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=
"kind" />
89 <xi:include href=
"systemd.link.xml" xpointer=
"property" />
92 <term><varname>Name=
</varname></term>
94 <para>A whitespace-separated list of shell-style globs matching the device name, as exposed
95 by the udev property
<literal>INTERFACE
</literal>, or device's alternative names. If the
96 list is prefixed with a
"!", the test is inverted.
</para>
101 <term><varname>WLANInterfaceType=
</varname></term>
103 <para>A whitespace-separated list of wireless network type. Supported values are
104 <literal>ad-hoc
</literal>,
<literal>station
</literal>,
<literal>ap
</literal>,
105 <literal>ap-vlan
</literal>,
<literal>wds
</literal>,
<literal>monitor
</literal>,
106 <literal>mesh-point
</literal>,
<literal>p2p-client
</literal>,
<literal>p2p-go
</literal>,
107 <literal>p2p-device
</literal>,
<literal>ocb
</literal>, and
<literal>nan
</literal>. If the
108 list is prefixed with a
"!", the test is inverted.
</para>
113 <term><varname>SSID=
</varname></term>
115 <para>A whitespace-separated list of shell-style globs matching the SSID of the currently
116 connected wireless LAN. If the list is prefixed with a
"!", the test is inverted.
</para>
121 <term><varname>BSSID=
</varname></term>
123 <para>A whitespace-separated list of hardware address of the currently connected wireless
124 LAN. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example in
125 <varname>MACAddress=
</varname>. This option may appear more than once, in which case the
126 lists are merged. If the empty string is assigned to this option, the list is reset.
</para>
130 <xi:include href=
"systemd.link.xml" xpointer=
"host" />
131 <xi:include href=
"systemd.link.xml" xpointer=
"virtualization" />
132 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-command-line" />
133 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-version" />
134 <xi:include href=
"systemd.link.xml" xpointer=
"architecture" />
135 <xi:include href=
"systemd.link.xml" xpointer=
"firmware" />
140 <title>[Link] Section Options
</title>
142 <para>The [Link] section accepts the following keys:
</para>
144 <variablelist class='network-directives'
>
146 <term><varname>MACAddress=
</varname></term>
148 <para>The hardware address to set for the device.
</para>
153 <term><varname>MTUBytes=
</varname></term>
155 <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M,
156 G, are supported and are understood to the base of
1024.
</para>
157 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen below
1280 (the
158 minimum MTU for IPv6) it will automatically be increased to this value.
</para>
163 <term><varname>ARP=
</varname></term>
165 <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol)
166 for this interface is enabled. When unset, the kernel's default will be used.
</para>
167 <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
168 interfaces atop a single lower-level physical interface, which will then only serve as a
169 link/
"bridge" device aggregating traffic to the same physical link and not participate in
170 the network otherwise. Defaults to unset.
</para>
175 <term><varname>Multicast=
</varname></term>
177 <para>Takes a boolean. If set to true, the multicast flag on the device is enabled. Defaults
183 <term><varname>AllMulticast=
</varname></term>
185 <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the
186 network. This happens when multicast routing is enabled. Defaults to unset.
</para>
191 <term><varname>Promiscuous=
</varname></term>
193 <para>Takes a boolean. If set to true, promiscuous mode of the interface is enabled. Defaults
195 <para>If this is set to false for the underlying link of a
<literal>passthru
</literal> mode
196 MACVLAN/MACVTAP, the virtual interface will be created with the
<literal>nopromisc
</literal>
202 <term><varname>Unmanaged=
</varname></term>
204 <para>Takes a boolean. When
<literal>yes
</literal>, no attempts are made to bring up or
205 configure matching links, equivalent to when there are no matching network files. Defaults to
206 <literal>no
</literal>.
</para>
207 <para>This is useful for preventing later matching network files from interfering with
208 certain interfaces that are fully controlled by other applications.
</para>
213 <term><varname>Group=
</varname></term>
215 <para>Link groups are similar to port ranges found in managed switches. When network
216 interfaces are added to a numbered group, operations on all the interfaces from that group
217 can be performed at once. Takes an unsigned integer in the range
0…
2147483647. Defaults to
223 <term><varname>RequiredForOnline=
</varname></term>
225 <para>Takes a boolean or a minimum operational state and an optional maximum operational
227 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
228 for possible operational states. When
<literal>yes
</literal>, the network is deemed required
229 when determining whether the system is online (including when running
230 <command>systemd-networkd-wait-online
</command>). When
<literal>no
</literal>, the network is
231 ignored when determining the online state. When a minimum operational state and an optional
232 maximum operational state are set,
<literal>yes
</literal> is implied, and this controls the
233 minimum and maximum operational state required for the network interface to be considered
236 <para>Defaults to
<literal>yes
</literal> when
<varname>ActivationPolicy=
</varname> is not
237 set, or set to
<literal>up
</literal>,
<literal>always-up
</literal>, or
238 <literal>bound
</literal>. Defaults to
<literal>no
</literal> when
239 <varname>ActivationPolicy=
</varname> is set to
<literal>manual
</literal> or
240 <literal>down
</literal>. This is forced to
<literal>no
</literal> when
241 <varname>ActivationPolicy=
</varname> is set to
<literal>always-down
</literal>.
</para>
243 <para>The network will be brought up normally (as configured by
244 <varname>ActivationPolicy=
</varname>), but in the event that there is no address being
245 assigned by DHCP or the cable is not plugged in, the link will simply remain offline and be
246 skipped automatically by
<command>systemd-networkd-wait-online
</command> if
247 <literal>RequiredForOnline=no
</literal>.
</para>
252 <term><varname>RequiredFamilyForOnline=
</varname></term>
254 <para>Takes an address family. When specified, an IP address in the given family is deemed
255 required when determining whether the link is online (including when running
256 <command>systemd-networkd-wait-online
</command>). Takes one of
<literal>ipv4
</literal>,
257 <literal>ipv6
</literal>,
<literal>both
</literal>, or
<literal>any
</literal>. Defaults to
258 <literal>any
</literal>. Note that this option has no effect if
259 <literal>RequiredForOnline=no
</literal>, or if
<literal>RequiredForOnline=
</literal>
260 specifies a minimum operational state below
<literal>degraded
</literal>.
</para>
265 <term><varname>ActivationPolicy=
</varname></term>
267 <para>Specifies the policy for
<command>systemd-networkd
</command> managing the link
268 administrative state. Specifically, this controls how
<command>systemd-networkd
</command>
269 changes the network device's
<literal>IFF_UP
</literal> flag, which is sometimes
270 controlled by system administrators by running e.g.,
271 <command>ip link set dev eth0 up
</command> or
<command>ip link set dev eth0 down
</command>,
272 and can also be changed with
<command>networkctl up eth0
</command> or
273 <command>networkctl down eth0
</command>.
</para>
275 <para>Takes one of
<literal>up
</literal>,
<literal>always-up
</literal>,
276 <literal>manual
</literal>,
<literal>always-down
</literal>,
<literal>down
</literal>,
277 or
<literal>bound
</literal>. When
<literal>manual
</literal>,
278 <command>systemd-networkd
</command> will not change the link's admin state automatically;
279 the system administrator must bring the interface up or down manually, as desired. When
280 <literal>up
</literal> (the default) or
<literal>always-up
</literal>, or
281 <literal>down
</literal> or
<literal>always-down
</literal>,
282 <command>systemd-networkd
</command> will set the link up or down, respectively, when the
283 interface is (re)configured. When
<literal>always-up
</literal> or
284 <literal>always-down
</literal>,
<command>systemd-networkd
</command> will set the link up or
285 down, respectively, any time
<command>systemd-networkd
</command> detects a change in the
286 administrative state. When
<varname>BindCarrier=
</varname> is also set, this is automatically
287 set to
<literal>bound
</literal> and any other value is ignored.
</para>
289 <para>When the policy is set to
<literal>down
</literal> or
<literal>manual
</literal>, the
290 default value of
<varname>RequiredForOnline=
</varname> is
<literal>no
</literal>. When the
291 policy is set to
<literal>always-down
</literal>, the value of
292 <varname>RequiredForOnline=
</varname> forced to
<literal>no
</literal>.
</para>
294 <para>The administrative state is not the same as the carrier state, so using
295 <literal>always-up
</literal> does not mean the link will never lose carrier. The link carrier
296 depends on both the administrative state as well as the network device's physical connection.
297 However, to avoid reconfiguration failures, when using
<literal>always-up
</literal>,
298 <varname>IgnoreCarrierLoss=
</varname> is forced to true.
</para>
304 <xi:include href=
"systemd.link.xml" xpointer=
"sr-iov" />
307 <title>[Network] Section Options
</title>
309 <para>The [Network] section accepts the following keys:
</para>
311 <variablelist class='network-directives'
>
313 <term><varname>Description=
</varname></term>
315 <para>A description of the device. This is only used for presentation purposes.
</para>
320 <term><varname>DHCP=
</varname></term>
322 <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
<literal>yes
</literal>,
323 <literal>no
</literal>,
<literal>ipv4
</literal>, or
<literal>ipv6
</literal>. Defaults to
324 <literal>no
</literal>.
</para>
326 <para>Note that DHCPv6 will by default be triggered by Router Advertisement, if that is
327 enabled, regardless of this parameter. By enabling DHCPv6 support explicitly, the DHCPv6
328 client will be started regardless of the presence of routers on the link, or what flags the
329 routers pass. See
<literal>IPv6AcceptRA=
</literal>.
</para>
331 <para>Furthermore, note that by default the domain name specified through DHCP is not used
332 for name resolution. See option
<option>UseDomains=
</option> below.
</para>
334 <para>See the [DHCPv4] or [DHCPv6] sections below for further configuration options for the
335 DHCP client support.
</para>
340 <term><varname>DHCPServer=
</varname></term>
342 <para>Takes a boolean. If set to
<literal>yes
</literal>, DHCPv4 server will be started.
343 Defaults to
<literal>no
</literal>. Further settings for the DHCP server may be set in the
344 [DHCPServer] section described below.
</para>
349 <term><varname>LinkLocalAddressing=
</varname></term>
351 <para>Enables link-local address autoconfiguration. Accepts
<option>yes
</option>,
352 <option>no
</option>,
<option>ipv4
</option>, and
<option>ipv6
</option>. An IPv6 link-local
353 address is configured when
<option>yes
</option> or
<option>ipv6
</option>. An IPv4 link-local
354 address is configured when
<option>yes
</option> or
<option>ipv4
</option> and when DHCPv4
355 autoconfiguration has been unsuccessful for some time. (IPv4 link-local address
356 autoconfiguration will usually happen in parallel with repeated attempts to acquire a DHCPv4
359 <para>Defaults to
<option>no
</option> when
<varname>KeepMaster=
</varname> or
360 <varname>Bridge=
</varname> is set or when the specified
361 <varname>MACVLAN=
</varname>/
<varname>MACVTAP=
</varname> has
<varname>Mode=passthru
</varname>,
362 or
<option>ipv6
</option> otherwise.
</para>
367 <term><varname>IPv6LinkLocalAddressGenerationMode=
</varname></term>
369 <para>Specifies how IPv6 link local address is generated. Takes one of
370 <literal>eui64
</literal>,
<literal>none
</literal>,
<literal>stable-privacy
</literal> and
371 <literal>random
</literal>. When unset,
<literal>stable-privacy
</literal> is used if
372 <varname>IPv6StableSecretAddress=
</varname> is specified, and if not,
373 <literal>eui64
</literal> is used. Note that if
<varname>LinkLocalAddressing=
</varname> is
374 <literal>no
</literal> or
<literal>ipv4
</literal>, then
375 <varname>IPv6LinkLocalAddressGenerationMode=
</varname> will be ignored. Also, even if
376 <varname>LinkLocalAddressing=
</varname> is
<literal>yes
</literal> or
<literal>ipv6
</literal>,
377 setting
<varname>IPv6LinkLocalAddressGenerationMode=none
</varname>
378 disables to configure an IPv6 link-local address.
</para>
383 <term><varname>IPv6StableSecretAddress=
</varname></term>
385 <para>Takes an IPv6 address. The specified address will be used as a stable secret for
386 generating IPv6 link-local address. If this setting is specified, and
387 <varname>IPv6LinkLocalAddressGenerationMode=
</varname> is unset, then
388 <varname>IPv6LinkLocalAddressGenerationMode=stable-privacy
</varname> is implied.
389 If this setting is not specified, and
<literal>stable-privacy
</literal> is set to
390 <varname>IPv6LinkLocalAddressGenerationMode=
</varname>,
391 then a stable secret address will be generated from the local machine ID and the interface
397 <term><varname>IPv4LLRoute=
</varname></term>
399 <para>Takes a boolean. If set to true, sets up the route needed for non-IPv4LL hosts to
400 communicate with IPv4LL-only hosts. Defaults to false.
</para>
405 <term><varname>DefaultRouteOnDevice=
</varname></term>
407 <para>Takes a boolean. If set to true, sets up the default route bound to the interface.
408 Defaults to false. This is useful when creating routes on point-to-point interfaces. This is
409 equivalent to e.g. the following,
410 <programlisting>ip route add default dev veth99
</programlisting>
412 <programlisting>[Route]
413 Gateway=
0.0.0.0</programlisting></para>
414 <para>Currently, there are no way to specify e.g., the table for the route configured by this
415 setting. To configure the default route with such an additional property, please use the
417 <programlisting>[Route]
419 Table=
1234</programlisting></para>
424 <term><varname>LLMNR=
</varname></term>
426 <para>Takes a boolean or
<literal>resolve
</literal>. When true, enables
427 <ulink url=
"https://tools.ietf.org/html/rfc4795">Link-Local Multicast Name Resolution
</ulink>
428 on the link. When set to
<literal>resolve
</literal>, only resolution is enabled, but not host
429 registration and announcement. Defaults to true. This setting is read by
430 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
436 <term><varname>MulticastDNS=
</varname></term>
438 <para>Takes a boolean or
<literal>resolve
</literal>. When true, enables
439 <ulink url=
"https://tools.ietf.org/html/rfc6762">Multicast DNS
</ulink> support on the link.
440 When set to
<literal>resolve
</literal>, only resolution is enabled, but not host or service
441 registration and announcement. Defaults to false. This setting is read by
442 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
448 <term><varname>DNSOverTLS=
</varname></term>
450 <para>Takes a boolean or
<literal>opportunistic
</literal>. When true, enables
451 <ulink url=
"https://tools.ietf.org/html/rfc7858">DNS-over-TLS
</ulink> support on the link.
452 When set to
<literal>opportunistic
</literal>, compatibility with non-DNS-over-TLS servers is
453 increased, by automatically turning off DNS-over-TLS servers in this case. This option
454 defines a per-interface setting for
455 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
456 global
<varname>DNSOverTLS=
</varname> option. Defaults to unset, and the global setting will
457 be used. This setting is read by
458 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
464 <term><varname>DNSSEC=
</varname></term>
466 <para>Takes a boolean or
<literal>allow-downgrade
</literal>. When true, enables
467 <ulink url=
"https://tools.ietf.org/html/rfc4033">DNSSEC
</ulink> DNS validation support on the
468 link. When set to
<literal>allow-downgrade
</literal>, compatibility with non-DNSSEC capable
469 networks is increased, by automatically turning off DNSSEC in this case. This option defines
470 a per-interface setting for
471 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
472 global
<varname>DNSSEC=
</varname> option. Defaults to unset, and the global setting will be
473 used. This setting is read by
474 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
480 <term><varname>DNSSECNegativeTrustAnchors=
</varname></term>
482 <para>A space-separated list of DNSSEC negative trust anchor domains. If specified and DNSSEC
483 is enabled, look-ups done via the interface's DNS server will be subject to the list of
484 negative trust anchors, and not require authentication for the specified domains, or anything
485 below it. Use this to disable DNSSEC authentication for specific private domains, that cannot
486 be proven valid using the Internet DNS hierarchy. Defaults to the empty list. This setting is
488 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
494 <term><varname>LLDP=
</varname></term>
496 <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol
497 commonly implemented on professional routers and bridges which announces which physical port
498 a system is connected to, as well as other related data. Accepts a boolean or the special
499 value
<literal>routers-only
</literal>. When true, incoming LLDP packets are accepted and a
500 database of all LLDP neighbors maintained. If
<literal>routers-only
</literal> is set only
501 LLDP data of various types of routers is collected and LLDP data about other types of devices
502 ignored (such as stations, telephones and others). If false, LLDP reception is disabled.
503 Defaults to
<literal>routers-only
</literal>. Use
504 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
505 to query the collected neighbor data. LLDP is only available on Ethernet links. See
506 <varname>EmitLLDP=
</varname> below for enabling LLDP packet emission from the local system.
512 <term><varname>EmitLLDP=
</varname></term>
514 <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the
515 special values
<literal>nearest-bridge
</literal>,
<literal>non-tpmr-bridge
</literal> and
516 <literal>customer-bridge
</literal>. Defaults to false, which turns off LLDP packet emission.
517 If not false, a short LLDP packet with information about the local system is sent out in
518 regular intervals on the link. The LLDP packet will contain information about the local
519 hostname, the local machine ID (as stored in
520 <citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
521 and the local interface name, as well as the pretty hostname of the system (as set in
522 <citerefentry><refentrytitle>machine-info
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
523 LLDP emission is only available on Ethernet links. Note that this setting passes data
524 suitable for identification of host to the network and should thus not be enabled on
525 untrusted networks, where such identification data should not be made available. Use this
526 option to permit other systems to identify on which interfaces they are connected to this
527 system. The three special values control propagation of the LLDP packets. The
528 <literal>nearest-bridge
</literal> setting permits propagation only to the nearest connected
529 bridge,
<literal>non-tpmr-bridge
</literal> permits propagation across Two-Port MAC Relays,
530 but not any other bridges, and
<literal>customer-bridge
</literal> permits propagation until
531 a customer bridge is reached. For details about these concepts, see
532 <ulink url=
"https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE
802.1AB-
2016</ulink>.
533 Note that configuring this setting to true is equivalent to
534 <literal>nearest-bridge
</literal>, the recommended and most restricted level of propagation.
535 See
<varname>LLDP=
</varname> above for an option to enable LLDP reception.
</para>
540 <term><varname>BindCarrier=
</varname></term>
542 <para>A link name or a list of link names. When set, controls the behavior of the current
543 link. When all links in the list are in an operational down state, the current link is
544 brought down. When at least one link has carrier, the current interface is brought up.
</para>
546 <para>This forces
<varname>ActivationPolicy=
</varname> to be set to
<literal>bound
</literal>.
552 <term><varname>Address=
</varname></term>
554 <para>A static IPv4 or IPv6 address and its prefix length, separated by a
555 <literal>/
</literal> character. Specify this key more than once to configure several
556 addresses. The format of the address must be as described in
557 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
558 This is a short-hand for an [Address] section only containing an Address key (see below).
559 This option may be specified more than once.
</para>
561 <para>If the specified address is
<literal>0.0.0.0</literal> (for IPv4) or
562 <literal>::
</literal> (for IPv6), a new address range of the requested size is automatically
563 allocated from a system-wide pool of unused ranges. Note that the prefix length must be equal
564 or larger than
8 for IPv4, and
64 for IPv6. The allocated range is checked against all
565 current network interfaces and all known network configuration files to avoid address range
566 conflicts. The default system-wide pool consists of
192.168.0.0/
16,
172.16.0.0/
12 and
567 10.0.0.0/
8 for IPv4, and fd00::/
8 for IPv6. This functionality is useful to manage a large
568 number of dynamically created network interfaces with the same network configuration and
569 automatic address range assignment.
</para>
574 <term><varname>Gateway=
</varname></term>
576 <para>The gateway address, which must be in the format described in
577 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
578 This is a short-hand for a [Route] section only containing a
<varname>Gateway=
</varname> key.
579 This option may be specified more than once.
</para>
584 <term><varname>DNS=
</varname></term>
586 <para>A DNS server address, which must be in the format described in
587 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
588 This option may be specified more than once. Each address can optionally take a port number
589 separated with
<literal>:
</literal>, a network interface name or index separated with
590 <literal>%
</literal>, and a Server Name Indication (SNI) separated with
<literal>#
</literal>.
591 When IPv6 address is specified with a port number, then the address must be in the square
592 brackets. That is, the acceptable full formats are
593 <literal>111.222.333.444:
9953%ifname#example.com
</literal> for IPv4 and
594 <literal>[
1111:
2222::
3333]:
9953%ifname#example.com
</literal> for IPv6. If an empty string is
595 assigned, then the all previous assignments are cleared. This setting is read by
596 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
602 <term><varname>Domains=
</varname></term>
604 <para>A whitespace-separated list of domains which should be resolved using the DNS servers
605 on this link. Each item in the list should be a domain name, optionally prefixed with a tilde
606 (
<literal>~
</literal>). The domains with the prefix are called
"routing-only domains". The
607 domains without the prefix are called
"search domains" and are first used as search suffixes
608 for extending single-label hostnames (hostnames containing no dots) to become fully qualified
609 domain names (FQDNs). If a single-label hostname is resolved on this interface, each of the
610 specified search domains are appended to it in turn, converting it into a fully qualified
611 domain name, until one of them may be successfully resolved.
</para>
613 <para>Both
"search" and
"routing-only" domains are used for routing of DNS queries: look-ups
614 for hostnames ending in those domains (hence also single label names, if any
"search domains"
615 are listed), are routed to the DNS servers configured for this interface. The domain routing
616 logic is particularly useful on multi-homed hosts with DNS servers serving particular private
617 DNS zones on each interface.
</para>
619 <para>The
"routing-only" domain
<literal>~.
</literal> (the tilde indicating definition of a
620 routing domain, the dot referring to the DNS root domain which is the implied suffix of all
621 valid DNS names) has special effect. It causes all DNS traffic which does not match another
622 configured domain routing entry to be routed to DNS servers specified for this interface.
623 This setting is useful to prefer a certain set of DNS servers if a link on which they are
624 connected is available.
</para>
626 <para>This setting is read by
627 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
628 "Search domains" correspond to the
<varname>domain
</varname> and
<varname>search
</varname>
630 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
631 Domain name routing has no equivalent in the traditional glibc API, which has no concept of
632 domain name servers limited to a specific link.
</para>
637 <term><varname>DNSDefaultRoute=
</varname></term>
639 <para>Takes a boolean argument. If true, this link's configured DNS servers are used for
640 resolving domain names that do not match any link's configured
<varname>Domains=
</varname>
641 setting. If false, this link's configured DNS servers are never used for such domains, and
642 are exclusively used for resolving names that match at least one of the domains configured on
643 this link. If not specified defaults to an automatic mode: queries not matching any link's
644 configured domains will be routed to this link if it has no routing-only domains configured.
650 <term><varname>NTP=
</varname></term>
652 <para>An NTP server address (either an IP address, or a hostname). This option may be
653 specified more than once. This setting is read by
654 <citerefentry><refentrytitle>systemd-timesyncd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
660 <term><varname>IPForward=
</varname></term>
662 <para>Configures IP packet forwarding for the system. If enabled, incoming packets on any
663 network interface will be forwarded to any other interfaces according to the routing table.
664 Takes a boolean, or the values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>, which only
665 enable IP packet forwarding for the specified address family. This controls the
666 <filename>net.ipv4.ip_forward
</filename> and
<filename>net.ipv6.conf.all.forwarding
</filename>
667 sysctl options of the network interface (see
668 <ulink url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
669 for details about sysctl options). Defaults to
<literal>no
</literal>.
</para>
671 <para>Note: this setting controls a global kernel option, and does so one way only: if a
672 network that has this setting enabled is set up the global setting is turned on. However,
673 it is never turned off again, even after all networks with this setting enabled are shut
676 <para>To allow IP packet forwarding only between specific network interfaces use a firewall.
682 <term><varname>IPMasquerade=
</varname></term>
684 <para>Configures IP masquerading for the network interface. If enabled, packets forwarded
685 from the network interface will be appear as coming from the local host. Takes one of
686 <literal>ipv4
</literal>,
<literal>ipv6
</literal>,
<literal>both
</literal>, or
687 <literal>no
</literal>. Defaults to
<literal>no
</literal>. If enabled, this automatically sets
688 <varname>IPForward=
</varname> to one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal> or
689 <literal>yes
</literal>.
</para>
690 <para>Note. Any positive boolean values such as
<literal>yes
</literal> or
691 <literal>true
</literal> are now deprecated. Please use one of the values in the above.
</para>
696 <term><varname>IPv6PrivacyExtensions=
</varname></term>
698 <para>Configures use of stateless temporary addresses that change over time (see
699 <ulink url=
"https://tools.ietf.org/html/rfc4941">RFC
4941</ulink>,
700 Privacy Extensions for Stateless Address Autoconfiguration in IPv6). Takes a boolean or the
701 special values
<literal>prefer-public
</literal> and
<literal>kernel
</literal>. When true,
702 enables the privacy extensions and prefers temporary addresses over public addresses. When
703 <literal>prefer-public
</literal>, enables the privacy extensions, but prefers public
704 addresses over temporary addresses. When false, the privacy extensions remain disabled. When
705 <literal>kernel
</literal>, the kernel's default setting will be left in place. Defaults to
706 <literal>no
</literal>.
</para>
711 <term><varname>IPv6AcceptRA=
</varname></term>
713 <para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the
714 interface. If true, RAs are accepted; if false, RAs are ignored. When RAs are accepted, they
715 may trigger the start of the DHCPv6 client if the relevant flags are set in the RA data, or
716 if no routers are found on the link. The default is to disable RA reception for bridge
717 devices or when IP forwarding is enabled, and to enable it otherwise. Cannot be enabled on
718 bond devices and when link local addressing is disabled.
</para>
720 <para>Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA]
721 section, see below.
</para>
724 <ulink url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
725 in the kernel documentation regarding
<literal>accept_ra
</literal>, but note that systemd's
726 setting of
<constant>1</constant> (i.e. true) corresponds to kernel's setting of
727 <constant>2</constant>.
</para>
729 <para>Note that kernel's implementation of the IPv6 RA protocol is always disabled,
730 regardless of this setting. If this option is enabled, a userspace implementation of the IPv6
731 RA protocol is used, and the kernel's own implementation remains disabled, since
732 <command>systemd-networkd
</command> needs to know all details supplied in the advertisements,
733 and these are not available from the kernel if the kernel's own implementation is used.
739 <term><varname>IPv6DuplicateAddressDetection=
</varname></term>
741 <para>Configures the amount of IPv6 Duplicate Address Detection (DAD) probes to send. When
742 unset, the kernel's default will be used.
</para>
747 <term><varname>IPv6HopLimit=
</varname></term>
749 <para>Configures IPv6 Hop Limit. For each router that forwards the packet, the hop limit is
750 decremented by
1. When the hop limit field reaches zero, the packet is discarded. When unset,
751 the kernel's default will be used.
</para>
756 <term><varname>IPv4AcceptLocal=
</varname></term>
758 <para>Takes a boolean. Accept packets with local source addresses. In combination with
759 suitable routing, this can be used to direct packets between two local interfaces over the
760 wire and have them accepted properly. When unset, the kernel's default will be used.
</para>
765 <term><varname>IPv4RouteLocalnet=
</varname></term>
767 <para>Takes a boolean. When true, the kernel does not consider loopback addresses as martian
768 source or destination while routing. This enables the use of
127.0.0.0/
8 for local routing
769 purposes. When unset, the kernel's default will be used.
</para>
774 <term><varname>IPv4ProxyARP=
</varname></term>
776 <para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one
777 host, usually a router, answers ARP requests intended for another machine. By
"faking" its
778 identity, the router accepts responsibility for routing packets to the
"real" destination.
779 See
<ulink url=
"https://tools.ietf.org/html/rfc1027">RFC
1027</ulink>. When unset, the
780 kernel's default will be used.
</para>
785 <term><varname>IPv6ProxyNDP=
</varname></term>
787 <para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery Protocol)
788 is a technique for IPv6 to allow routing of addresses to a different destination when peers
789 expect them to be present on a certain physical link. In this case a router answers Neighbour
790 Advertisement messages intended for another machine by offering its own MAC address as
791 destination. Unlike proxy ARP for IPv4, it is not enabled globally, but will only send
792 Neighbour Advertisement messages for addresses in the IPv6 neighbor proxy table, which can
793 also be shown by
<command>ip -
6 neighbour show proxy
</command>. systemd-networkd will control
794 the per-interface `proxy_ndp` switch for each configured interface depending on this option.
795 When unset, the kernel's default will be used.
</para>
800 <term><varname>IPv6ProxyNDPAddress=
</varname></term>
802 <para>An IPv6 address, for which Neighbour Advertisement messages will be proxied. This
803 option may be specified more than once. systemd-networkd will add the
804 <varname>IPv6ProxyNDPAddress=
</varname> entries to the kernel's IPv6 neighbor proxy table.
805 This setting implies
<varname>IPv6ProxyNDP=yes
</varname> but has no effect if
806 <varname>IPv6ProxyNDP=
</varname> has been set to false. When unset, the kernel's default will
812 <term><varname>IPv6SendRA=
</varname></term>
814 <para>Whether to enable or disable Router Advertisement sending on a link. Takes a boolean
815 value. When enabled, prefixes configured in [IPv6Prefix] sections and routes configured in
816 the [IPv6RoutePrefix] sections are distributed as defined in the [IPv6SendRA] section. If
817 <varname>DHCPPrefixDelegation=
</varname> is enabled, then the delegated prefixes are also
818 distributed. See
<varname>DCHPPrefixDelegation=
</varname> setting and the [IPv6SendRA],
819 [IPv6Prefix], [IPv6RoutePrefix], and [DHCPPrefixDelegation] sections for more configuration
825 <term><varname>DHCPPrefixDelegation=
</varname></term>
827 <para>Takes a boolean value. When enabled, requests subnet prefixes on another link via the DHCPv6
828 protocol or via the
6RD option in the DHCPv4 protocol. An address within each delegated prefix will
829 be assigned, and the prefixes will be announced through IPv6 Router Advertisement if
830 <varname>IPv6SendRA=
</varname> is enabled. This behaviour can be configured in the
831 [DHCPPrefixDelegation] section. Defaults to disabled.
</para>
836 <term><varname>IPv6MTUBytes=
</varname></term>
838 <para>Configures IPv6 maximum transmission unit (MTU). An integer greater than or equal to
839 1280 bytes. When unset, the kernel's default will be used.
</para>
844 <term><varname>KeepMaster=
</varname></term>
846 <para>Takes a boolean value. When enabled, the current master interface index will not be
847 changed, and
<varname>BatmanAdvanced=
</varname>,
<varname>Bond=
</varname>,
848 <varname>Bridge=
</varname>, and
<varname>VRF=
</varname> settings are ignored. This may be
849 useful when a netdev with a master interface is created by another program, e.g.
850 <citerefentry><refentrytitle>systemd-nspawn
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
851 Defaults to false.
</para>
856 <term><varname>BatmanAdvanced=
</varname></term>
857 <term><varname>Bond=
</varname></term>
858 <term><varname>Bridge=
</varname></term>
859 <term><varname>VRF=
</varname></term>
861 <para>The name of the B.A.T.M.A.N. Advanced, bond, bridge, or VRF interface to add the link
863 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
869 <term><varname>IPoIB=
</varname></term>
870 <term><varname>IPVLAN=
</varname></term>
871 <term><varname>IPVTAP=
</varname></term>
872 <term><varname>L2TP=
</varname></term>
873 <term><varname>MACsec=
</varname></term>
874 <term><varname>MACVLAN=
</varname></term>
875 <term><varname>MACVTAP=
</varname></term>
876 <term><varname>Tunnel=
</varname></term>
877 <term><varname>VLAN=
</varname></term>
878 <term><varname>VXLAN=
</varname></term>
879 <term><varname>Xfrm=
</varname></term>
881 <para>The name of an IPoIB, IPVLAN, IPVTAP, L2TP, MACsec, MACVLAN, MACVTAP, tunnel, VLAN,
882 VXLAN, or Xfrm to be created on the link. See
883 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
884 This option may be specified more than once.
</para>
889 <term><varname>ActiveSlave=
</varname></term>
891 <para>Takes a boolean. Specifies the new active slave. The
<literal>ActiveSlave=
</literal>
892 option is only valid for following modes:
<literal>active-backup
</literal>,
893 <literal>balance-alb
</literal>, and
<literal>balance-tlb
</literal>. Defaults to false.
</para>
898 <term><varname>PrimarySlave=
</varname></term>
900 <para>Takes a boolean. Specifies which slave is the primary device. The specified device will
901 always be the active slave while it is available. Only when the primary is off-line will
902 alternate devices be used. This is useful when one slave is preferred over another, e.g.
903 when one slave has higher throughput than another. The
<literal>PrimarySlave=
</literal>
904 option is only valid for following modes:
<literal>active-backup
</literal>,
905 <literal>balance-alb
</literal>, and
<literal>balance-tlb
</literal>. Defaults to false.
</para>
910 <term><varname>ConfigureWithoutCarrier=
</varname></term>
912 <para>Takes a boolean. Allows networkd to configure a specific link even if it has no
913 carrier. Defaults to false. If enabled, and the
<varname>IgnoreCarrierLoss=
</varname> setting
914 is not explicitly set, then it is enabled as well.
</para>
919 <term><varname>IgnoreCarrierLoss=
</varname></term>
921 <para>Takes a boolean or a timespan. When true, networkd retains both the static and dynamic
922 configuration of the interface even if its carrier is lost. When a timespan is specified,
923 networkd waits for the specified timespan, and ignores the carrier loss if the link regain
924 its carrier within the timespan. Setting a finite timespan may be useful for a wireless
925 interface connecting to a network which has multiple access points with the same SSID, or an
926 interface which is reset on changing MTU. When unset, the value specified with
927 <varname>ConfigureWithoutCarrier=
</varname> is used.
</para>
929 <para>When
<varname>ActivationPolicy=
</varname> is set to
<literal>always-up
</literal>, this
930 is forced to
<literal>true
</literal>.
936 <term><varname>KeepConfiguration=
</varname></term>
938 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
939 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
940 will not drop static addresses and routes on starting up process. When set to
941 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
942 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
943 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
944 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
945 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
946 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
947 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
948 <literal>dhcp-on-stop
</literal> when
<command>systemd-networkd
</command> is running in
949 initrd,
<literal>yes
</literal> when the root filesystem is a network filesystem, and
950 <literal>no
</literal> otherwise.
</para>
957 <title>[Address] Section Options
</title>
959 <para>An [Address] section accepts the following keys. Specify several [Address] sections to
960 configure several addresses.
</para>
962 <variablelist class='network-directives'
>
964 <term><varname>Address=
</varname></term>
966 <para>As in the [Network] section. This setting is mandatory. Each [Address] section can
967 contain one
<varname>Address=
</varname> setting.
</para>
972 <term><varname>Peer=
</varname></term>
974 <para>The peer address in a point-to-point connection. Accepts the same format as the
975 <varname>Address=
</varname> setting.
</para>
980 <term><varname>Broadcast=
</varname></term>
982 <para>Takes an IPv4 address or boolean value. The address must be in the format described in
983 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
984 If set to true, then the IPv4 broadcast address will be derived from the
985 <varname>Address=
</varname> setting. If set to false, then the broadcast address will not be
986 set. Defaults to true, except for wireguard interfaces, where it default to false.
</para>
991 <term><varname>Label=
</varname></term>
993 <para>Specifies the label for the IPv4 address. The label must be a
7-bit ASCII string with
994 a length of
1…
15 characters. Defaults to unset.
</para>
999 <term><varname>PreferredLifetime=
</varname></term>
1001 <para>Allows the default
"preferred lifetime" of the address to be overridden. Only three
1002 settings are accepted:
<literal>forever
</literal>,
<literal>infinity
</literal>, which is the
1003 default and means that the address never expires, and
<literal>0</literal>, which means that
1004 the address is considered immediately
"expired" and will not be used, unless explicitly
1005 requested. A setting of
<option>PreferredLifetime=
0</option> is useful for addresses which
1006 are added to be used only by a specific application, which is then configured to use them
1012 <term><varname>Scope=
</varname></term>
1014 <para>The scope of the address, which can be
<literal>global
</literal> (valid everywhere on
1015 the network, even through a gateway),
<literal>link
</literal> (only valid on this device,
1016 will not traverse a gateway) or
<literal>host
</literal> (only valid within the device itself,
1017 e.g.
127.0.0.1) or an integer in the range
0…
255. Defaults to
<literal>global
</literal>.
1023 <term><varname>RouteMetric=
</varname></term>
1025 <para>The metric of the prefix route, which is pointing to the subnet of the configured IP
1026 address, taking the configured prefix length into account. Takes an unsigned integer in the
1027 range
0…
4294967295. When unset or set to
0, the kernel's default value is used. This
1028 setting will be ignored when
<varname>AddPrefixRoute=
</varname> is false.
</para>
1033 <term><varname>HomeAddress=
</varname></term>
1035 <para>Takes a boolean. Designates this address the
"home address" as defined in
1036 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>. Supported only on IPv6.
1037 Defaults to false.
</para>
1042 <term><varname>DuplicateAddressDetection=
</varname></term>
1044 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
<literal>both
</literal>,
1045 or
<literal>none
</literal>. When
<literal>ipv4
</literal>, performs IPv4 Address Conflict
1046 Detection. See
<ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>.
1047 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
1048 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>. Defaults to
1049 <literal>ipv6
</literal>.
</para>
1054 <term><varname>ManageTemporaryAddress=
</varname></term>
1056 <para>Takes a boolean. If true the kernel manage temporary addresses created from this one as
1057 template on behalf of Privacy Extensions
1058 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become active,
1059 the use_tempaddr sysctl setting has to be set to a value greater than zero. The given address
1060 needs to have a prefix length of
64. This flag allows using privacy extensions in a manually
1061 configured network, just like if stateless auto-configuration was active. Defaults to false.
1067 <term><varname>AddPrefixRoute=
</varname></term>
1069 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
1070 Defaults to true.
</para>
1075 <term><varname>AutoJoin=
</varname></term>
1077 <para>Takes a boolean. Joining multicast group on ethernet level via
1078 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
1079 IGMP snooping since the switch would not replicate multicast packets on ports that did not
1080 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
1081 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
1082 that enables then to do the required join. By extending ip address command with option
1083 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
1084 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
1085 Defaults to
<literal>no
</literal>.
</para>
1092 <title>[Neighbor] Section Options
</title>
1094 <para>A [Neighbor] section accepts the following keys. The neighbor section adds a permanent,
1095 static entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the
1096 links matched for the network. Specify several [Neighbor] sections to configure several static
1099 <variablelist class='network-directives'
>
1101 <term><varname>Address=
</varname></term>
1103 <para>The IP address of the neighbor.
</para>
1108 <term><varname>LinkLayerAddress=
</varname></term>
1110 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1117 <title>[IPv6AddressLabel] Section Options
</title>
1119 <para>An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel]
1120 sections to configure several address labels. IPv6 address labels are used for address selection.
1121 See
<ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>. Precedence is managed by
1122 userspace, and only the label itself is stored in the kernel.
</para>
1124 <variablelist class='network-directives'
>
1126 <term><varname>Label=
</varname></term>
1128 <para>The label for the prefix, an unsigned integer in the range
0…
4294967294.
0xffffffff is
1129 reserved. This setting is mandatory.
</para>
1134 <term><varname>Prefix=
</varname></term>
1136 <para>IPv6 prefix is an address with a prefix length, separated by a slash
1137 <literal>/
</literal> character. This setting is mandatory.
</para>
1144 <title>[RoutingPolicyRule] Section Options
</title>
1146 <para>An [RoutingPolicyRule] section accepts the following settings. Specify several
1147 [RoutingPolicyRule] sections to configure several rules.
</para>
1149 <variablelist class='network-directives'
>
1151 <term><varname>TypeOfService=
</varname></term>
1153 <para>Takes a number between
0 and
255 that specifies the type of service to match.
</para>
1158 <term><varname>From=
</varname></term>
1160 <para>Specifies the source address prefix to match. Possibly followed by a slash and the
1161 prefix length.
</para>
1166 <term><varname>To=
</varname></term>
1168 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the
1169 prefix length.
</para>
1174 <term><varname>FirewallMark=
</varname></term>
1176 <para>Specifies the iptables firewall mark value to match (a number in the range
1177 1…
4294967295). Optionally, the firewall mask (also a number between
1…
4294967295) can be
1178 suffixed with a slash (
<literal>/
</literal>), e.g.,
<literal>7/
255</literal>.
</para>
1183 <term><varname>Table=
</varname></term>
1185 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes
1186 one of predefined names
<literal>default
</literal>,
<literal>main
</literal>, and
1187 <literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname> in
1188 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1189 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1194 <term><varname>Priority=
</varname></term>
1196 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an integer in the
1197 range
0…
4294967295. Higher number means lower priority, and rules get processed in order of
1198 increasing number. Defaults to unset, and the kernel will pick a value dynamically.
</para>
1203 <term><varname>IncomingInterface=
</varname></term>
1205 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches
1206 packets originating from this host.
</para>
1211 <term><varname>OutgoingInterface=
</varname></term>
1213 <para>Specifies the outgoing device to match. The outgoing interface is only available for
1214 packets originating from local sockets that are bound to a device.
</para>
1219 <term><varname>SourcePort=
</varname></term>
1221 <para>Specifies the source IP port or IP port range match in forwarding information base
1222 (FIB) rules. A port range is specified by the lower and upper port separated by a dash.
1223 Defaults to unset.
</para>
1228 <term><varname>DestinationPort=
</varname></term>
1230 <para>Specifies the destination IP port or IP port range match in forwarding information base
1231 (FIB) rules. A port range is specified by the lower and upper port separated by a dash.
1232 Defaults to unset.
</para>
1237 <term><varname>IPProtocol=
</varname></term>
1239 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP
1240 protocol name such as
<literal>tcp
</literal>,
<literal>udp
</literal> or
1241 <literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
1242 <literal>tcp
</literal> or
<literal>17</literal> for
<literal>udp
</literal>. Defaults to unset.
1248 <term><varname>InvertRule=
</varname></term>
1250 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1255 <term><varname>Family=
</varname></term>
1257 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1258 <literal>both
</literal>. By default, the address family is determined by the address
1259 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1260 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1261 <literal>ipv4
</literal>.
</para>
1266 <term><varname>User=
</varname></term>
1268 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1274 <term><varname>SuppressPrefixLength=
</varname></term>
1276 <para>Takes a number
<replaceable>N
</replaceable> in the range
0…
128 and rejects routing
1277 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1283 <term><varname>SuppressInterfaceGroup=
</varname></term>
1285 <para>Takes an integer in the range
0…
2147483647 and rejects routing decisions that have
1286 an interface with the same group id. It has the same meaning as
1287 <option>suppress_ifgroup
</option> in
<command>ip rule
</command>. Defaults to unset.
</para>
1292 <term><varname>Type=
</varname></term>
1294 <para>Specifies Routing Policy Database (RPDB) rule type. Takes one of
1295 <literal>blackhole
</literal>,
<literal>unreachable
</literal> or
<literal>prohibit
</literal>.
1303 <title>[NextHop] Section Options
</title>
1305 <para>The [NextHop] section is used to manipulate entries in the kernel's
"nexthop" tables. The
1306 [NextHop] section accepts the following settings. Specify several [NextHop] sections to configure
1307 several hops.
</para>
1309 <variablelist class='network-directives'
>
1311 <term><varname>Id=
</varname></term>
1313 <para>The id of the next hop. Takes an integer in the range
1…
4294967295. If unspecified,
1314 then automatically chosen by kernel.
</para>
1319 <term><varname>Gateway=
</varname></term>
1321 <para>As in the [Network] section.
</para>
1326 <term><varname>Family=
</varname></term>
1328 <para>Takes one of the special values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>.
1329 By default, the family is determined by the address specified in
1330 <varname>Gateway=
</varname>. If
<varname>Gateway=
</varname> is not specified, then defaults
1331 to
<literal>ipv4
</literal>.
</para>
1336 <term><varname>OnLink=
</varname></term>
1338 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1339 reachable directly by the current machine (i.e., attached to the local network), so that we
1340 can insert the nexthop in the kernel table without it being complained about. Defaults to
1341 <literal>no
</literal>.
</para>
1346 <term><varname>Blackhole=
</varname></term>
1348 <para>Takes a boolean. If enabled, packets to the corresponding routes are discarded
1349 silently, and
<varname>Gateway=
</varname> cannot be specified. Defaults to
1350 <literal>no
</literal>.
</para>
1355 <term><varname>Group=
</varname></term>
1357 <para>Takes a whitespace separated list of nexthop IDs. Each ID must be in the range
1358 1…
4294967295. Optionally, each nexthop ID can take a weight after a colon
1359 (
<literal><replaceable>id
</replaceable><optional>:
<replaceable>weight
</replaceable></optional></literal>).
1360 The weight must be in the range
1…
255. If the weight is not specified, then it is assumed
1361 that the weight is
1. This setting cannot be specified with
<varname>Gateway=
</varname>,
1362 <varname>Family=
</varname>,
<varname>Blackhole=
</varname>. This setting can be specified
1363 multiple times. If an empty string is assigned, then the all previous assignments are
1364 cleared. Defaults to unset.
</para>
1371 <title>[Route] Section Options
</title>
1373 <para>The [Route] section accepts the following settings. Specify several [Route] sections to
1374 configure several routes.
</para>
1376 <variablelist class='network-directives'
>
1378 <term><varname>Gateway=
</varname></term>
1380 <para>Takes the gateway address or the special values
<literal>_dhcp4
</literal> and
1381 <literal>_ipv6ra
</literal>. If
<literal>_dhcp4
</literal> or
<literal>_ipv6ra
</literal> is
1382 set, then the gateway address provided by DHCPv4 or IPv6 RA is used.
</para>
1387 <term><varname>GatewayOnLink=
</varname></term>
1389 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1390 reachable directly by the current machine (i.e., attached to the local network), so that we
1391 can insert the route in the kernel table without it being complained about. Defaults to
1392 <literal>no
</literal>.
</para>
1397 <term><varname>Destination=
</varname></term>
1399 <para>The destination prefix of the route. Possibly followed by a slash and the prefix
1400 length. If omitted, a full-length host route is assumed.
</para>
1405 <term><varname>Source=
</varname></term>
1407 <para>The source prefix of the route. Possibly followed by a slash and the prefix length. If
1408 omitted, a full-length host route is assumed.
</para>
1413 <term><varname>Metric=
</varname></term>
1415 <para>The metric of the route. Takes an unsigned integer in the range
0…
4294967295. Defaults
1416 to unset, and the kernel's default will be used.
</para>
1421 <term><varname>IPv6Preference=
</varname></term>
1423 <para>Specifies the route preference as defined in
1424 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink> for Router Discovery
1425 messages. Which can be one of
<literal>low
</literal> the route has a lowest priority,
1426 <literal>medium
</literal> the route has a default priority or
<literal>high
</literal> the
1427 route has a highest priority.
</para>
1432 <term><varname>Scope=
</varname></term>
1434 <para>The scope of the IPv4 route, which can be
<literal>global
</literal>,
1435 <literal>site
</literal>,
<literal>link
</literal>,
<literal>host
</literal>, or
1436 <literal>nowhere
</literal>:
</para>
1439 <para><literal>global
</literal> means the route can reach hosts more than one hop away.
1444 <para><literal>site
</literal> means an interior route in the local autonomous system.
1449 <para><literal>link
</literal> means the route can only reach hosts on the local network
1450 (one hop away).
</para>
1454 <para><literal>host
</literal> means the route will not leave the local machine (used for
1455 internal addresses like
127.0.0.1).
</para>
1459 <para><literal>nowhere
</literal> means the destination doesn't exist.
</para>
1463 <para>For IPv4 route, defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
1464 <literal>local
</literal> or
<literal>nat
</literal>, and
<literal>link
</literal> if
1465 <varname>Type=
</varname> is
<literal>broadcast
</literal>,
<literal>multicast
</literal>,
1466 <literal>anycast
</literal>, or direct
<literal>unicast
</literal> routes. In other cases,
1467 defaults to
<literal>global
</literal>. The value is not used for IPv6.
</para>
1472 <term><varname>PreferredSource=
</varname></term>
1474 <para>The preferred source address of the route. The address must be in the format described
1476 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
1482 <term><varname>Table=
</varname></term>
1484 <para>The table identifier for the route. Takes one of predefined names
1485 <literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>, and names
1486 defined in
<varname>RouteTable=
</varname> in
1487 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1488 or a number between
1 and
4294967295. The table can be retrieved using
1489 <command>ip route show table
<replaceable>num
</replaceable></command>. If unset and
1490 <varname>Type=
</varname> is
<literal>local
</literal>,
<literal>broadcast
</literal>,
1491 <literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1492 In other cases, defaults to
<literal>main
</literal>.
</para>
1497 <term><varname>Protocol=
</varname></term>
1499 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special
1500 values
<literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1501 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1507 <term><varname>Type=
</varname></term>
1509 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1510 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1511 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1512 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1513 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e.
1514 a route indicating the path to take to a destination network address. If
1515 <literal>blackhole
</literal>, packets to the defined route are discarded silently. If
1516 <literal>unreachable
</literal>, packets to the defined route are discarded and the ICMP
1517 message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets to the
1518 defined route are discarded and the ICMP message
"Communication Administratively Prohibited"
1519 is generated. If
<literal>throw
</literal>, route lookup in the current routing table will
1520 fail and the route selection process will return to Routing Policy Database (RPDB). Defaults
1521 to
<literal>unicast
</literal>.
</para>
1526 <term><varname>InitialCongestionWindow=
</varname></term>
1528 <para>The TCP initial congestion window is used during the start of a TCP connection.
1529 During the start of a TCP session, when a client requests a resource, the server's initial
1530 congestion window determines how many packets will be sent during the initial burst of data
1531 without waiting for acknowledgement. Takes a number between
1 and
1023. Note that
100 is
1532 considered an extremely large value for this option. When unset, the kernel's default
1533 (typically
10) will be used.
</para>
1538 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1540 <para>The TCP initial advertised receive window is the amount of receive data (in bytes)
1541 that can initially be buffered at one time on a connection. The sending host can send only
1542 that amount of data before waiting for an acknowledgment and window update from the
1543 receiving host. Takes a number between
1 and
1023. Note that
100 is considered an extremely
1544 large value for this option. When unset, the kernel's default will be used.
</para>
1549 <term><varname>QuickAck=
</varname></term>
1551 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the
1552 kernel's default will be used.
</para>
1557 <term><varname>FastOpenNoCookie=
</varname></term>
1559 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1560 When unset, the kernel's default will be used.
</para>
1565 <term><varname>TTLPropagate=
</varname></term>
1567 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1568 When unset, the kernel's default will be used.
</para>
1573 <term><varname>MTUBytes=
</varname></term>
1575 <para>The maximum transmission unit in bytes to set for the route. The usual suffixes K, M,
1576 G, are supported and are understood to the base of
1024.
</para>
1581 <term><varname>TCPAdvertisedMaximumSegmentSize=
</varname></term>
1583 <para>Specifies the Path MSS (in bytes) hints given on TCP layer. The usual suffixes K, M, G,
1584 are supported and are understood to the base of
1024. An unsigned integer in the range
1585 1…
4294967294. When unset, the kernel's default will be used.
</para>
1590 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1592 <para>Configures multipath route. Multipath routing is the technique of using multiple
1593 alternative paths through a network. Takes gateway address. Optionally, takes a network
1594 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for this
1595 multipath route separated with whitespace. This setting can be specified multiple times. If
1596 an empty string is assigned, then the all previous assignments are cleared.
</para>
1601 <term><varname>NextHop=
</varname></term>
1603 <para>Specifies the nexthop id. Takes an unsigned integer in the range
1…
4294967295. If set,
1604 the corresponding [NextHop] section must be configured. Defaults to unset.
</para>
1611 <title>[DHCPv4] Section Options
</title>
1613 <para>The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the
1614 <varname>DHCP=
</varname> setting described above:
</para>
1616 <variablelist class='network-directives'
>
1618 <!-- DHCP packet contents -->
1621 <term><varname>SendHostname=
</varname></term>
1623 <para>When true (the default), the machine's hostname (or the value specified with
1624 <varname>Hostname=
</varname>, described below) will be sent to the DHCP server. Note that the
1625 hostname must consist only of
7-bit ASCII lower-case characters and no spaces or dots, and be
1626 formatted as a valid DNS domain name. Otherwise, the hostname is not sent even if this option
1632 <term><varname>Hostname=
</varname></term>
1634 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's
1635 hostname. Note that the specified hostname must consist only of
7-bit ASCII lower-case
1636 characters and no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1641 <term><varname>MUDURL=
</varname></term>
1643 <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent
1644 to the DHCPv4 server. Takes a URL of length up to
255 characters. A superficial verification
1645 that the string is a valid URL will be performed. DHCPv4 clients are intended to have at most
1646 one MUD URL associated with them. See
1647 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
</para>
1649 <para>MUD is an embedded software standard defined by the IETF that allows IoT device makers
1650 to advertise device specifications, including the intended communication patterns for their
1651 device when it connects to the network. The network can then use this to author a
1652 context-specific access policy, so the device functions only within those parameters.
</para>
1657 <term><varname>ClientIdentifier=
</varname></term>
1659 <para>The DHCPv4 client identifier to use. Takes one of
<option>mac
</option>,
1660 <option>duid
</option> or
<option>duid-only
</option>. If set to
<option>mac
</option>, the
1661 MAC address of the link is used. If set to
<option>duid
</option>, an RFC4361-compliant Client
1662 ID, which is the combination of IAID and DUID (see below), is used. If set to
1663 <option>duid-only
</option>, only DUID is used, this may not be RFC compliant, but some setups
1664 may require to use this. Defaults to
<option>duid
</option>.
</para>
1669 <term><varname>VendorClassIdentifier=
</varname></term>
1671 <para>The vendor class identifier used to identify vendor type and configuration.
</para>
1676 <term><varname>UserClass=
</varname></term>
1678 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or
1679 applications it represents. The information contained in this option is a string that
1680 represents the user class of which the client is a member. Each class sets an identifying
1681 string of information to be used by the DHCP service to classify clients. Takes a
1682 whitespace-separated list of strings.
</para>
1687 <term><varname>DUIDType=
</varname></term>
1689 <para>Override the global
<varname>DUIDType=
</varname> setting for this network. See
1690 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1691 for a description of possible values.
</para>
1696 <term><varname>DUIDRawData=
</varname></term>
1698 <para>Override the global
<varname>DUIDRawData=
</varname> setting for this network. See
1699 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1700 for a description of possible values.
</para>
1705 <term><varname>IAID=
</varname></term>
1707 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned
1713 <term><varname>Anonymize=
</varname></term>
1715 <para>Takes a boolean. When true, the options sent to the DHCP server will follow the
1716 <ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink> (Anonymity Profiles for
1717 DHCP Clients) to minimize disclosure of identifying information. Defaults to false.
</para>
1719 <para>This option should only be set to true when
<varname>MACAddressPolicy=
</varname> is set
1720 to
<option>random
</option> (see
1721 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
1724 <para>When true,
<varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1725 <varname>VendorClassIdentifier=
</varname>,
<varname>UserClass=
</varname>,
1726 <varname>RequestOptions=
</varname>,
<varname>SendOption=
</varname>,
1727 <varname>SendVendorOption=
</varname>, and
<varname>MUDURL=
</varname> are ignored.
</para>
1729 <para>With this option enabled DHCP requests will mimic those generated by Microsoft
1730 Windows, in order to reduce the ability to fingerprint and recognize installations. This
1731 means DHCP request sizes will grow and lease data will be more comprehensive than normally,
1732 though most of the requested data is not actually used.
</para>
1737 <term><varname>RequestOptions=
</varname></term>
1739 <para>Sets request options to be sent to the server in the DHCPv4 request options list. A
1740 whitespace-separated list of integers in the range
1…
254. Defaults to unset.
</para>
1745 <term><varname>SendOption=
</varname></term>
1747 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data
1748 type and data separated with a colon
1749 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1750 The option number must be an integer in the range
1…
254. The type takes one of
1751 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1752 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1753 string may be escaped using
1754 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1755 escapes
</ulink>. This setting can be specified multiple times. If an empty string is
1756 specified, then all options specified earlier are cleared. Defaults to unset.
</para>
1761 <term><varname>SendVendorOption=
</varname></term>
1763 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data
1764 type and data separated with a colon
1765 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1766 The option number must be an integer in the range
1…
254. The type takes one of
1767 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1768 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1769 string may be escaped using
1770 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1771 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1772 then all options specified earlier are cleared. Defaults to unset.
</para>
1777 <term><varname>IPServiceType=
</varname></term>
1779 <para>Takes one of the special values
<literal>none
</literal>,
<literal>CS6
</literal>, or
1780 <literal>CS4
</literal>. When
<literal>none
</literal> no IP service type is set to the packet
1781 sent from the DHCPv4 client. When
<literal>CS6
</literal> (network control) or
1782 <literal>CS4
</literal> (realtime), the corresponding service type will be set. Defaults to
1783 <literal>CS6
</literal>.
</para>
1787 <!-- How to use the DHCP lease -->
1790 <term><varname>Label=
</varname></term>
1792 <para>Specifies the label for the IPv4 address received from the DHCP server. The label must
1793 be a
7-bit ASCII string with a length of
1…
15 characters. Defaults to unset.
</para>
1798 <term><varname>UseDNS=
</varname></term>
1800 <para>When true (the default), the DNS servers received from the DHCP server will be used.
1803 <para>This corresponds to the
<option>nameserver
</option> option in
1804 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1810 <term><varname>RoutesToDNS=
</varname></term>
1812 <para>When true, the routes to the DNS servers received from the DHCP server will be
1813 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored. Defaults to
1819 <term><varname>UseNTP=
</varname></term>
1821 <para>When true (the default), the NTP servers received from the DHCP server will be used by
1822 <filename>systemd-timesyncd.service
</filename>.
</para>
1827 <term><varname>RoutesToNTP=
</varname></term>
1829 <para>When true, the routes to the NTP servers received from the DHCP server will be
1830 configured. When
<varname>UseNTP=
</varname> is disabled, this setting is ignored. Defaults to
1836 <term><varname>UseSIP=
</varname></term>
1838 <para>When true (the default), the SIP servers received from the DHCP server will be collected
1839 and made available to client programs.
</para>
1844 <term><varname>UseMTU=
</varname></term>
1846 <para>When true, the interface maximum transmission unit from the DHCP server will be used on
1847 the current link. If
<varname>MTUBytes=
</varname> is set, then this setting is ignored.
1848 Defaults to false.
</para>
1850 <para>Note, some drivers will reset the interfaces if the MTU is changed. For such
1851 interfaces, please try to use
<varname>IgnoreCarrierLoss=
</varname> with a short timespan,
1852 e.g.
<literal>3 seconds
</literal>.
</para>
1857 <term><varname>UseHostname=
</varname></term>
1859 <para>When true (the default), the hostname received from the DHCP server will be set as the
1860 transient hostname of the system.
</para>
1865 <term><varname>UseDomains=
</varname></term>
1867 <para>Takes a boolean, or the special value
<option>route
</option>. When true, the domain
1868 name received from the DHCP server will be used as DNS search domain over this link, similar
1869 to the effect of the
<option>Domains=
</option> setting. If set to
<option>route
</option>, the
1870 domain name received from the DHCP server will be used for routing DNS queries only, but not
1871 for searching, similar to the effect of the
<option>Domains=
</option> setting when the
1872 argument is prefixed with
<literal>~
</literal>. Defaults to false.
</para>
1874 <para>It is recommended to enable this option only on trusted networks, as setting this
1875 affects resolution of all hostnames, in particular of single-label names. It is generally
1876 safer to use the supplied domain only as routing domain, rather than as search domain, in
1877 order to not have it affect local resolution of single-label names.
</para>
1879 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
1880 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1886 <term><varname>UseRoutes=
</varname></term>
1888 <para>When true (the default), the static routes will be requested from the DHCP server and
1889 added to the routing table with a metric of
1024, and a scope of
<option>global
</option>,
1890 <option>link
</option> or
<option>host
</option>, depending on the route's destination and
1891 gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the link's
1892 own address, the scope will be set to
<option>host
</option>. Otherwise if the gateway is null
1893 (a direct route), a
<option>link
</option> scope will be used. For anything else, scope
1894 defaults to
<option>global
</option>.
</para>
1899 <term><varname>RouteMetric=
</varname></term>
1901 <para>Set the routing metric for routes specified by the DHCP server (including the prefix
1902 route added for the specified prefix). Takes an unsigned integer in the range
0…
4294967295.
1903 Defaults to
1024.
</para>
1908 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1910 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to
1911 unset). The table can be retrieved using
1912 <command>ip route show table
<replaceable>num
</replaceable></command>.
</para>
1914 <para>When used in combination with
<varname>VRF=
</varname>, the VRF's routing table is
1915 used when this parameter is not specified.
</para>
1920 <term><varname>RouteMTUBytes=
</varname></term>
1922 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further
1928 <term><varname>UseGateway=
</varname></term>
1930 <para>When true, the gateway will be requested from the DHCP server and added to the routing
1931 table with a metric of
1024, and a scope of
<option>link
</option>. When unset, the value
1932 specified with
<varname>UseRoutes=
</varname> is used.
</para>
1937 <term><varname>UseTimezone=
</varname></term>
1938 <listitem><para>When true, the timezone received from the DHCP server will be set as timezone
1939 of the local system. Defaults to false.
</para></listitem>
1943 <term><varname>Use6RD=
</varname></term>
1945 <para>When true, subnets of the received IPv6 prefix are assigned to downstream interfaces
1946 which enables
<varname>DHCPPrefixDelegation=
</varname>. See also
1947 <varname>DHCPPrefixDelegation=
</varname> in the [Network] section, the [DHCPPrefixDelegation]
1948 section, and
<ulink url=
"https://tools.ietf.org/html/rfc5969">RFC
5969</ulink>. Defaults to
1954 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
1956 <para>Allows one to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease
1957 lifetime. Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal>. If
1958 specified, the acquired address never expires. Defaults to unset.
</para>
1962 <!-- How to communicate with the server -->
1965 <term><varname>RequestBroadcast=
</varname></term>
1967 <para>Request the server to use broadcast messages before the IP address has been configured.
1968 This is necessary for devices that cannot receive RAW packets, or that cannot receive packets
1969 at all before an IP address has been configured. On the other hand, this must not be enabled
1970 on networks where broadcasts are filtered out.
</para>
1975 <term><varname>MaxAttempts=
</varname></term>
1977 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
1978 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>. Note that the
1979 time between retries is increased exponentially, up to approximately one per minute, so the
1980 network will not be overloaded even if this number is high. The default is suitable in most
1981 circumstances.
</para>
1986 <term><varname>ListenPort=
</varname></term>
1988 <para>Set the port from which the DHCP client packets originate.
</para>
1993 <term><varname>DenyList=
</varname></term>
1995 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
1996 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are rejected.
1997 Note that if
<varname>AllowList=
</varname> is configured then
<varname>DenyList=
</varname> is
2003 <term><varname>AllowList=
</varname></term>
2005 <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a
2006 prefix length after
<literal>/
</literal>. DHCP offers from servers in the list are accepted.
2012 <term><varname>SendRelease=
</varname></term>
2014 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops. Defaults to
2020 <term><varname>SendDecline=
</varname></term>
2022 <para>A boolean. When true,
<command>systemd-networkd
</command> performs IPv4 Duplicate
2023 Address Detection to the acquired address by the DHCPv4 client. If duplicate is detected,
2024 the DHCPv4 client rejects the address by sending a
<constant>DHCPDECLINE
</constant> packet to
2025 the DHCP server, and tries to obtain an IP address again. See
2026 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5227</ulink>. Defaults to false.
</para>
2033 <title>[DHCPv6] Section Options
</title>
2035 <para>The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the
2036 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
2039 <variablelist class='network-directives'
>
2041 <!-- DHCP packet contents -->
2044 <term><varname>MUDURL=
</varname></term>
2045 <term><varname>IAID=
</varname></term>
2046 <term><varname>DUIDType=
</varname></term>
2047 <term><varname>DUIDRawData=
</varname></term>
2048 <term><varname>RequestOptions=
</varname></term>
2050 <para>As in the [DHCPv4] section.
</para>
2055 <term><varname>SendOption=
</varname></term>
2057 <para>As in the [DHCPv4] section, however because DHCPv6 uses
16-bit fields to store option
2058 numbers, the option number is an integer in the range
1…
65536.
</para>
2063 <term><varname>SendVendorOption=
</varname></term>
2065 <para>Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier,
2066 DHCP option number, data type, and data separated with a colon
2067 (
<literal><replaceable>enterprise identifier
</replaceable>:
<replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2068 Enterprise identifier is an unsigned integer in the range
1…
4294967294. The option number
2069 must be an integer in the range
1…
254. Data type takes one of
<literal>uint8
</literal>,
2070 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
2071 <literal>ipv6address
</literal>, or
<literal>string
</literal>. Special characters in the data
2072 string may be escaped using
2073 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2074 escapes
</ulink>. This setting can be specified multiple times. If an empty string is
2075 specified, then all options specified earlier are cleared. Defaults to unset.
</para>
2080 <term><varname>UserClass=
</varname></term>
2082 <para>A DHCPv6 client can use User Class option to identify the type or category of user or
2083 applications it represents. The information contained in this option is a string that
2084 represents the user class of which the client is a member. Each class sets an identifying
2085 string of information to be used by the DHCP service to classify clients. Special characters
2086 in the data string may be escaped using
2087 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2088 escapes
</ulink>. This setting can be specified multiple times. If an empty string is
2089 specified, then all options specified earlier are cleared. Takes a whitespace-separated list
2090 of strings. Note that currently
<constant>NUL
</constant> bytes are not allowed.
</para>
2095 <term><varname>VendorClass=
</varname></term>
2097 <para>A DHCPv6 client can use VendorClass option to identify the vendor that manufactured the
2098 hardware on which the client is running. The information contained in the data area of this
2099 option is contained in one or more opaque fields that identify details of the hardware
2100 configuration. Takes a whitespace-separated list of strings.
</para>
2105 <term><varname>PrefixDelegationHint=
</varname></term>
2107 <para>Takes an IPv6 address with prefix length in the same format as the
2108 <varname>Address=
</varname> in the [Network] section. The DHCPv6 client will include a prefix
2109 hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range
2110 1…
128. Defaults to unset.
</para>
2114 <!-- How to use the DHCP lease -->
2117 <term><varname>UseAddress=
</varname></term>
2119 <para>When true (the default), the IP addresses provided by the DHCPv6 server will be
2125 <term><varname>UseDelegatedPrefix=
</varname></term>
2127 <para>When true (the default), the client will request the DHCPv6 server to delegate
2128 prefixes. If the server provides prefixes to be delegated, then subnets of the prefixes are
2129 assigned to the interfaces which enables
<varname>DHCPPrefixDelegation=
</varname>.
2130 See also the
<varname>DHCPPrefixDelegation=
</varname> setting in the [Network] section,
2131 settings in the [DHCPPrefixDelegation] section, and
2132 <ulink url=
"https://www.rfc-editor.org/rfc/rfc8415.html#section-6.3">RFC
8415</ulink>.
2138 <term><varname>UseDNS=
</varname></term>
2139 <term><varname>UseNTP=
</varname></term>
2140 <term><varname>UseHostname=
</varname></term>
2141 <term><varname>UseDomains=
</varname></term>
2143 <para>As in the [DHCPv4] section.
</para>
2147 <!-- How to communicate with the server -->
2150 <term><varname>WithoutRA=
</varname></term>
2152 <para>Allows DHCPv6 client to start without router advertisements's managed or other
2153 address configuration flag. Takes one of
<literal>no
</literal>,
<literal>solicit
</literal>
2154 or
<literal>information-request
</literal>. If this is not specified,
2155 <literal>solicit
</literal> is used when
<varname>DHCPPrefixDelegation=
</varname> is enabled
2156 and
<varname>UplinkInterface=:self
</varname> is specified in the [DHCPPrefixDelegation]
2157 section. Otherwise, defaults to
<literal>no
</literal>, and the DHCPv6 client will be started
2158 when an RA is received. See also the
<varname>DHCPv6Client=
</varname> setting in the
2159 [IPv6AcceptRA] section.
</para>
2166 <title>[DHCPPrefixDelegation] Section Options
</title>
2167 <para>The [DHCPPrefixDelegation] section configures subnet prefixes of the delegated prefixes
2168 acquired by a DHCPv6 client, or by a DHCPv4 client through the
6RD option on another interface.
2169 The settings in this section are used only when the
<varname>DHCPPrefixDelegation=
</varname>
2170 setting in the [Network] section is enabled.
</para>
2172 <variablelist class='network-directives'
>
2174 <term><varname>UplinkInterface=
</varname></term>
2176 <para>Specifies the name or the index of the uplink interface, or one of the special values
2177 <literal>:self
</literal> and
<literal>:auto
</literal>. When
<literal>:self
</literal>, the
2178 interface itself is considered the uplink interface, and
2179 <varname>WithoutRA=solicit
</varname> is implied if the setting is not explicitly specified.
2180 When
<literal>:auto
</literal>, the first link which acquired prefixes to be delegated from
2181 the DHCPv6 or DHCPv4 server is selected. Defaults to
<literal>:auto
</literal>.
</para>
2186 <term><varname>SubnetId=
</varname></term>
2188 <para>Configure a specific subnet ID on the interface from a (previously) received prefix
2189 delegation. You can either set
"auto" (the default) or a specific subnet ID (as defined in
2190 <ulink url=
"https://tools.ietf.org/html/rfc4291#section-2.5.4">RFC
4291</ulink>, section
2191 2.5.4), in which case the allowed value is hexadecimal, from
0 to
0x7fffffffffffffff
2197 <term><varname>Announce=
</varname></term>
2199 <para>Takes a boolean. When enabled, and
<varname>IPv6SendRA=
</varname> in [Network] section
2200 is enabled, the delegated prefixes are distributed through the IPv6 Router Advertisement.
2201 This setting will be ignored when the
<varname>DHCPPrefixDelegation=
</varname> setting is
2202 enabled on the upstream interface. Defaults to yes.
</para>
2207 <term><varname>Assign=
</varname></term>
2209 <para>Takes a boolean. Specifies whether to add an address from the delegated prefixes which
2210 are received from the WAN interface by the DHCPv6 Prefix Delegation. When true (on LAN
2211 interfce), the EUI-
64 algorithm will be used by default to form an interface identifier from
2212 the delegated prefixes. See also
<varname>Token=
</varname> setting below. Defaults to yes.
2218 <term><varname>Token=
</varname></term>
2220 <para>Specifies an optional address generation mode for assigning an address in each
2221 delegated prefix. This accepts the same syntax as
<varname>Token=
</varname> in the
2222 [IPv6AcceptRA] section. If
<varname>Assign=
</varname> is set to false, then this setting will
2223 be ignored. Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2228 <term><varname>ManageTemporaryAddress=
</varname></term>
2230 <para>As in the [Address] section, but defaults to true.
</para>
2235 <term><varname>RouteMetric=
</varname></term>
2237 <para>The metric of the route to the delegated prefix subnet. Takes an unsigned integer in
2238 the range
0…
4294967295. When set to
0, the kernel's default value is used. Defaults to
256.
2246 <title>[IPv6AcceptRA] Section Options
</title>
2247 <para>The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled
2248 with the
<varname>IPv6AcceptRA=
</varname> setting described above:
</para>
2250 <variablelist class='network-directives'
>
2252 <term><varname>Token=
</varname></term>
2254 <para>Specifies an optional address generation mode for the Stateless Address
2255 Autoconfiguration (SLAAC). The following values are supported:
</para>
2259 <term><option>eui64
</option></term>
2262 The EUI-
64 algorithm will be used to generate an address for that prefix. Only
2263 supported by Ethernet or InfiniBand interfaces.
2268 <term><option>static:
<replaceable>ADDRESS
</replaceable></option></term>
2271 An IPv6 address must be specified after a colon (
<literal>:
</literal>), and the
2272 lower bits of the supplied address are combined with the upper bits of a prefix
2273 received in a Router Advertisement (RA) message to form a complete address. Note
2274 that if multiple prefixes are received in an RA message, or in multiple RA messages,
2275 addresses will be formed from each of them using the supplied address. This mode
2276 implements SLAAC but uses a static interface identifier instead of an identifier
2277 generated by using the EUI-
64 algorithm. Because the interface identifier is static,
2278 if Duplicate Address Detection detects that the computed address is a duplicate
2279 (in use by another node on the link), then this mode will fail to provide an address
2280 for that prefix. If an IPv6 address without mode is specified, then
2281 <literal>static
</literal> mode is assumed.
2286 <term><option>prefixstable[:
<replaceable>ADDRESS
</replaceable>][,
<replaceable>UUID
</replaceable>]
</option></term>
2289 The algorithm specified in
2290 <ulink url=
"https://tools.ietf.org/html/rfc7217">RFC
7217</ulink> will be used to
2291 generate interface identifiers. This mode can optionally take an IPv6 address
2292 separated with a colon (
<literal>:
</literal>). If an IPv6 address is specified,
2293 then an interface identifier is generated only when a prefix received in an RA
2294 message matches the supplied address.
2297 This mode can also optionally take a non-null UUID in the format which
2298 <function>sd_id128_from_string()
</function> accepts, e.g.
2299 <literal>86b123b969ba4b7eb8b3d8605123525a
</literal> or
2300 <literal>86b123b9-
69ba-
4b7e-b8b3-d8605123525a
</literal>. If a UUID is specified, the
2301 value is used as the secret key to generate interface identifiers. If not specified,
2302 then an application specific ID generated with the system's machine-ID will be used
2303 as the secret key. See
2304 <citerefentry><refentrytitle>sd-id128
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2305 <citerefentry><refentrytitle>sd_id128_from_string
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
2307 <citerefentry><refentrytitle>sd_id128_get_machine
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
2310 Note that the
<literal>prefixstable
</literal> algorithm uses both the interface
2311 name and MAC address as input to the hash to compute the interface identifier, so
2312 if either of those are changed the resulting interface identifier (and address)
2313 will be changed, even if the prefix received in the RA message has not been
2320 <para>If no address generation mode is specified (which is the default), or a received
2321 prefix does not match any of the addresses provided in
<literal>prefixstable
</literal>
2322 mode, then the EUI-
64 algorithm will be used for Ethernet or InfiniBand interfaces,
2323 otherwise
<literal>prefixstable
</literal> will be used to form an interface identifier for
2326 <para>This setting can be specified multiple times. If an empty string is assigned, then
2327 the all previous assignments are cleared.
</para>
2330 <programlisting>Token=eui64
2332 Token=static:::
1a:
2b:
3c:
4d
2334 Token=prefixstable:
2002:da8:
1::
</programlisting></para>
2339 <term><varname>UseDNS=
</varname></term>
2341 <para>When true (the default), the DNS servers received in the Router Advertisement will be used.
</para>
2343 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
2344 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2349 <term><varname>UseDomains=
</varname></term>
2351 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
2352 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
2353 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
2354 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
2355 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
2356 <literal>~
</literal>. Defaults to false.
</para>
2358 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
2359 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
2360 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
2361 single-label names.
</para>
2363 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
2364 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2369 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
2371 <para>The table identifier for the routes received in the Router Advertisement
2372 (a number between
1 and
4294967295, or
0 to unset).
2373 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
2379 <term><varname>RouteMetric=
</varname></term>
2381 <para>Set the routing metric for the routes received in the Router Advertisement. Takes an
2382 unsigned integer in the range
0…
4294967295. Defaults to
1024.
</para>
2387 <term><varname>UseMTU=
</varname></term>
2389 <para>Takes a boolean. When true, the MTU received in the Router Advertisement will be
2390 used. Defaults to true.
</para>
2395 <term><varname>UseGateway=
</varname></term>
2397 <para>When true (the default), the router address will be configured as the default gateway.
2403 <term><varname>UseRoutePrefix=
</varname></term>
2405 <para>When true (the default), the routes corresponding to the route prefixes received in
2406 the Router Advertisement will be configured.
</para>
2411 <term><varname>UseAutonomousPrefix=
</varname></term>
2413 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
2414 precedence over any statically configured ones.
</para>
2419 <term><varname>UseOnLinkPrefix=
</varname></term>
2421 <para>When true (the default), the onlink prefix received in the Router Advertisement will be
2422 used and takes precedence over any statically configured ones.
</para>
2427 <term><varname>RouterDenyList=
</varname></term>
2429 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2430 take a prefix length after
<literal>/
</literal>. Any information advertised by the listed
2431 router is ignored.
</para>
2436 <term><varname>RouterAllowList=
</varname></term>
2438 <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally
2439 take a prefix length after
<literal>/
</literal>. Only information advertised by the listed
2440 router is accepted. Note that if
<varname>RouterAllowList=
</varname> is configured then
2441 <varname>RouterDenyList=
</varname> is ignored.
</para>
2446 <term><varname>PrefixDenyList=
</varname></term>
2448 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2449 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2450 in the list are ignored.
</para>
2455 <term><varname>PrefixAllowList=
</varname></term>
2457 <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its
2458 prefix length after
<literal>/
</literal>. IPv6 prefixes supplied via router advertisements
2459 in the list are allowed. Note that if
<varname>PrefixAllowList=
</varname> is configured
2460 then
<varname>PrefixDenyList=
</varname> is ignored.
</para>
2465 <term><varname>RouteDenyList=
</varname></term>
2467 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2468 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2469 advertisements in the list are ignored.
</para>
2474 <term><varname>RouteAllowList=
</varname></term>
2476 <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take
2477 its prefix length after
<literal>/
</literal>. IPv6 route prefixes supplied via router
2478 advertisements in the list are allowed. Note that if
<varname>RouteAllowList=
</varname> is
2479 configured then
<varname>RouteDenyList=
</varname> is ignored.
</para>
2484 <term><varname>DHCPv6Client=
</varname></term>
2486 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true, the
2487 DHCPv6 client will be started when the RA has the managed or other information flag. If set
2488 to
<literal>always
</literal>, the DHCPv6 client will be started in managed mode when an RA
2489 is received, even if neither managed nor other information flag is set in the RA. This will
2490 be ignored when
<varname>WithoutRA=
</varname> in the [DHCPv6] section is enabled, or
2491 <varname>UplinkInterface=:self
</varname> in the [DHCPPrefixDelegation] section is
2492 specified. Defaults to true.
</para>
2499 <title>[DHCPServer] Section Options
</title>
2500 <para>The [DHCPServer] section contains settings for the DHCP server, if enabled via the
2501 <varname>DHCPServer=
</varname> option described above:
</para>
2503 <variablelist class='network-directives'
>
2506 <term><varname>ServerAddress=
</varname></term>
2507 <listitem><para>Specifies server address for the DHCP server. Takes an IPv4 address with prefix
2508 length, for example
<literal>192.168.0.1/
24</literal>. This setting may be useful when the link on
2509 which the DHCP server is running has multiple static addresses. When unset, one of static addresses
2510 in the link will be automatically selected. Defaults to unset.
</para></listitem>
2514 <term><varname>PoolOffset=
</varname></term>
2515 <term><varname>PoolSize=
</varname></term>
2517 <listitem><para>Configures the pool of addresses to hand out. The pool
2518 is a contiguous sequence of IP addresses in the subnet configured for
2519 the server address, which does not include the subnet nor the broadcast
2520 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
2521 from the start of subnet, or zero to use the default value.
2522 <varname>PoolSize=
</varname> takes the number of IP addresses in the
2523 pool or zero to use the default value. By default, the pool starts at
2524 the first address after the subnet address and takes up the rest of
2525 the subnet, excluding the broadcast address. If the pool includes
2526 the server address (the default), this is reserved and not handed
2527 out to clients.
</para></listitem>
2531 <term><varname>DefaultLeaseTimeSec=
</varname></term>
2532 <term><varname>MaxLeaseTimeSec=
</varname></term>
2534 <listitem><para>Control the default and maximum DHCP lease
2535 time to pass to clients. These settings take time values in seconds or
2536 another common time unit, depending on the suffix. The default
2537 lease time is used for clients that did not ask for a specific
2538 lease time. If a client asks for a lease time longer than the
2539 maximum lease time, it is automatically shortened to the
2540 specified time. The default lease time defaults to
1h, the
2541 maximum lease time to
12h. Shorter lease times are beneficial
2542 if the configuration data in DHCP leases changes frequently
2543 and clients shall learn the new settings with shorter
2544 latencies. Longer lease times reduce the generated DHCP
2545 network traffic.
</para></listitem>
2549 <term><varname>UplinkInterface=
</varname></term>
2550 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2551 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS, NTP, or SIP
2552 servers is enabled but no servers are specified, the servers configured in the uplink interface
2553 will be emitted. When
<literal>:auto
</literal>, the link which has a default gateway with the
2554 highest priority will be automatically selected. When
<literal>:none
</literal>, no uplink
2555 interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2559 <term><varname>EmitDNS=
</varname></term>
2560 <term><varname>DNS=
</varname></term>
2562 <listitem><para><varname>EmitDNS=
</varname> takes a boolean. Configures whether the DHCP leases
2563 handed out to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>.
2564 The DNS servers to pass to clients may be configured with the
<varname>DNS=
</varname> option,
2565 which takes a list of IPv4 addresses, or special value
<literal>_server_address
</literal> which
2566 will be converted to the address used by the DHCP server.
</para>
2568 <para>If the
<varname>EmitDNS=
</varname> option is enabled but no servers configured, the
2569 servers are automatically propagated from an
"uplink" interface that has appropriate servers
2570 set. The
"uplink" interface is determined by the default route of the system with the highest
2571 priority. Note that this information is acquired at the time the lease is handed out, and does
2572 not take uplink interfaces into account that acquire DNS server information at a later point.
2573 If no suitable uplink interface is found the DNS server data from
2574 <filename>/etc/resolv.conf
</filename> is used. Also, note that the leases are not refreshed if
2575 the uplink network configuration changes. To ensure clients regularly acquire the most current
2576 uplink DNS server information, it is thus advisable to shorten the DHCP lease time via
2577 <varname>MaxLeaseTimeSec=
</varname> described above.
</para>
2579 <para>This setting can be specified multiple times. If an empty string is specified, then all
2580 DNS servers specified earlier are cleared.
</para></listitem>
2584 <term><varname>EmitNTP=
</varname></term>
2585 <term><varname>NTP=
</varname></term>
2586 <term><varname>EmitSIP=
</varname></term>
2587 <term><varname>SIP=
</varname></term>
2588 <term><varname>EmitPOP3=
</varname></term>
2589 <term><varname>POP3=
</varname></term>
2590 <term><varname>EmitSMTP=
</varname></term>
2591 <term><varname>SMTP=
</varname></term>
2592 <term><varname>EmitLPR=
</varname></term>
2593 <term><varname>LPR=
</varname></term>
2595 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname> settings
2596 described above, these settings configure whether and what server information for the indicate
2597 protocol shall be emitted as part of the DHCP lease. The same syntax, propagation semantics and
2598 defaults apply as for
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname>.
</para></listitem>
2602 <term><varname>EmitRouter=
</varname></term>
2603 <term><varname>Router=
</varname></term>
2605 <listitem><para>The
<varname>EmitRouter=
</varname> setting takes a boolean value, and configures
2606 whether the DHCP lease should contain the router option. The
<varname>Router=
</varname> setting
2607 takes an IPv4 address, and configures the router address to be emitted. When the
2608 <varname>Router=
</varname> setting is not specified, then the server address will be used for
2609 the router option. When the
<varname>EmitRouter=
</varname> setting is disabled, the
2610 <varname>Router=
</varname> setting will be ignored. The
<varname>EmitRouter=
</varname> setting
2611 defaults to true, and the
<varname>Router=
</varname> setting defaults to unset.
2616 <term><varname>EmitTimezone=
</varname></term>
2617 <term><varname>Timezone=
</varname></term>
2619 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2620 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2621 <varname>Timezone=
</varname> setting takes a timezone string
2622 (such as
<literal>Europe/Berlin
</literal> or
2623 <literal>UTC
</literal>) to pass to clients. If no explicit
2624 timezone is set, the system timezone of the local host is
2625 propagated, as determined by the
2626 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2630 <term><varname>NextServer=
</varname></term>
2633 <para>Takes an IPv4 address. Configures the next server used by e.g. PXE boot systems.
2634 Defaults to unset.
</para>
2639 <term><varname>Filename=
</varname></term>
2642 <para>Takes a path or url to a file loaded by e.g. a PXE boot loader. Defaults to unset.
</para>
2647 <term><varname>SendOption=
</varname></term>
2649 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2650 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2651 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2652 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2653 <literal>string
</literal>. Special characters in the data string may be escaped using
2654 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2655 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2656 then all options specified earlier are cleared. Defaults to unset.
</para>
2661 <term><varname>SendVendorOption=
</varname></term>
2663 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2664 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2665 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2666 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2667 <literal>string
</literal>. Special characters in the data string may be escaped using
2668 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2669 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2670 then all options specified earlier are cleared. Defaults to unset.
</para>
2674 <term><varname>BindToInterface=
</varname></term>
2676 <para>Takes a boolean value. When
<literal>yes
</literal>, DHCP server socket will be bound
2677 to its network interface and all socket communication will be restricted to this interface.
2678 Defaults to
<literal>yes
</literal>, except if
<varname>RelayTarget=
</varname> is used (see below),
2679 in which case it defaults to
<literal>no
</literal>.
</para>
2683 <term><varname>RelayTarget=
</varname></term>
2685 <para>Takes an IPv4 address, which must be in the format described in
2686 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
2687 Turns this DHCP server into a DHCP relay agent. See
<ulink url=
"https://tools.ietf.org/html/rfc1542">RFC
1542</ulink>.
2688 The address is the address of DHCP server or another relay agent to forward DHCP messages to and from.
</para>
2692 <term><varname>RelayAgentCircuitId=
</varname></term>
2694 <para>Specifies value for Agent Circuit ID suboption of Relay Agent Information option.
2695 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2696 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2697 Defaults to unset (means no Agent Circuit ID suboption is generated).
2698 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2702 <term><varname>RelayAgentRemoteId=
</varname></term>
2704 <para>Specifies value for Agent Remote ID suboption of Relay Agent Information option.
2705 Takes a string, which must be in the format
<literal>string:
<replaceable>value
</replaceable></literal>,
2706 where
<literal><replaceable>value
</replaceable></literal> should be replaced with the value of the suboption.
2707 Defaults to unset (means no Agent Remote ID suboption is generated).
2708 Ignored if
<varname>RelayTarget=
</varname> is not specified.
</para>
2716 <title>[DHCPServerStaticLease] Section Options
</title>
2717 <para>The
<literal>[DHCPServerStaticLease]
</literal> section configures a static DHCP lease to assign a
2718 fixed IPv4 address to a specific device based on its MAC address. This section can be specified multiple
2721 <variablelist class='network-directives'
>
2723 <term><varname>MACAddress=
</varname></term>
2725 <listitem><para>The hardware address of a device to match. This key is mandatory.
</para></listitem>
2729 <term><varname>Address=
</varname></term>
2731 <listitem><para>The IPv4 address that should be assigned to the device that was matched with
2732 <varname>MACAddress=
</varname>. This key is mandatory.
</para></listitem>
2738 <title>[IPv6SendRA] Section Options
</title>
2739 <para>The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether
2740 to act as a router, if enabled via the
<varname>IPv6SendRA=
</varname> option described above. IPv6
2741 network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections.
2744 <variablelist class='network-directives'
>
2747 <term><varname>Managed=
</varname></term>
2748 <term><varname>OtherInformation=
</varname></term>
2750 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2751 addresses on the network link when
<varname>Managed=
</varname>
2752 is set to
<literal>true
</literal> or if only additional network
2753 information can be obtained via DHCPv6 for the network link when
2754 <varname>OtherInformation=
</varname> is set to
2755 <literal>true
</literal>. Both settings default to
2756 <literal>false
</literal>, which means that a DHCPv6 server is not being
2757 used.
</para></listitem>
2761 <term><varname>RouterLifetimeSec=
</varname></term>
2763 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. The value must be
0
2764 seconds, or between
4 seconds and
9000 seconds. When set to
0, the host is not acting as a router.
2765 Defaults to
1800 seconds (
30 minutes).
</para>
2770 <term><varname>RouterPreference=
</varname></term>
2772 <listitem><para>Configures IPv6 router preference if
2773 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2774 <literal>high
</literal>,
<literal>medium
</literal> and
2775 <literal>low
</literal>, with
<literal>normal
</literal> and
2776 <literal>default
</literal> added as synonyms for
2777 <literal>medium
</literal> just to make configuration easier. See
2778 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2779 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2783 <term><varname>UplinkInterface=
</varname></term>
2784 <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
2785 values
<literal>:none
</literal> and
<literal>:auto
</literal>. When emitting DNS servers or
2786 search domains is enabled but no servers are specified, the servers configured in the uplink
2787 interface will be emitted. When
<literal>:auto
</literal>, the value specified to the same
2788 setting in the [DHCPPrefixDelegation] section will be used if
2789 <varname>DHCPPrefixDelegation=
</varname> is enabled, otherwise the link which has a default
2790 gateway with the highest priority will be automatically selected. When
<literal>:none
</literal>,
2791 no uplink interface will be selected. Defaults to
<literal>:auto
</literal>.
</para></listitem>
2795 <term><varname>EmitDNS=
</varname></term>
2796 <term><varname>DNS=
</varname></term>
2798 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses
2799 that are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is true.
2800 <varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that case
2801 the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS servers are
2802 read from the [Network] section. If the [Network] section does not contain any DNS servers
2803 either, DNS servers from the uplink interface specified in
<varname>UplinkInterface=
</varname>
2804 will be used. When
<varname>EmitDNS=
</varname> is false, no DNS server information is sent in
2805 Router Advertisement messages.
<varname>EmitDNS=
</varname> defaults to true.
</para></listitem>
2809 <term><varname>EmitDomains=
</varname></term>
2810 <term><varname>Domains=
</varname></term>
2812 <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when
2813 <varname>EmitDomains=
</varname> is true. If
<varname>Domains=
</varname> is empty, DNS search
2814 domains are read from the [Network] section. If the [Network] section does not contain any DNS
2815 search domains either, DNS search domains from the uplink interface specified in
2816 <varname>UplinkInterface=
</varname> will be used. When
<varname>EmitDomains=
</varname> is false,
2817 no DNS search domain information is sent in Router Advertisement messages.
2818 <varname>EmitDomains=
</varname> defaults to true.
</para></listitem>
2822 <term><varname>DNSLifetimeSec=
</varname></term>
2824 <listitem><para>Lifetime in seconds for the DNS server addresses listed in
2825 <varname>DNS=
</varname> and search domains listed in
<varname>Domains=
</varname>. Defaults to
2826 3600 seconds (one hour).
</para></listitem>
2833 <title>[IPv6Prefix] Section Options
</title>
2834 <para>One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router
2835 Advertisements. See
<ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink> for further
2838 <variablelist class='network-directives'
>
2841 <term><varname>AddressAutoconfiguration=
</varname></term>
2842 <term><varname>OnLink=
</varname></term>
2844 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2845 autoconfigured with this prefix and whether the prefix can be used for
2846 onlink determination. Both settings default to
<literal>true
</literal>
2847 in order to ease configuration.
2852 <term><varname>Prefix=
</varname></term>
2854 <listitem><para>The IPv6 prefix that is to be distributed to hosts. Similarly to configuring static
2855 IPv6 addresses, the setting is configured as an IPv6 prefix and its prefix length, separated by a
2856 <literal>/
</literal> character. Use multiple [IPv6Prefix] sections to configure multiple IPv6
2857 prefixes since prefix lifetimes, address autoconfiguration and onlink status may differ from one
2858 prefix to another.
</para></listitem>
2862 <term><varname>PreferredLifetimeSec=
</varname></term>
2863 <term><varname>ValidLifetimeSec=
</varname></term>
2865 <listitem><para>Preferred and valid lifetimes for the prefix measured in seconds.
2866 <varname>PreferredLifetimeSec=
</varname> defaults to
1800 seconds (
30 minutes) and
2867 <varname>ValidLifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2871 <term><varname>Assign=
</varname></term>
2872 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2877 <term><varname>Token=
</varname></term>
2879 <para>Specifies an optional address generation mode for assigning an address in each
2880 prefix. This accepts the same syntax as
<varname>Token=
</varname> in the [IPv6AcceptRA]
2881 section. If
<varname>Assign=
</varname> is set to false, then this setting will be ignored.
2882 Defaults to unset, which means the EUI-
64 algorithm will be used.
</para>
2887 <term><varname>RouteMetric=
</varname></term>
2889 <para>The metric of the prefix route. Takes an unsigned integer in the range
0…
4294967295.
2890 When unset or set to
0, the kernel's default value is used. This setting is ignored when
2891 <varname>Assign=
</varname> is false.
</para>
2898 <title>[IPv6RoutePrefix] Section Options
</title>
2899 <para>One or more [IPv6RoutePrefix] sections contain the IPv6
2900 prefix routes that are announced via Router Advertisements. See
2901 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2902 for further details.
</para>
2904 <variablelist class='network-directives'
>
2907 <term><varname>Route=
</varname></term>
2909 <listitem><para>The IPv6 route that is to be distributed to hosts. Similarly to configuring static
2910 IPv6 routes, the setting is configured as an IPv6 prefix routes and its prefix route length,
2911 separated by a
<literal>/
</literal> character. Use multiple [IPv6PrefixRoutes] sections to configure
2912 multiple IPv6 prefix routes.
</para></listitem>
2916 <term><varname>LifetimeSec=
</varname></term>
2918 <listitem><para>Lifetime for the route prefix measured in seconds.
2919 <varname>LifetimeSec=
</varname> defaults to
3600 seconds (one hour).
</para></listitem>
2926 <title>[Bridge] Section Options
</title>
2927 <para>The [Bridge] section accepts the following keys:
</para>
2928 <variablelist class='network-directives'
>
2930 <term><varname>UnicastFlood=
</varname></term>
2932 <para>Takes a boolean. Controls whether the bridge should flood
2933 traffic for which an FDB entry is missing and the destination
2934 is unknown through this port. When unset, the kernel's default will be used.
2939 <term><varname>MulticastFlood=
</varname></term>
2941 <para>Takes a boolean. Controls whether the bridge should flood
2942 traffic for which an MDB entry is missing and the destination
2943 is unknown through this port. When unset, the kernel's default will be used.
2948 <term><varname>MulticastToUnicast=
</varname></term>
2950 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
2951 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
2952 When unset, the kernel's default will be used.
2957 <term><varname>NeighborSuppression=
</varname></term>
2959 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
2960 this port. When unset, the kernel's default will be used.
2965 <term><varname>Learning=
</varname></term>
2967 <para>Takes a boolean. Configures whether MAC address learning is enabled for
2968 this port. When unset, the kernel's default will be used.
2973 <term><varname>HairPin=
</varname></term>
2975 <para>Takes a boolean. Configures whether traffic may be sent back out of the port on which it
2976 was received. When this flag is false, then the bridge will not forward traffic back out of the
2977 receiving port. When unset, the kernel's default will be used.
</para>
2981 <term><varname>Isolated=
</varname></term>
2983 <para>Takes a boolean. Configures whether this port is isolated or not. Within a bridge,
2984 isolated ports can only communicate with non-isolated ports. When set to true, this port can only
2985 communicate with other ports whose Isolated setting is false. When set to false, this port
2986 can communicate with any other ports. When unset, the kernel's default will be used.
</para>
2990 <term><varname>UseBPDU=
</varname></term>
2992 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
2993 processed by the bridge port. When unset, the kernel's default will be used.
</para>
2997 <term><varname>FastLeave=
</varname></term>
2999 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
3000 traffic on a port that receives an IGMP Leave message. It is only used with
3001 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
3005 <term><varname>AllowPortToBeRoot=
</varname></term>
3007 <para>Takes a boolean. Configures whether a given port is allowed to
3008 become a root port. Only used when STP is enabled on the bridge.
3009 When unset, the kernel's default will be used.
</para>
3013 <term><varname>ProxyARP=
</varname></term>
3015 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
3016 When unset, the kernel's default will be used.
</para>
3020 <term><varname>ProxyARPWiFi=
</varname></term>
3022 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
3023 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
3024 When unset, the kernel's default will be used.
</para>
3028 <term><varname>MulticastRouter=
</varname></term>
3030 <para>Configures this port for having multicast routers attached. A port with a multicast
3031 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
3032 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
3033 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
3034 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
3035 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
3039 <term><varname>Cost=
</varname></term>
3041 <para>Sets the
"cost" of sending packets of this interface.
3042 Each port in a bridge may have a different speed and the cost
3043 is used to decide which link to use. Faster interfaces
3044 should have lower costs. It is an integer value between
1 and
3049 <term><varname>Priority=
</varname></term>
3051 <para>Sets the
"priority" of sending packets on this interface.
3052 Each port in a bridge may have a different priority which is used
3053 to decide which link to use. Lower value means higher priority.
3054 It is an integer value between
0 to
63. Networkd does not set any
3055 default, meaning the kernel default value of
32 is used.
</para>
3061 <title>[BridgeFDB] Section Options
</title>
3062 <para>The [BridgeFDB] section manages the forwarding database table of a port and accepts the following
3063 keys. Specify several [BridgeFDB] sections to configure several static MAC table entries.
</para>
3065 <variablelist class='network-directives'
>
3067 <term><varname>MACAddress=
</varname></term>
3069 <para>As in the [Network] section. This key is mandatory.
</para>
3073 <term><varname>Destination=
</varname></term>
3075 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
3079 <term><varname>VLANId=
</varname></term>
3081 <para>The VLAN ID for the new static MAC table entry. If
3082 omitted, no VLAN ID information is appended to the new static MAC
3087 <term><varname>VNI=
</varname></term>
3089 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
3090 the remote VXLAN tunnel endpoint. Takes a number in the range
1…
16777215.
3091 Defaults to unset.
</para>
3095 <term><varname>AssociatedWith=
</varname></term>
3097 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
3098 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
3099 <literal>use
</literal> means the address is in use. User space can use this option to
3100 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
3101 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
3102 means the address is associated with master devices fdb.
<literal>router
</literal> means
3103 the destination address is associated with a router. Note that it's valid if the referenced
3104 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
3108 <term><varname>OutgoingInterface=
</varname></term>
3110 <para>Specifies the name or index of the outgoing interface for the VXLAN device driver to
3111 reach the remote VXLAN tunnel endpoint. Defaults to unset.
</para>
3117 <title>[BridgeMDB] Section Options
</title>
3118 <para>The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following
3119 keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.
</para>
3121 <variablelist class='network-directives'
>
3123 <term><varname>MulticastGroupAddress=
</varname></term>
3125 <para>Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.
</para>
3129 <term><varname>VLANId=
</varname></term>
3131 <para>The VLAN ID for the new entry. Valid ranges are
0 (no VLAN) to
4094. Optional, defaults to
0.
</para>
3138 <title>[LLDP] Section Options
</title>
3139 <para>The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following
3141 <variablelist class='network-directives'
>
3143 <term><varname>MUDURL=
</varname></term>
3145 <para>When configured, the specified Manufacturer Usage Descriptions (MUD) URL will be sent in
3146 LLDP packets. The syntax and semantics are the same as for
<varname>MUDURL=
</varname> in the
3147 [DHCPv4] section described above.
</para>
3149 <para>The MUD URLs received via LLDP packets are saved and can be read using the
3150 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
3157 <title>[CAN] Section Options
</title>
3158 <para>The [CAN] section manages the Controller Area Network (CAN bus) and accepts the
3159 following keys:
</para>
3160 <variablelist class='network-directives'
>
3162 <term><varname>BitRate=
</varname></term>
3164 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
3165 be used here. Takes a number in the range
1…
4294967295.
</para>
3169 <term><varname>SamplePoint=
</varname></term>
3171 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
3172 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>). This will be ignored when
3173 <varname>BitRate=
</varname> is unspecified.
</para>
3177 <term><varname>TimeQuantaNSec=
</varname></term>
3178 <term><varname>PropagationSegment=
</varname></term>
3179 <term><varname>PhaseBufferSegment1=
</varname></term>
3180 <term><varname>PhaseBufferSegment2=
</varname></term>
3181 <term><varname>SyncJumpWidth=
</varname></term>
3183 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3184 synchronization jump width, which allow one to define the CAN bit-timing in a hardware
3185 independent format as proposed by the Bosch CAN
2.0 Specification.
3186 <varname>TimeQuantaNSec=
</varname> takes a timespan in nanoseconds.
3187 <varname>PropagationSegment=
</varname>,
<varname>PhaseBufferSegment1=
</varname>,
3188 <varname>PhaseBufferSegment2=
</varname>, and
<varname>SyncJumpWidth=
</varname> take number
3189 of time quantum specified in
<varname>TimeQuantaNSec=
</varname> and must be an unsigned
3190 integer in the range
0…
4294967295. These settings except for
3191 <varname>SyncJumpWidth=
</varname> will be ignored when
<varname>BitRate=
</varname> is
3196 <term><varname>DataBitRate=
</varname></term>
3197 <term><varname>DataSamplePoint=
</varname></term>
3199 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
3200 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
3204 <term><varname>DataTimeQuantaNSec=
</varname></term>
3205 <term><varname>DataPropagationSegment=
</varname></term>
3206 <term><varname>DataPhaseBufferSegment1=
</varname></term>
3207 <term><varname>DataPhaseBufferSegment2=
</varname></term>
3208 <term><varname>DataSyncJumpWidth=
</varname></term>
3210 <para>Specifies the time quanta, propagation segment, phase buffer segment
1 and
2, and the
3211 synchronization jump width for the data phase, if CAN-FD is used. These settings are
3212 analogous to the
<varname>TimeQuantaNSec=
</varname> or related settings.
</para>
3216 <term><varname>FDMode=
</varname></term>
3218 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
3219 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
3220 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys, or
3221 <varname>DataTimeQuanta=
</varname> and related settings.
</para>
3225 <term><varname>FDNonISO=
</varname></term>
3227 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
3228 interface. When unset, the kernel's default will be used.
</para>
3232 <term><varname>RestartSec=
</varname></term>
3234 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
3235 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
3236 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
3237 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
3238 automatic restart off. By default automatic restart is disabled.
</para>
3242 <term><varname>Termination=
</varname></term>
3244 <para>Takes a boolean or a termination resistor value in ohm in the range
0…
65535. When
3245 <literal>yes
</literal>, the termination resistor is set to
120 ohm. When
3246 <literal>no
</literal> or
<literal>0</literal> is set, the termination resistor is disabled.
3247 When unset, the kernel's default will be used.
</para>
3251 <term><varname>TripleSampling=
</varname></term>
3253 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
3254 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
3258 <term><varname>BusErrorReporting=
</varname></term>
3260 <para>Takes a boolean. When
<literal>yes
</literal>, reporting of CAN bus errors is activated
3261 (those include single bit, frame format, and bit stuffing errors, unable to send dominant bit,
3262 unable to send recessive bit, bus overload, active error announcement, error occurred on
3263 transmission). When unset, the kernel's default will be used. Note: in case of a CAN bus with a
3264 single CAN device, sending a CAN frame may result in a huge number of CAN bus errors.
</para>
3268 <term><varname>ListenOnly=
</varname></term>
3270 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
3271 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
3272 bit. Listen-only mode is important to debug CAN networks without interfering with the
3273 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
3278 <term><varname>Loopback=
</varname></term>
3280 <para>Takes a boolean. When
<literal>yes
</literal>, loopback mode is enabled. When the
3281 loopback mode is enabled, the interface treats messages transmitted by itself as received
3282 messages. The loopback mode is important to debug CAN networks. When unset, the kernel's
3283 default will be used.
</para>
3287 <term><varname>OneShot=
</varname></term>
3289 <para>Takes a boolean. When
<literal>yes
</literal>, one-shot mode is enabled. When unset,
3290 the kernel's default will be used.
</para>
3294 <term><varname>PresumeAck=
</varname></term>
3296 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will ignore missing CAN
3297 ACKs. When unset, the kernel's default will be used.
</para>
3301 <term><varname>ClassicDataLengthCode=
</varname></term>
3303 <para>Takes a boolean. When
<literal>yes
</literal>, the interface will handle the
4bit data
3304 length code (DLC). When unset, the kernel's default will be used.
</para>
3311 <title>[IPoIB] Section Options
</title>
3312 <para>The [IPoIB] section manages the IP over Infiniband and accepts the following keys:
</para>
3313 <variablelist class='network-directives'
>
3314 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_mode" />
3315 <xi:include href=
"systemd.netdev.xml" xpointer=
"ipoib_umcast" />
3320 <title>[QDisc] Section Options
</title>
3321 <para>The [QDisc] section manages the traffic control queueing discipline (qdisc).
</para>
3323 <variablelist class='network-directives'
>
3325 <term><varname>Parent=
</varname></term>
3327 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
3328 or
<literal>ingress
</literal>. This is mandatory.
</para>
3332 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3337 <title>[NetworkEmulator] Section Options
</title>
3338 <para>The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It
3339 can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP
3340 applications, or limit the bandwidth usage of a particular service to simulate internet connections.
3343 <variablelist class='network-directives'
>
3344 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3345 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3348 <term><varname>DelaySec=
</varname></term>
3350 <para>Specifies the fixed amount of delay to be added to all packets going out of the
3351 interface. Defaults to unset.
</para>
3356 <term><varname>DelayJitterSec=
</varname></term>
3358 <para>Specifies the chosen delay to be added to the packets outgoing to the network
3359 interface. Defaults to unset.
</para>
3364 <term><varname>PacketLimit=
</varname></term>
3366 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
3367 An unsigned integer in the range
0…
4294967294. Defaults to
1000.
</para>
3372 <term><varname>LossRate=
</varname></term>
3374 <para>Specifies an independent loss probability to be added to the packets outgoing from the
3375 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3380 <term><varname>DuplicateRate=
</varname></term>
3382 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
3383 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
3390 <title>[TokenBucketFilter] Section Options
</title>
3391 <para>The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter
3394 <variablelist class='network-directives'
>
3395 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3396 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3399 <term><varname>LatencySec=
</varname></term>
3401 <para>Specifies the latency parameter, which specifies the maximum amount of time a
3402 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
3407 <term><varname>LimitBytes=
</varname></term>
3409 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
3410 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
3411 respectively, to the base of
1024. Defaults to unset.
</para>
3416 <term><varname>BurstBytes=
</varname></term>
3418 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
3419 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
3420 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to
3426 <term><varname>Rate=
</varname></term>
3428 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
3429 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
3430 Defaults to unset.
</para>
3435 <term><varname>MPUBytes=
</varname></term>
3437 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
3438 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3439 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to zero.
</para>
3444 <term><varname>PeakRate=
</varname></term>
3446 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
3447 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3448 1000. Defaults to unset.
</para>
3453 <term><varname>MTUBytes=
</varname></term>
3455 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
3456 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
3457 Defaults to unset.
</para>
3464 <title>[PIE] Section Options
</title>
3465 <para>The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral
3466 controller-Enhanced (PIE).
</para>
3468 <variablelist class='network-directives'
>
3469 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3470 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3473 <term><varname>PacketLimit=
</varname></term>
3475 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3476 incoming packets are dropped. An unsigned integer in the range
1…
4294967294. Defaults to unset and
3477 kernel's default is used.
</para>
3484 <title>[FlowQueuePIE] Section Options
</title>
3485 <para>The
<literal>[FlowQueuePIE]
</literal> section manages the queueing discipline
3486 (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).
</para>
3488 <variablelist class='network-directives'
>
3489 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3490 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3493 <term><varname>PacketLimit=
</varname></term>
3495 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3496 incoming packets are dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and
3497 kernel's default is used.
</para>
3504 <title>[StochasticFairBlue] Section Options
</title>
3505 <para>The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue
3508 <variablelist class='network-directives'
>
3509 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3510 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3513 <term><varname>PacketLimit=
</varname></term>
3515 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3516 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3517 kernel's default is used.
</para>
3524 <title>[StochasticFairnessQueueing] Section Options
</title>
3525 <para>The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic
3526 fairness queueing (sfq).
</para>
3528 <variablelist class='network-directives'
>
3529 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3530 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3533 <term><varname>PerturbPeriodSec=
</varname></term>
3535 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
3542 <title>[BFIFO] Section Options
</title>
3543 <para>The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First
3546 <variablelist class='network-directives'
>
3547 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3548 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3551 <term><varname>LimitBytes=
</varname></term>
3553 <para>Specifies the hard limit in bytes on the FIFO buffer size. The size limit prevents overflow
3554 in case the kernel is unable to dequeue packets as quickly as it receives them. When this limit is
3555 reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed
3556 as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3557 kernel default is used.
</para>
3564 <title>[PFIFO] Section Options
</title>
3565 <para>The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out
3568 <variablelist class='network-directives'
>
3569 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3570 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3573 <term><varname>PacketLimit=
</varname></term>
3575 <para>Specifies the hard limit on the number of packets in the FIFO queue. The size limit prevents
3576 overflow in case the kernel is unable to dequeue packets as quickly as it receives them. When this
3577 limit is reached, incoming packets are dropped. An unsigned integer in the range
3578 0…
4294967294. Defaults to unset and kernel's default is used.
</para>
3585 <title>[PFIFOHeadDrop] Section Options
</title>
3586 <para>The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out
3587 Head Drop (pfifo_head_drop).
</para>
3589 <variablelist class='network-directives'
>
3590 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3591 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3594 <term><varname>PacketLimit=
</varname></term>
3596 <para>As in [PFIFO] section.
</para></listitem>
3602 <title>[PFIFOFast] Section Options
</title>
3603 <para>The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast
3604 (pfifo_fast).
</para>
3606 <variablelist class='network-directives'
>
3607 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3608 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3613 <title>[CAKE] Section Options
</title>
3614 <para>The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced
3617 <variablelist class='network-directives'
>
3618 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3619 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3622 <term><varname>Bandwidth=
</varname></term>
3624 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
3625 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
3626 unset and kernel's default is used.
</para>
3631 <term><varname>AutoRateIngress=
</varname></term>
3633 <para>Takes a boolean value. Enables automatic capacity estimation based on traffic arriving
3634 at this qdisc. This is most likely to be useful with cellular links, which tend to change
3635 quality randomly. If this setting is enabled, the
<varname>Bandwidth=
</varname> setting is
3636 used as an initial estimate. Defaults to unset, and the kernel's default is used.
</para>
3641 <term><varname>OverheadBytes=
</varname></term>
3643 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative.
3644 Takes an integer in the range -
64…
256. Defaults to unset and kernel's default is used.
3650 <term><varname>MPUBytes=
</varname></term>
3652 <para>Rounds each packet (including overhead) up to the specified bytes. Takes an integer in
3653 the range
1…
256. Defaults to unset and kernel's default is used.
</para>
3658 <term><varname>CompensationMode=
</varname></term>
3660 <para>Takes one of
<literal>none
</literal>,
<literal>atm
</literal>, or
<literal>ptm
</literal>.
3661 Specifies the compensation mode for overhead calculation. When
<literal>none
</literal>, no
3662 compensation is taken into account. When
<literal>atm
</literal>, enables the compensation for
3663 ATM cell framing, which is normally found on ADSL links. When
<literal>ptm
</literal>, enables
3664 the compensation for PTM encoding, which is normally found on VDSL2 links and uses a
64b/
65b
3665 encoding scheme. Defaults to unset and the kernel's default is used.
</para>
3670 <term><varname>UseRawPacketSize=
</varname></term>
3672 <para>Takes a boolean value. When true, the packet size reported by the Linux kernel will be
3673 used, instead of the underlying IP packet size. Defaults to unset, and the kernel's default
3679 <term><varname>FlowIsolationMode=
</varname></term>
3681 <para>CAKE places packets from different flows into different queues, then packets from each
3682 queue are delivered fairly. This specifies whether the fairness is based on source address,
3683 destination address, individual flows, or any combination of those. The available values are:
3688 <term><option>none
</option></term>
3690 The flow isolation is disabled, and all traffic passes through a single queue.
3694 <term><option>src-host
</option></term>
3696 Flows are defined only by source address. Equivalent to the
<literal>srchost
</literal>
3697 option for
<command>tc qdisc
</command> command. See also
3698 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3702 <term><option>dst-host
</option></term>
3704 Flows are defined only by destination address. Equivalent to the
3705 <literal>dsthost
</literal> option for
<command>tc qdisc
</command> command. See also
3706 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3710 <term><option>hosts
</option></term>
3712 Flows are defined by source-destination host pairs. Equivalent to the same option for
3713 <command>tc qdisc
</command> command. See also
3714 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3718 <term><option>flows
</option></term>
3720 Flows are defined by the entire
5-tuple of source address, destination address,
3721 transport protocol, source port and destination port. Equivalent to the same option for
3722 <command>tc qdisc
</command> command. See also
3723 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3727 <term><option>dual-src-host
</option></term>
3729 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3730 fairness is applied first over source addresses, then over individual flows. Equivalent
3731 to the
<literal>dual-srchost
</literal> option for
<command>tc qdisc
</command> command.
3733 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3737 <term><option>dual-dst-host
</option></term>
3739 Flows are defined by the
5-tuple (see
<literal>flows
</literal> in the above), and
3740 fairness is applied first over destination addresses, then over individual flows.
3741 Equivalent to the
<literal>dual-dsthost
</literal> option for
3742 <command>tc qdisc
</command> command. See also
3743 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3747 <term><option>triple
</option></term>
3749 Flows are defined by the
5-tuple (see
<literal>flows
</literal>), and fairness is
3750 applied over source and destination addresses, and also over individual flows.
3751 Equivalent to the
<literal>triple-isolate
</literal> option for
3752 <command>tc qdisc
</command> command. See also
3753 <citerefentry project='man-pages'
><refentrytitle>tc-cake
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
3758 <para>Defaults to unset and the kernel's default is used.
</para>
3763 <term><varname>NAT=
</varname></term>
3765 <para>Takes a boolean value. When true, CAKE performs a NAT lookup before applying
3766 flow-isolation rules, to determine the true addresses and port numbers of the packet, to
3767 improve fairness between hosts inside the NAT. This has no practical effect when
3768 <varname>FlowIsolationMode=
</varname> is
<literal>none
</literal> or
<literal>flows
</literal>,
3769 or if NAT is performed on a different host. Defaults to unset, and the kernel's default is
3775 <term><varname>PriorityQueueingPreset=
</varname></term>
3777 <para>CAKE divides traffic into
<literal>tins
</literal>, and each tin has its own independent
3778 set of flow-isolation queues, bandwidth threshold, and priority. This specifies the preset of
3779 tin profiles. The available values are:
</para>
3783 <term><option>besteffort
</option></term>
3785 Disables priority queueing by placing all traffic in one tin.
3789 <term><option>precedence
</option></term>
3791 Enables priority queueing based on the legacy interpretation of TOS
3792 <literal>Precedence
</literal> field. Use of this preset on the modern Internet is
3797 <term><option>diffserv8
</option></term>
3799 Enables priority queueing based on the Differentiated Service
3800 (
<literal>DiffServ
</literal>) field with eight tins: Background Traffic, High
3801 Throughput, Best Effort, Video Streaming, Low Latency Transactions, Interactive Shell,
3802 Minimum Latency, and Network Control.
3806 <term><option>diffserv4
</option></term>
3808 Enables priority queueing based on the Differentiated Service
3809 (
<literal>DiffServ
</literal>) field with four tins: Background Traffic, Best Effort,
3810 Streaming Media, and Latency Sensitive.
3814 <term><option>diffserv3
</option></term>
3816 Enables priority queueing based on the Differentiated Service
3817 (
<literal>DiffServ
</literal>) field with three tins: Background Traffic, Best Effort,
3818 and Latency Sensitive.
3823 <para>Defaults to unset, and the kernel's default is used.
</para>
3828 <term><varname>FirewallMark=
</varname></term>
3830 <para>Takes an integer in the range
1…
4294967295. When specified, firewall-mark-based
3831 overriding of CAKE's tin selection is enabled. Defaults to unset, and the kernel's default is
3837 <term><varname>Wash=
</varname></term>
3839 <para>Takes a boolean value. When true, CAKE clears the DSCP fields, except for ECN bits, of
3840 any packet passing through CAKE. Defaults to unset, and the kernel's default is used.
</para>
3845 <term><varname>SplitGSO=
</varname></term>
3847 <para>Takes a boolean value. When true, CAKE will split General Segmentation Offload (GSO)
3848 super-packets into their on-the-wire components and dequeue them individually. Defaults to
3849 unset, and the kernel's default is used.
</para>
3857 <title>[ControlledDelay] Section Options
</title>
3858 <para>The [ControlledDelay] section manages the queueing discipline (qdisc) of
3859 controlled delay (CoDel).
</para>
3861 <variablelist class='network-directives'
>
3862 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3863 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3866 <term><varname>PacketLimit=
</varname></term>
3868 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3869 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
3870 kernel's default is used.
</para>
3875 <term><varname>TargetSec=
</varname></term>
3877 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3878 Defaults to unset and kernel's default is used.
</para>
3883 <term><varname>IntervalSec=
</varname></term>
3885 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3886 become too stale. Defaults to unset and kernel's default is used.
</para>
3891 <term><varname>ECN=
</varname></term>
3893 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3894 unset and kernel's default is used.
</para>
3899 <term><varname>CEThresholdSec=
</varname></term>
3901 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3902 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3909 <title>[DeficitRoundRobinScheduler] Section Options
</title>
3910 <para>The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round
3911 Robin Scheduler (DRR).
</para>
3913 <variablelist class='network-directives'
>
3914 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3915 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3920 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
3921 <para>The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round
3922 Robin Scheduler (DRR).
</para>
3924 <variablelist class='network-directives'
>
3925 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3926 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3929 <term><varname>QuantumBytes=
</varname></term>
3931 <para>Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves
3932 to the next class. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3933 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to the MTU of the
3942 <title>[EnhancedTransmissionSelection] Section Options
</title>
3943 <para>The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced
3944 Transmission Selection (ETS).
</para>
3946 <variablelist class='network-directives'
>
3947 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3948 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3951 <term><varname>Bands=
</varname></term>
3953 <para>Specifies the number of bands. An unsigned integer in the range
1…
16. This value has to be at
3954 least large enough to cover the strict bands specified through the
<varname>StrictBands=
</varname>
3955 and bandwidth-sharing bands specified in
<varname>QuantumBytes=
</varname>.
</para>
3960 <term><varname>StrictBands=
</varname></term>
3962 <para>Specifies the number of bands that should be created in strict mode. An unsigned integer in
3963 the range
1…
16.
</para>
3968 <term><varname>QuantumBytes=
</varname></term>
3970 <para>Specifies the white-space separated list of quantum used in band-sharing bands. When
3971 suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3972 respectively, to the base of
1024. This setting can be specified multiple times. If an empty
3973 string is assigned, then the all previous assignments are cleared.
</para>
3978 <term><varname>PriorityMap=
</varname></term>
3980 <para>The priority map maps the priority of a packet to a band. The argument is a whitespace
3981 separated list of numbers. The first number indicates which band the packets with priority
0 should
3982 be put to, the second is for priority
1, and so on. There can be up to
16 numbers in the list. If
3983 there are fewer, the default band that traffic with one of the unmentioned priorities goes to is
3984 the last one. Each band number must be in the range
0…
255. This setting can be specified multiple
3985 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
3992 <title>[GenericRandomEarlyDetection] Section Options
</title>
3993 <para>The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random
3994 Early Detection (GRED).
</para>
3996 <variablelist class='network-directives'
>
3997 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3998 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4001 <term><varname>VirtualQueues=
</varname></term>
4003 <para>Specifies the number of virtual queues. Takes an integer in the range
1…
16. Defaults to unset
4004 and kernel's default is used.
</para>
4009 <term><varname>DefaultVirtualQueue=
</varname></term>
4011 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
4012 Defaults to unset and kernel's default is used.
</para>
4017 <term><varname>GenericRIO=
</varname></term>
4019 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
4020 unset and kernel's default is used.
</para>
4027 <title>[FairQueueingControlledDelay] Section Options
</title>
4028 <para>The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing
4029 controlled delay (FQ-CoDel).
</para>
4031 <variablelist class='network-directives'
>
4032 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4033 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4036 <term><varname>PacketLimit=
</varname></term>
4038 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
4039 dropped. Defaults to unset and kernel's default is used.
</para>
4044 <term><varname>MemoryLimitBytes=
</varname></term>
4046 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
4047 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4048 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
4053 <term><varname>Flows=
</varname></term>
4055 <para>Specifies the number of flows into which the incoming packets are classified.
4056 Defaults to unset and kernel's default is used.
</para>
4061 <term><varname>TargetSec=
</varname></term>
4063 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
4064 Defaults to unset and kernel's default is used.
</para>
4069 <term><varname>IntervalSec=
</varname></term>
4071 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
4072 become too stale. Defaults to unset and kernel's default is used.
</para>
4077 <term><varname>QuantumBytes=
</varname></term>
4079 <para>Specifies the number of bytes used as the
"deficit" in the fair queuing algorithm timespan.
4080 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4081 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
4086 <term><varname>ECN=
</varname></term>
4088 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
4089 unset and kernel's default is used.
</para>
4094 <term><varname>CEThresholdSec=
</varname></term>
4096 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4097 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4104 <title>[FairQueueing] Section Options
</title>
4105 <para>The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing
4108 <variablelist class='network-directives'
>
4109 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4110 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4113 <term><varname>PacketLimit=
</varname></term>
4115 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
4116 dropped. Defaults to unset and kernel's default is used.
</para>
4121 <term><varname>FlowLimit=
</varname></term>
4123 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
4124 unset and kernel's default is used.
</para>
4129 <term><varname>QuantumBytes=
</varname></term>
4131 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
4132 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4133 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
4134 default is used.
</para>
4139 <term><varname>InitialQuantumBytes=
</varname></term>
4141 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
4142 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
4143 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
4144 kernel's default is used.
</para>
4149 <term><varname>MaximumRate=
</varname></term>
4151 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
4152 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
4153 1000. Defaults to unset and kernel's default is used.
</para>
4158 <term><varname>Buckets=
</varname></term>
4160 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
4161 kernel's default is used.
</para>
4166 <term><varname>OrphanMask=
</varname></term>
4168 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
4169 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
4170 kernel's default is used.
</para>
4175 <term><varname>Pacing=
</varname></term>
4177 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
4178 default is used.
</para>
4183 <term><varname>CEThresholdSec=
</varname></term>
4185 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
4186 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
4193 <title>[TrivialLinkEqualizer] Section Options
</title>
4194 <para>The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link
4195 equalizer (teql).
</para>
4197 <variablelist class='network-directives'
>
4198 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4199 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4202 <term><varname>Id=
</varname></term>
4204 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
4205 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
4206 <constant>max_equalizers=N+
1</constant> option must be loaded before
4207 <command>systemd-networkd
</command> is started.
</para>
4214 <title>[HierarchyTokenBucket] Section Options
</title>
4215 <para>The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token
4216 bucket (htb).
</para>
4218 <variablelist class='network-directives'
>
4219 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4220 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4223 <term><varname>DefaultClass=
</varname></term>
4225 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
4226 to the class. Defaults to unset.
</para>
4231 <term><varname>RateToQuantum=
</varname></term>
4233 <para>Takes an unsigned integer. The DRR quantums are calculated by dividing the value
4234 configured in
<varname>Rate=
</varname> by
<varname>RateToQuantum=
</varname>.
</para>
4241 <title>[HierarchyTokenBucketClass] Section Options
</title>
4242 <para>The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket
4245 <variablelist class='network-directives'
>
4246 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4247 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4250 <term><varname>Priority=
</varname></term>
4252 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
4253 priority field are tried for packets first.
</para>
4258 <term><varname>QuantumBytes=
</varname></term>
4260 <para>Specifies how many bytes to serve from leaf at once. When suffixed with K, M, or G, the
4261 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4267 <term><varname>MTUBytes=
</varname></term>
4269 <para>Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified
4270 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4275 <term><varname>OverheadBytes=
</varname></term>
4277 <para>Takes an unsigned integer which specifies per-packet size overhead used in rate
4278 computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
4279 Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
4284 <term><varname>Rate=
</varname></term>
4286 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
4287 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
4288 to the base of
1000. This setting is mandatory.
</para>
4293 <term><varname>CeilRate=
</varname></term>
4295 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
4296 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
4297 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
4303 <term><varname>BufferBytes=
</varname></term>
4305 <para>Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed
4306 with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
4307 to the base of
1024.
</para>
4312 <term><varname>CeilBufferBytes=
</varname></term>
4314 <para>Specifies the maximum bytes burst for ceil which can be accumulated during idle period.
4315 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
4316 respectively, to the base of
1024.
</para>
4323 <title>[HeavyHitterFilter] Section Options
</title>
4324 <para>The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter
4327 <variablelist class='network-directives'
>
4328 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4329 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4332 <term><varname>PacketLimit=
</varname></term>
4334 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
4335 incoming packets are dropped. An unsigned integer in the range
0…
4294967294. Defaults to unset and
4336 kernel's default is used.
</para>
4343 <title>[QuickFairQueueing] Section Options
</title>
4344 <para>The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing
4347 <variablelist class='network-directives'
>
4348 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
4349 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
4354 <title>[QuickFairQueueingClass] Section Options
</title>
4355 <para>The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing
4358 <variablelist class='network-directives'
>
4359 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
4360 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
4363 <term><varname>Weight=
</varname></term>
4365 <para>Specifies the weight of the class. Takes an integer in the range
1…
1023. Defaults to
4366 unset in which case the kernel default is used.
</para>
4371 <term><varname>MaxPacketBytes=
</varname></term>
4373 <para>Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the
4374 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
4375 1024. When unset, the kernel default is used.
</para>
4382 <title>[BridgeVLAN] Section Options
</title>
4383 <para>The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the
4384 following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The
4385 <varname>VLANFiltering=
</varname> option has to be enabled, see the [Bridge] section in
4386 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
4388 <variablelist class='network-directives'
>
4390 <term><varname>VLAN=
</varname></term>
4392 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. Takes
4393 an integer in the range
1…
4094.
</para>
4397 <term><varname>EgressUntagged=
</varname></term>
4399 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
4400 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
4401 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
4405 <term><varname>PVID=
</varname></term>
4407 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
4408 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
4409 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
4416 <title>Examples
</title>
4418 <title>Static network configuration
</title>
4420 <programlisting># /etc/systemd/network/
50-static.network
4425 Address=
192.168.0.15/
24
4426 Gateway=
192.168.0.1</programlisting>
4428 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
4429 specified gateway will be used for a default route.
</para>
4433 <title>DHCP on ethernet links
</title>
4435 <programlisting># /etc/systemd/network/
80-dhcp.network
4440 DHCP=yes
</programlisting>
4442 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
4443 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
4447 <title>IPv6 Prefix Delegation (DHCPv6 PD)
</title>
4449 <programlisting># /etc/systemd/network/
55-dhcpv6-pd-upstream.network
4456 # The below setting is optional, to also assign an address in the delegated prefix
4457 # to the upstream interface. If not necessary, then comment out the line below and
4458 # the [DHCPPrefixDelegation] section.
4459 DHCPPrefixDelegation=yes
4461 # If the upstream network provides Router Advertisement with Managed bit set,
4462 # then comment out the line below and WithoutRA= setting in the [DHCPv6] section.
4468 [DHCPPrefixDelegation]
4469 UplinkInterface=:self
4471 Announce=no
</programlisting>
4473 <programlisting># /etc/systemd/network/
55-dhcpv6-pd-downstream.network
4478 DHCPPrefixDelegation=yes
4481 # It is expected that the host is acting as a router. So, usually it is not
4482 # necessary to receive Router Advertisement from other hosts in the downstream network.
4485 [DHCPPrefixDelegation]
4486 UplinkInterface=enp1s0
4488 Announce=yes
</programlisting>
4490 <para>This will enable DHCPv6-PD on the interface enp1s0 as an upstream interface where the
4491 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
4492 The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network.
4497 <title>IPv6 Prefix Delegation (DHCPv4
6RD)
</title>
4499 <programlisting># /etc/systemd/network/
55-dhcpv4-
6rd-upstream.network
4506 # When DHCPv4-
6RD is used, the upstream network does not support IPv6.
4507 # Hence, it is not necessary to wait for Router Advertisement, which is enabled by default.
4511 Use6RD=yes
</programlisting>
4513 <programlisting># /etc/systemd/network/
55-dhcpv4-
6rd-downstream.network
4518 DHCPPrefixDelegation=yes
4521 # It is expected that the host is acting as a router. So, usually it is not
4522 # necessary to receive Router Advertisement from other hosts in the downstream network.
4525 [DHCPPrefixDelegation]
4526 UplinkInterface=enp1s0
4528 Announce=yes
</programlisting>
4530 <para>This will enable DHCPv4-
6RD on the interface enp1s0 as an upstream interface where the
4531 DHCPv4 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
4532 The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network.
4537 <title>A bridge with two enslaved links
</title>
4539 <programlisting># /etc/systemd/network/
25-bridge-static.network
4544 Address=
192.168.0.15/
24
4546 DNS=
192.168.0.1</programlisting>
4548 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
4553 Bridge=bridge0
</programlisting>
4555 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
4560 Bridge=bridge0
</programlisting>
4562 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
4563 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
4564 and network assigned, and a default route via the specified gateway will be
4565 added. The specified DNS server will be added to the global list of DNS resolvers.
4570 <title>Bridge port with VLAN forwarding
</title>
4573 # /etc/systemd/network/
25-bridge-slave-interface-
1.network
4589 EgressUntagged=
300-
400</programlisting>
4591 <para>This overrides the configuration specified in the previous example for the
4592 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
4593 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
4594 untagged when they leave on this interface. Untagged packets which arrive on this
4595 interface will be assigned VLAN ID
42.
</para>
4599 <title>Various tunnels
</title>
4601 <programlisting>/etc/systemd/network/
25-tunnels.network
4612 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
4618 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
4624 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
4630 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
4636 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
4637 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
4641 <title>A bond device
</title>
4643 <programlisting># /etc/systemd/network/
30-bond1.network
4651 <programlisting># /etc/systemd/network/
30-bond1.netdev
4657 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
4659 MACAddress=
52:
54:
00:e9:
64:
41
4665 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
4667 MACAddress=
52:
54:
00:e9:
64:
42
4673 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
4674 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
4675 will be used to acquire an address.
</para>
4679 <title>Virtual Routing and Forwarding (VRF)
</title>
4680 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
4681 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
4682 within the routing table defined during VRF creation. For kernels before
4.8 traffic
4683 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
4685 <programlisting># /etc/systemd/network/
25-vrf.network
4695 <title>MacVTap
</title>
4696 <para>This brings up a network interface
<literal>macvtap-test
</literal>
4697 and attaches it to
<literal>enp0s25
</literal>.
</para>
4698 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
4703 MACVTAP=macvtap-test
4708 <title>A Xfrm interface with physical underlying device.
</title>
4710 <programlisting># /etc/systemd/network/
27-xfrm.netdev
4716 InterfaceId=
7</programlisting>
4718 <programlisting># /etc/systemd/network/
27-eth0.network
4723 Xfrm=xfrm0
</programlisting>
4725 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
4726 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
4727 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
4733 <title>See Also
</title>
4735 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
4736 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
4737 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4738 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4739 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob