1…
16. Defaults to unset
4057 and kernel's default is used.
</para>
4062 <term><varname>DefaultVirtualQueue=
</varname></term>
4064 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
4065 Defaults to unset and kernel's default is used.
</para>
4070 <term><varname>GenericRIO=
</varname></term>
4072 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
4073 unset and kernel's default is used.
</para>
4080 <title>[FairQueueingControlledDelay] Section Options
</title>
4081 <para>The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing
4082 controlled delay (FQ-CoDel).
</para>
4084 <variablelist class='network-directives'
>
4085 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4086 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4089 <term><varname>PacketLimit=
</varname></term>
4091 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
4092 dropped. Defaults to unset and kernel's default is used.
</para>
4097 <term><varname>MemoryLimitBytes=
</varname></term>
4099 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
4100 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4101 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
4106 <term><varname>Flows=
</varname></term>
4108 <para>Specifies the number of flows into which the incoming packets are classified.
4109 Defaults to unset and kernel's default is used.
</para>
4114 <term><varname>TargetSec=
</varname></term>
4116 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
4117 Defaults to unset and kernel's default is used.
</para>
4122 <term><varname>IntervalSec=
</varname></term>
4124 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
4125 become too stale. Defaults to unset and kernel's default is used.
</para>
4130 <term><varname>QuantumBytes=
</varname></term>
4132 <para>Specifies the number of bytes used as the
"deficit" in the fair queuing algorithm timespan.
4133 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4134 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
4139 <term><varname>ECN=
</varname></term>
4141 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
4142 unset and kernel's default is used.
</para>
4147 <term><varname>CEThresholdSec=
</varname></term>
4149 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4150 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4157 <title>[FairQueueing] Section Options
</title>
4158 <para>The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing
4161 <variablelist class='network-directives'
>
4162 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4163 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4166 <term><varname>PacketLimit=
</varname></term>
4168 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
4169 dropped. Defaults to unset and kernel's default is used.
</para>
4174 <term><varname>FlowLimit=
</varname></term>
4176 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
4177 unset and kernel's default is used.
</para>
4182 <term><varname>QuantumBytes=
</varname></term>
4184 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
4185 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4186 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
4187 default is used.
</para>
4192 <term><varname>InitialQuantumBytes=
</varname></term>
4194 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
4195 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
4196 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
4197 kernel's default is used.
</para>
4202 <term><varname>MaximumRate=
</varname></term>
4204 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
4205 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
4206 1000. Defaults to unset and kernel's default is used.
</para>
4211 <term><varname>Buckets=
</varname></term>
4213 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
4214 kernel's default is used.
</para>
4219 <term><varname>OrphanMask=
</varname></term>
4221 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
4222 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
4223 kernel's default is used.
</para>
4228 <term><varname>Pacing=
</varname></term>
4230 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
4231 default is used.
</para>
4236 <term><varname>CEThresholdSec=
</varname></term>
4238 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4239 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4246 <title>[TrivialLinkEqualizer] Section Options
</title>
4247 <para>The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link
4248 equalizer (teql).
</para>
4250 <variablelist class='network-directives'
>
4251 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4252 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4255 <term><varname>Id=
</varname></term>
4257 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
4258 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
4259 <constant>max_equalizers=N+
1</constant> option must be loaded before
4260 <command>systemd-networkd
</command> is started.
</para>
4267 <title>[HierarchyTokenBucket] Section Options
</title>
4268 <para>The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token
4269 bucket (htb).
</para>
4271 <variablelist class='network-directives'
>
4272 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4273 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4276 <term><varname>DefaultClass=
</varname></term>
4278 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
4279 to the class. Defaults to unset.
</para>
4284 <term><varname>RateToQuantum=
</varname></term>
4286 <para>Takes an unsigned integer. The DRR quantums are calculated by dividing the value
4287 configured in
<varname>Rate=
</varname> by
<varname>RateToQuantum=
</varname>.
</para>
4294 <title>[HierarchyTokenBucketClass] Section Options
</title>
4295 <para>The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket
4298 <variablelist class='network-directives'
>
4299 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4300 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4303 <term><varname>Priority=
</varname></term>
4305 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
4306 priority field are tried for packets first.
</para>
4311 <term><varname>QuantumBytes=
</varname></term>
4313 <para>Specifies how many bytes to serve from leaf at once. When suffixed with K, M, or G, the
4314 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4320 <term><varname>MTUBytes=
</varname></term>
4322 <para>Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified
4323 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4328 <term><varname>OverheadBytes=
</varname></term>
4330 <para>Takes an unsigned integer which specifies per-packet size overhead used in rate
4331 computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4332 Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4337 <term><varname>Rate=
</varname></term>
4339 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
4340 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
4341 to the base of
1000. This setting is mandatory.
</para>
4346 <term><varname>CeilRate=
</varname></term>
4348 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
4349 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
4350 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
4356 <term><varname>BufferBytes=
</varname></term>
4358 <para>Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed
4359 with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
4360 to the base of
1024.
</para>
4365 <term><varname>CeilBufferBytes=
</varname></term>
4367 <para>Specifies the maximum bytes burst for ceil which can be accumulated during idle period.
4368 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4369 respectively, to the base of
1024.
</para>
4376 <title>[HeavyHitterFilter] Section Options
</title>
4377 <para>The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter
4380 <variablelist class='network-directives'
>
4381 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4382 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4385 <term><varname>PacketLimit=
</varname></term>
4387 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
4388 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
4389 kernel's default is used.
</para>
4396 <title>[QuickFairQueueing] Section Options
</title>
4397 <para>The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing
4400 <variablelist class='network-directives'
>
4401 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4402 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4407 <title>[QuickFairQueueingClass] Section Options
</title>
4408 <para>The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing
4411 <variablelist class='network-directives'
>
4412 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4413 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4416 <term><varname>Weight=
</varname></term>
4418 <para>Specifies the weight of the class. Takes an integer in the range
1…
1023. Defaults to
4419 unset in which case the kernel default is used.
</para>
4424 <term><varname>MaxPacketBytes=
</varname></term>
4426 <para>Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the
4427 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4428 1024. When unset, the kernel default is used.
</para>
4435 <title>[BridgeVLAN] Section Options
</title>
4436 <para>The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the
4437 following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The
4438 <varname>VLANFiltering=
</varname> option has to be enabled, see the [Bridge] section in
4439 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
4441 <variablelist class='network-directives'
>
4443 <term><varname>VLAN=
</varname></term>
4445 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. Takes
4446 an integer in the range
1…
4094.
</para>
4450 <term><varname>EgressUntagged=
</varname></term>
4452 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
4453 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
4454 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
4458 <term><varname>PVID=
</varname></term>
4460 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
4461 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
4462 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
4469 <title>Examples
</title>
4471 <title>Static network configuration
</title>
4473 <programlisting># /etc/systemd/network/
50-static.network
4478 Address=
192.168.0.15/
24
4479 Gateway=
192.168.0.1</programlisting>
4481 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
4482 specified gateway will be used for a default route.
</para>
4486 <title>DHCP on ethernet links
</title>
4488 <programlisting># /etc/systemd/network/
80-dhcp.network
4493 DHCP=yes
</programlisting>
4495 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
4496 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
4500 <title>IPv6 Prefix Delegation
</title>
4502 <programlisting># /etc/systemd/network/
55-ipv6-pd-upstream.network
4507 DHCP=ipv6
</programlisting>
4509 <programlisting># /etc/systemd/network/
56-ipv6-pd-downstream.network
4515 DHCPPrefixDelegation=yes
</programlisting>
4517 <para>This will enable DHCPv6-PD on the interface enp1s0 as an upstream interface where the
4518 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
4519 The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network.
4524 <title>A bridge with two enslaved links
</title>
4526 <programlisting># /etc/systemd/network/
25-bridge-static.network
4531 Address=
192.168.0.15/
24
4533 DNS=
192.168.0.1</programlisting>
4535 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
4540 Bridge=bridge0
</programlisting>
4542 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
4547 Bridge=bridge0
</programlisting>
4549 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
4550 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
4551 and network assigned, and a default route via the specified gateway will be
4552 added. The specified DNS server will be added to the global list of DNS resolvers.
4557 <title>Bridge port with VLAN forwarding
</title>
4560 # /etc/systemd/network/
25-bridge-slave-interface-
1.network
4576 EgressUntagged=
300-
400</programlisting>
4578 <para>This overrides the configuration specified in the previous example for the
4579 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
4580 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
4581 untagged when they leave on this interface. Untagged packets which arrive on this
4582 interface will be assigned VLAN ID
42.
</para>
4586 <title>Various tunnels
</title>
4588 <programlisting>/etc/systemd/network/
25-tunnels.network
4599 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
4605 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
4611 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
4617 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
4623 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
4624 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
4628 <title>A bond device
</title>
4630 <programlisting># /etc/systemd/network/
30-bond1.network
4638 <programlisting># /etc/systemd/network/
30-bond1.netdev
4644 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
4646 MACAddress=
52:
54:
00:e9:
64:
41
4652 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
4654 MACAddress=
52:
54:
00:e9:
64:
42
4660 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
4661 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
4662 will be used to acquire an address.
</para>
4666 <title>Virtual Routing and Forwarding (VRF)
</title>
4667 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
4668 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
4669 within the routing table defined during VRF creation. For kernels before
4.8 traffic
4670 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
4672 <programlisting># /etc/systemd/network/
25-vrf.network
4682 <title>MacVTap
</title>
4683 <para>This brings up a network interface
<literal>macvtap-test
</literal>
4684 and attaches it to
<literal>enp0s25
</literal>.
</para>
4685 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
4690 MACVTAP=macvtap-test
4695 <title>A Xfrm interface with physical underlying device.
</title>
4697 <programlisting># /etc/systemd/network/
27-xfrm.netdev
4703 InterfaceId=
7</programlisting>
4705 <programlisting># /etc/systemd/network/
27-eth0.network
4710 Xfrm=xfrm0
</programlisting>
4712 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
4713 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
4714 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
4720 <title>See Also
</title>
4722 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
4723 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
4724 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4725 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4726 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob