2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
6 <refentry id=
"systemd.network" conditional='ENABLE_NETWORKD'
7 xmlns:
xi=
"http://www.w3.org/2001/XInclude">
10 <title>systemd.network
</title>
11 <productname>systemd
</productname>
15 <refentrytitle>systemd.network
</refentrytitle>
16 <manvolnum>5</manvolnum>
20 <refname>systemd.network
</refname>
21 <refpurpose>Network configuration
</refpurpose>
25 <para><filename><replaceable>network
</replaceable>.network
</filename></para>
29 <title>Description
</title>
31 <para>A plain ini-style text file that encodes network configuration for matching network interfaces,
33 <citerefentry><refentrytitle>systemd-networkd
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
34 See
<citerefentry><refentrytitle>systemd.syntax
</refentrytitle><manvolnum>7</manvolnum></citerefentry>
35 for a general description of the syntax.
</para>
37 <para>The main network file must have the extension
<filename>.network
</filename>; other
38 extensions are ignored. Networks are applied to links whenever the links appear.
</para>
40 <para>The
<filename>.network
</filename> files are read from the files located in the system network
41 directories
<filename>/usr/lib/systemd/network
</filename> and
42 <filename>/usr/local/lib/systemd/network
</filename>, the volatile runtime network directory
43 <filename>/run/systemd/network
</filename> and the local administration network directory
44 <filename>/etc/systemd/network
</filename>. All configuration files are collectively sorted and processed
45 in lexical order, regardless of the directories in which they live. However, files with identical
46 filenames replace each other. Files in
<filename>/etc/
</filename> have the highest priority, files in
47 <filename>/run/
</filename> take precedence over files with the same name under
48 <filename>/usr/
</filename>. This can be used to override a system-supplied configuration file with a local
49 file if needed. As a special case, an empty file (file size
0) or symlink with the same name pointing to
50 <filename>/dev/null
</filename> disables the configuration file entirely (it is
"masked").
</para>
52 <para>Along with the network file
<filename>foo.network
</filename>, a
"drop-in" directory
53 <filename>foo.network.d/
</filename> may exist. All files with the suffix
54 <literal>.conf
</literal> from this directory will be parsed after the file itself is
55 parsed. This is useful to alter or add configuration settings, without having to modify the main
56 configuration file. Each drop-in file must have appropriate section headers.
</para>
58 <para>In addition to
<filename>/etc/systemd/network
</filename>, drop-in
<literal>.d
</literal>
59 directories can be placed in
<filename>/usr/lib/systemd/network
</filename> or
60 <filename>/run/systemd/network
</filename> directories. Drop-in files in
61 <filename>/etc/
</filename> take precedence over those in
<filename>/run/
</filename> which in turn
62 take precedence over those in
<filename>/usr/lib/
</filename>. Drop-in files under any of these
63 directories take precedence over the main network file wherever located.
</para>
67 <title>[Match] Section Options
</title>
69 <para>The network file contains a [Match] section, which determines if a given network file may be
70 applied to a given device; and a [Network] section specifying how the device should be configured. The
71 first (in lexical order) of the network files that matches a given device is applied, all later files
72 are ignored, even if they match as well.
</para>
74 <para>A network file is said to match a network interface if all matches specified by the [Match]
75 section are satisfied. When a network file does not contain valid settings in [Match] section, then the
76 file will match all interfaces and
<command>systemd-networkd
</command> warns about that. Hint: to avoid
77 the warning and to make it clear that all interfaces shall be matched, add the following:
78 <programlisting>Name=*
</programlisting> The following keys are accepted:
</para>
80 <variablelist class='network-directives'
>
81 <xi:include href=
"systemd.link.xml" xpointer=
"mac-address" />
82 <xi:include href=
"systemd.link.xml" xpointer=
"permanent-mac-address" />
83 <xi:include href=
"systemd.link.xml" xpointer=
"path" />
84 <xi:include href=
"systemd.link.xml" xpointer=
"driver" />
85 <xi:include href=
"systemd.link.xml" xpointer=
"type" />
86 <xi:include href=
"systemd.link.xml" xpointer=
"property" />
89 <term><varname>Name=
</varname></term>
91 <para>A whitespace-separated list of shell-style globs matching the device name, as exposed
92 by the udev property
<literal>INTERFACE
</literal>, or device's alternative names. If the
93 list is prefixed with a
"!", the test is inverted.
</para>
98 <term><varname>WLANInterfaceType=
</varname></term>
100 <para>A whitespace-separated list of wireless network type. Supported values are
101 <literal>ad-hoc
</literal>,
<literal>station
</literal>,
<literal>ap
</literal>,
102 <literal>ap-vlan
</literal>,
<literal>wds
</literal>,
<literal>monitor
</literal>,
103 <literal>mesh-point
</literal>,
<literal>p2p-client
</literal>,
<literal>p2p-go
</literal>,
104 <literal>p2p-device
</literal>,
<literal>ocb
</literal>, and
<literal>nan
</literal>. If the
105 list is prefixed with a
"!", the test is inverted.
111 <term><varname>SSID=
</varname></term>
113 <para>A whitespace-separated list of shell-style globs matching the SSID of the currently
114 connected wireless LAN. If the list is prefixed with a
"!", the test is inverted.
120 <term><varname>BSSID=
</varname></term>
122 <para>A whitespace-separated list of hardware address of the currently connected wireless
123 LAN. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example in
124 <varname>MACAddress=
</varname>. This option may appear more than once, in which case the
125 lists are merged. If the empty string is assigned to this option, the list is reset.
</para>
129 <xi:include href=
"systemd.link.xml" xpointer=
"host" />
130 <xi:include href=
"systemd.link.xml" xpointer=
"virtualization" />
131 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-command-line" />
132 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-version" />
133 <xi:include href=
"systemd.link.xml" xpointer=
"architecture" />
139 <title>[Link] Section Options
</title>
141 <para> The [Link] section accepts the following keys:
</para>
143 <variablelist class='network-directives'
>
145 <term><varname>MACAddress=
</varname></term>
147 <para>The hardware address to set for the device.
</para>
151 <term><varname>MTUBytes=
</varname></term>
153 <para>The maximum transmission unit in bytes to set for the
154 device. The usual suffixes K, M, G, are supported and are
155 understood to the base of
1024.
</para>
156 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
157 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
161 <term><varname>ARP=
</varname></term>
163 <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol)
164 for this interface is enabled. When unset, the kernel's default will be used.
</para>
165 <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
166 interfaces atop a single lower-level physical interface, which will then only serve as a
167 link/
"bridge" device aggregating traffic to the same physical link and not participate in
168 the network otherwise. Defaults to unset.
</para>
172 <term><varname>Multicast=
</varname></term>
174 <para>Takes a boolean. If set to true, the multicast flag on the device is enabled. Defaults to unset.
</para>
178 <term><varname>AllMulticast=
</varname></term>
180 <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the network.
181 This happens when multicast routing is enabled. Defaults to unset.
</para>
185 <term><varname>Promiscuous=
</varname></term>
187 <para>Takes a boolean. If set to true, promiscuous mode of the interface is enabled.
188 Defaults to unset.
</para>
192 <term><varname>Unmanaged=
</varname></term>
194 <para>Takes a boolean. When
<literal>yes
</literal>, no attempts are
195 made to bring up or configure matching links, equivalent to
196 when there are no matching network files. Defaults to
197 <literal>no
</literal>.
</para>
198 <para>This is useful for preventing later matching network
199 files from interfering with certain interfaces that are fully
200 controlled by other applications.
</para>
204 <term><varname>Group=
</varname></term>
206 <para>Link groups are similar to port ranges found in managed switches.
207 When network interfaces are added to a numbered group, operations on
208 all the interfaces from that group can be performed at once. An unsigned
209 integer in the range
0…
4294967294. Defaults to unset.
</para>
213 <term><varname>RequiredForOnline=
</varname></term>
215 <para>Takes a boolean or a minimum operational state and an optional maximum operational state.
216 Please see
<citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
217 for possible operational states. When
<literal>yes
</literal>, the network is deemed required when
218 determining whether the system is online when running
219 <command>systemd-networkd-wait-online
</command>. When
<literal>no
</literal>, the network is ignored
220 when checking for online state. When a minimum operational state and an optional maximum operational
221 state are set,
<literal>yes
</literal> is implied, and this controls the minimum and maximum
222 operational state required for the network interface to be considered online.
223 Defaults to
<literal>yes
</literal>.
</para>
225 <para>The network will be brought up normally in all cases, but in
226 the event that there is no address being assigned by DHCP or the
227 cable is not plugged in, the link will simply remain offline and be
228 skipped automatically by
<command>systemd-networkd-wait-online
</command>
229 if
<literal>RequiredForOnline=no
</literal>.
</para>
233 <term><varname>ActivationPolicy=
</varname></term>
235 <para>Specifies the policy for
<command>systemd-networkd
</command> managing the link
236 administrative state. Specifically, this controls how
<command>systemd-networkd
</command>
237 changes the network device's
<literal>IFF_UP
</literal> flag, which is sometimes
238 controlled by system administrators by running e.g.,
<command>ip set dev eth0 up
</command>
239 or
<command>ip set dev eth0 down
</command>, and can also be changed with
240 <command>networkctl up eth0
</command> or
<command>networkctl down eth0
</command>.
</para>
242 <para>Takes one of
<literal>up
</literal>,
<literal>always-up
</literal>,
243 <literal>manual
</literal>,
<literal>always-down
</literal>,
<literal>down
</literal>,
244 or
<literal>bound
</literal>. When
<literal>manual
</literal>,
<command>systemd-networkd
</command>
245 will not change the link's admin state automatically; the system administrator must bring the
246 interface up or down manually, as desired. When
<literal>up
</literal> (the default) or
247 <literal>always-up
</literal>, or
<literal>down
</literal> or
<literal>always-down
</literal>,
248 <command>systemd-networkd
</command> will set the link up or down, respectively,
249 when the interface is (re)configured. When
<literal>always-up
</literal> or
250 <literal>always-down
</literal>,
<command>systemd-networkd
</command> will set the link up
251 or down, respectively, any time
<command>systemd-networkd
</command> detects a change in
252 the administrative state. When
<varname>BindCarrier=
</varname> is also set, this is
253 automatically set to
<literal>bound
</literal> and any other value is ignored.
</para>
255 <para>The administrative state is not the same as the carrier state, so using
256 <literal>always-up
</literal> does not mean the link will never lose carrier. The link
257 carrier depends on both the administrative state as well as the network device's physical
258 connection. However, to avoid reconfiguration failures, when using
<literal>always-up
</literal>,
259 <varname>IgnoreCarrierLoss=
</varname> is forced to true.
</para>
266 <title>[SR-IOV] Section Options
</title>
267 <para>The [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to configure
268 several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource into virtual
269 PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV improves
270 north-south network performance (that is, traffic with endpoints outside the host machine) by allowing
271 traffic to bypass the host machine’s network stack.
</para>
273 <variablelist class='network-directives'
>
275 <term><varname>VirtualFunction=
</varname></term>
277 <para>Specifies a Virtual Function (VF), lightweight PCIe function designed solely to move data
278 in and out. Takes an unsigned integer in the range
0…
2147483646. This option is compulsory.
</para>
283 <term><varname>VLANId=
</varname></term>
285 <para>Specifies VLAN ID of the virtual function. Takes an unsigned integer in the range
1…
4095.
</para>
290 <term><varname>QualityOfService=
</varname></term>
292 <para>Specifies quality of service of the virtual function. Takes an unsigned integer in the range
1…
4294967294.
</para>
297 <term><varname>VLANProtocol=
</varname></term>
299 <para>Specifies VLAN protocol of the virtual function. Takes
<literal>802.1Q
</literal> or
300 <literal>802.1ad
</literal>.
</para>
305 <term><varname>MACSpoofCheck=
</varname></term>
307 <para>Takes a boolean. Controls the MAC spoof checking. When unset, the kernel's default will be used.
</para>
312 <term><varname>QueryReceiveSideScaling=
</varname></term>
314 <para>Takes a boolean. Toggle the ability of querying the receive side scaling (RSS)
315 configuration of the virtual function (VF). The VF RSS information like RSS hash key may be
316 considered sensitive on some devices where this information is shared between VF and the
317 physical function (PF). When unset, the kernel's default will be used.
</para>
322 <term><varname>Trust=
</varname></term>
324 <para>Takes a boolean. Allows to set trust mode of the virtual function (VF). When set, VF
325 users can set a specific feature which may impact security and/or performance. When unset,
326 the kernel's default will be used.
</para>
331 <term><varname>LinkState=
</varname></term>
333 <para>Allows to set the link state of the virtual function (VF). Takes a boolean or a
334 special value
<literal>auto
</literal>. Setting to
<literal>auto
</literal> means a
335 reflection of the physical function (PF) link state,
<literal>yes
</literal> lets the VF to
336 communicate with other VFs on this host even if the PF link state is down,
337 <literal>no
</literal> causes the hardware to drop any packets sent by the VF. When unset,
338 the kernel's default will be used.
</para>
343 <term><varname>MACAddress=
</varname></term>
345 <para>Specifies the MAC address for the virtual function.
</para>
352 <title>[Network] Section Options
</title>
354 <para>The [Network] section accepts the following keys:
</para>
356 <variablelist class='network-directives'
>
358 <term><varname>Description=
</varname></term>
360 <para>A description of the device. This is only used for
361 presentation purposes.
</para>
365 <term><varname>DHCP=
</varname></term>
367 <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
368 <literal>yes
</literal>,
<literal>no
</literal>,
369 <literal>ipv4
</literal>, or
<literal>ipv6
</literal>. Defaults
370 to
<literal>no
</literal>.
</para>
372 <para>Note that DHCPv6 will by default be triggered by Router
373 Advertisement, if that is enabled, regardless of this parameter.
374 By enabling DHCPv6 support explicitly, the DHCPv6 client will
375 be started regardless of the presence of routers on the link,
376 or what flags the routers pass. See
377 <literal>IPv6AcceptRA=
</literal>.
</para>
379 <para>Furthermore, note that by default the domain name
380 specified through DHCP is not used for name resolution.
381 See option
<option>UseDomains=
</option> below.
</para>
383 <para>See the [DHCPv4] or [DHCPv6] sections below for further configuration options for the DHCP
384 client support.
</para>
388 <term><varname>DHCPServer=
</varname></term>
390 <para>Takes a boolean. If set to
<literal>yes
</literal>, DHCPv4 server will be started. Defaults
391 to
<literal>no
</literal>. Further settings for the DHCP server may be set in the [DHCPServer]
392 section described below.
</para>
396 <term><varname>LinkLocalAddressing=
</varname></term>
398 <para>Enables link-local address autoconfiguration. Accepts
<option>yes
</option>,
399 <option>no
</option>,
<option>ipv4
</option>, and
<option>ipv6
</option>. An IPv6 link-local address
400 is configured when
<option>yes
</option> or
<option>ipv6
</option>. An IPv4 link-local address is
401 configured when
<option>yes
</option> or
<option>ipv4
</option> and when DHCPv4 autoconfiguration
402 has been unsuccessful for some time. (IPv4 link-local address autoconfiguration will usually
403 happen in parallel with repeated attempts to acquire a DHCPv4 lease).
</para>
405 <para>Defaults to
<option>no
</option> when
<varname>Bridge=yes
</varname> is set, and
406 <option>ipv6
</option> otherwise.
</para>
410 <term><varname>IPv6LinkLocalAddressGenerationMode=
</varname></term>
412 <para>Specifies how IPv6 link local address is generated. Takes one of
<literal>eui64
</literal>,
413 <literal>none
</literal>,
<literal>stable-privacy
</literal> and
<literal>random
</literal>.
414 When unset, the kernel's default will be used. Note that if
<varname>LinkLocalAdressing=
</varname>
415 not configured as
<literal>ipv6
</literal> then
<varname>IPv6LinkLocalAddressGenerationMode=
</varname>
420 <term><varname>IPv4LLRoute=
</varname></term>
422 <para>Takes a boolean. If set to true, sets up the route needed for
423 non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
429 <term><varname>DefaultRouteOnDevice=
</varname></term>
431 <para>Takes a boolean. If set to true, sets up the default route bound to the interface.
432 Defaults to false. This is useful when creating routes on point-to-point interfaces.
433 This is equivalent to e.g. the following.
434 <programlisting>ip route add default dev veth99
</programlisting></para>
438 <term><varname>IPv6Token=
</varname></term>
440 <para>Specifies an optional address generation mode for the Stateless Address
441 Autoconfiguration (SLAAC). Supported modes are
<literal>prefixstable
</literal> and
442 <literal>static
</literal>.
</para>
444 <para>When the mode is set to
<literal>static
</literal>, an IPv6 address must be
445 specified after a colon (
<literal>:
</literal>), and the lower bits of the supplied
446 address are combined with the upper bits of a prefix received in a Router Advertisement
447 (RA) message to form a complete address. Note that if multiple prefixes are received in an
448 RA message, or in multiple RA messages, addresses will be formed from each of them using
449 the supplied address. This mode implements SLAAC but uses a static interface identifier
450 instead of an identifier generated by using the EUI-
64 algorithm. Because the interface
451 identifier is static, if Duplicate Address Detection detects that the computed address is a
452 duplicate (in use by another node on the link), then this mode will fail to provide an
453 address for that prefix. If an IPv6 address without mode is specified, then
454 <literal>static
</literal> mode is assumed.
</para>
456 <para>When the mode is set to
<literal>prefixstable
</literal> the
457 <ulink url=
"https://tools.ietf.org/html/rfc7217">RFC
7217</ulink> algorithm for generating
458 interface identifiers will be used. This mode can optionally take an IPv6 address separated
459 with a colon (
<literal>:
</literal>). If an IPv6 address is specified, then an interface
460 identifier is generated only when a prefix received in an RA message matches the supplied
463 <para>If no address generation mode is specified (which is the default), or a received
464 prefix does not match any of the addresses provided in
<literal>prefixstable
</literal>
465 mode, then the EUI-
64 algorithm will be used to form an interface identifier for that
466 prefix. This mode is also SLAAC, but with a potentially stable interface identifier which
467 does not directly map to the interface's hardware address.
</para>
469 <para>Note that the
<literal>prefixstable
</literal> algorithm uses both the interface
470 name and MAC address as input to the hash to compute the interface identifier, so if either
471 of those are changed the resulting interface identifier (and address) will change, even if
472 the prefix received in the RA message has not changed.
</para>
474 <para>This setting can be specified multiple times. If an empty string is assigned, then
475 the all previous assignments are cleared.
</para>
478 <programlisting>IPv6Token=::
1a:
2b:
3c:
4d
479 IPv6Token=static:::
1a:
2b:
3c:
4d
480 IPv6Token=prefixstable
481 IPv6Token=prefixstable:
2002:da8:
1::
</programlisting></para>
485 <term><varname>LLMNR=
</varname></term>
487 <para>Takes a boolean or
<literal>resolve
</literal>. When true,
489 url=
"https://tools.ietf.org/html/rfc4795">Link-Local
490 Multicast Name Resolution
</ulink> on the link. When set to
491 <literal>resolve
</literal>, only resolution is enabled,
492 but not host registration and announcement. Defaults to
493 true. This setting is read by
494 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
498 <term><varname>MulticastDNS=
</varname></term>
500 <para>Takes a boolean or
<literal>resolve
</literal>. When true,
502 url=
"https://tools.ietf.org/html/rfc6762">Multicast
503 DNS
</ulink> support on the link. When set to
504 <literal>resolve
</literal>, only resolution is enabled,
505 but not host or service registration and
506 announcement. Defaults to false. This setting is read by
507 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
511 <term><varname>DNSOverTLS=
</varname></term>
513 <para>Takes a boolean or
<literal>opportunistic
</literal>.
516 url=
"https://tools.ietf.org/html/rfc7858">DNS-over-TLS
</ulink>
518 When set to
<literal>opportunistic
</literal>, compatibility with
519 non-DNS-over-TLS servers is increased, by automatically
520 turning off DNS-over-TLS servers in this case.
521 This option defines a per-interface setting for
522 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
523 global
<varname>DNSOverTLS=
</varname> option. Defaults to
524 false. This setting is read by
525 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
529 <term><varname>DNSSEC=
</varname></term>
531 <para>Takes a boolean or
<literal>allow-downgrade
</literal>. When true, enables
532 <ulink url=
"https://tools.ietf.org/html/rfc4033">DNSSEC
</ulink>
533 DNS validation support on the link. When set to
534 <literal>allow-downgrade
</literal>, compatibility with
535 non-DNSSEC capable networks is increased, by automatically
536 turning off DNSSEC in this case. This option defines a
537 per-interface setting for
538 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
539 global
<varname>DNSSEC=
</varname> option. Defaults to
540 false. This setting is read by
541 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
545 <term><varname>DNSSECNegativeTrustAnchors=
</varname></term>
546 <listitem><para>A space-separated list of DNSSEC negative
547 trust anchor domains. If specified and DNSSEC is enabled,
548 look-ups done via the interface's DNS server will be subject
549 to the list of negative trust anchors, and not require
550 authentication for the specified domains, or anything below
551 it. Use this to disable DNSSEC authentication for specific
552 private domains, that cannot be proven valid using the
553 Internet DNS hierarchy. Defaults to the empty list. This
555 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
559 <term><varname>LLDP=
</varname></term>
561 <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol commonly
562 implemented on professional routers and bridges which announces which physical port a system is connected
563 to, as well as other related data. Accepts a boolean or the special value
564 <literal>routers-only
</literal>. When true, incoming LLDP packets are accepted and a database of all LLDP
565 neighbors maintained. If
<literal>routers-only
</literal> is set only LLDP data of various types of routers
566 is collected and LLDP data about other types of devices ignored (such as stations, telephones and
567 others). If false, LLDP reception is disabled. Defaults to
<literal>routers-only
</literal>. Use
568 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry> to query the
569 collected neighbor data. LLDP is only available on Ethernet links. See
<varname>EmitLLDP=
</varname> below
570 for enabling LLDP packet emission from the local system.
575 <term><varname>EmitLLDP=
</varname></term>
577 <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the special values
578 <literal>nearest-bridge
</literal>,
<literal>non-tpmr-bridge
</literal> and
579 <literal>customer-bridge
</literal>. Defaults to false, which turns off LLDP packet emission. If not false,
580 a short LLDP packet with information about the local system is sent out in regular intervals on the
581 link. The LLDP packet will contain information about the local hostname, the local machine ID (as stored
582 in
<citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and the
583 local interface name, as well as the pretty hostname of the system (as set in
584 <citerefentry><refentrytitle>machine-info
</refentrytitle><manvolnum>5</manvolnum></citerefentry>). LLDP
585 emission is only available on Ethernet links. Note that this setting passes data suitable for
586 identification of host to the network and should thus not be enabled on untrusted networks, where such
587 identification data should not be made available. Use this option to permit other systems to identify on
588 which interfaces they are connected to this system. The three special values control propagation of the
589 LLDP packets. The
<literal>nearest-bridge
</literal> setting permits propagation only to the nearest
590 connected bridge,
<literal>non-tpmr-bridge
</literal> permits propagation across Two-Port MAC Relays, but
591 not any other bridges, and
<literal>customer-bridge
</literal> permits propagation until a customer bridge
592 is reached. For details about these concepts, see
<ulink
593 url=
"https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE
802.1AB-
2016</ulink>. Note that
594 configuring this setting to true is equivalent to
<literal>nearest-bridge
</literal>, the recommended and
595 most restricted level of propagation. See
<varname>LLDP=
</varname> above for an option to enable LLDP
601 <term><varname>BindCarrier=
</varname></term>
603 <para>A link name or a list of link names. When set, controls the behavior of the current
604 link. When all links in the list are in an operational down state, the current link is brought
605 down. When at least one link has carrier, the current interface is brought up.
</para>
607 <para>This forces
<varname>ActivationPolicy=
</varname> to be set to
<literal>bound
</literal>.
</para>
611 <term><varname>Address=
</varname></term>
613 <para>A static IPv4 or IPv6 address and its prefix length,
614 separated by a
<literal>/
</literal> character. Specify
615 this key more than once to configure several addresses.
616 The format of the address must be as described in
617 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
618 This is a short-hand for an [Address] section only
619 containing an Address key (see below). This option may be
620 specified more than once.
623 <para>If the specified address is
<literal>0.0.0.0</literal> (for IPv4) or
<literal>::
</literal>
624 (for IPv6), a new address range of the requested size is automatically allocated from a
625 system-wide pool of unused ranges. Note that the prefix length must be equal or larger than
8 for
626 IPv4, and
64 for IPv6. The allocated range is checked against all current network interfaces and
627 all known network configuration files to avoid address range conflicts. The default system-wide
628 pool consists of
192.168.0.0/
16,
172.16.0.0/
12 and
10.0.0.0/
8 for IPv4, and fd00::/
8 for IPv6.
629 This functionality is useful to manage a large number of dynamically created network interfaces
630 with the same network configuration and automatic address range assignment.
</para>
635 <term><varname>Gateway=
</varname></term>
637 <para>The gateway address, which must be in the format
639 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
640 This is a short-hand for a [Route] section only containing
641 a Gateway key. This option may be specified more than
646 <term><varname>DNS=
</varname></term>
648 <para>A DNS server address, which must be in the format described in
649 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
650 This option may be specified more than once. Each address can optionally take a port number
651 separated with
<literal>:
</literal>, a network interface name or index separated with
652 <literal>%
</literal>, and a Server Name Indication (SNI) separated with
<literal>#
</literal>.
653 When IPv6 address is specified with a port number, then the address must be in the square
654 brackets. That is, the acceptable full formats are
655 <literal>111.222.333.444:
9953%ifname#example.com
</literal> for IPv4 and
656 <literal>[
1111:
2222::
3333]:
9953%ifname#example.com
</literal> for IPv6. If an empty string is
657 assigned, then the all previous assignments are cleared. This setting is read by
658 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
662 <term><varname>Domains=
</varname></term>
664 <para>A whitespace-separated list of domains which should be resolved using the DNS servers on
665 this link. Each item in the list should be a domain name, optionally prefixed with a tilde
666 (
<literal>~
</literal>). The domains with the prefix are called
"routing-only domains". The
667 domains without the prefix are called
"search domains" and are first used as search suffixes for
668 extending single-label hostnames (hostnames containing no dots) to become fully qualified
669 domain names (FQDNs). If a single-label hostname is resolved on this interface, each of the
670 specified search domains are appended to it in turn, converting it into a fully qualified domain
671 name, until one of them may be successfully resolved.
</para>
673 <para>Both
"search" and
"routing-only" domains are used for routing of DNS queries: look-ups for hostnames
674 ending in those domains (hence also single label names, if any
"search domains" are listed), are routed to
675 the DNS servers configured for this interface. The domain routing logic is particularly useful on
676 multi-homed hosts with DNS servers serving particular private DNS zones on each interface.
</para>
678 <para>The
"routing-only" domain
<literal>~.
</literal> (the tilde indicating definition of a routing domain,
679 the dot referring to the DNS root domain which is the implied suffix of all valid DNS names) has special
680 effect. It causes all DNS traffic which does not match another configured domain routing entry to be routed
681 to DNS servers specified for this interface. This setting is useful to prefer a certain set of DNS servers
682 if a link on which they are connected is available.
</para>
684 <para>This setting is read by
685 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
686 "Search domains" correspond to the
<varname>domain
</varname> and
<varname>search
</varname> entries in
687 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
688 Domain name routing has no equivalent in the traditional glibc API, which has no concept of domain
689 name servers limited to a specific link.
</para>
693 <term><varname>DNSDefaultRoute=
</varname></term>
695 <para>Takes a boolean argument. If true, this link's configured DNS servers are used for resolving domain
696 names that do not match any link's configured
<varname>Domains=
</varname> setting. If false, this link's
697 configured DNS servers are never used for such domains, and are exclusively used for resolving names that
698 match at least one of the domains configured on this link. If not specified defaults to an automatic mode:
699 queries not matching any link's configured domains will be routed to this link if it has no routing-only
700 domains configured.
</para>
704 <term><varname>NTP=
</varname></term>
706 <para>An NTP server address (either an IP address, or a hostname). This option may be specified more than once. This setting is read by
707 <citerefentry><refentrytitle>systemd-timesyncd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
711 <term><varname>IPForward=
</varname></term>
712 <listitem><para>Configures IP packet forwarding for the
713 system. If enabled, incoming packets on any network
714 interface will be forwarded to any other interfaces
715 according to the routing table. Takes a boolean,
716 or the values
<literal>ipv4
</literal> or
717 <literal>ipv6
</literal>, which only enable IP packet
718 forwarding for the specified address family. This controls
719 the
<filename>net.ipv4.ip_forward
</filename> and
720 <filename>net.ipv6.conf.all.forwarding
</filename> sysctl
721 options of the network interface (see
<ulink
722 url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
723 for details about sysctl options). Defaults to
724 <literal>no
</literal>.
</para>
726 <para>Note: this setting controls a global kernel option,
727 and does so one way only: if a network that has this setting
728 enabled is set up the global setting is turned on. However,
729 it is never turned off again, even after all networks with
730 this setting enabled are shut down again.
</para>
732 <para>To allow IP packet forwarding only between specific
733 network interfaces use a firewall.
</para>
737 <term><varname>IPMasquerade=
</varname></term>
738 <listitem><para>Configures IP masquerading for the network interface. If enabled, packets
739 forwarded from the network interface will be appear as coming from the local host. Takes one
740 of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
<literal>both
</literal>, or
741 <literal>no
</literal>. Defaults to
<literal>no
</literal>. If enabled, this automatically sets
742 <varname>IPForward=
</varname> to one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal> or
743 <literal>yes
</literal>.
</para>
744 <para>Note. Any positive boolean values such as
<literal>yes
</literal> or
745 <literal>true
</literal> are now deprecated. Please use one of the values in the above.
</para>
749 <term><varname>IPv6PrivacyExtensions=
</varname></term>
750 <listitem><para>Configures use of stateless temporary
751 addresses that change over time (see
<ulink
752 url=
"https://tools.ietf.org/html/rfc4941">RFC
4941</ulink>,
753 Privacy Extensions for Stateless Address Autoconfiguration
754 in IPv6). Takes a boolean or the special values
755 <literal>prefer-public
</literal> and
756 <literal>kernel
</literal>. When true, enables the privacy
757 extensions and prefers temporary addresses over public
758 addresses. When
<literal>prefer-public
</literal>, enables the
759 privacy extensions, but prefers public addresses over
760 temporary addresses. When false, the privacy extensions
761 remain disabled. When
<literal>kernel
</literal>, the kernel's
762 default setting will be left in place. Defaults to
763 <literal>no
</literal>.
</para></listitem>
766 <term><varname>IPv6AcceptRA=
</varname></term>
767 <listitem><para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the
768 interface. If true, RAs are accepted; if false, RAs are ignored. When RAs are accepted, they may
769 trigger the start of the DHCPv6 client if the relevant flags are set in the RA data, or if no
770 routers are found on the link. The default is to disable RA reception for bridge devices or when IP
771 forwarding is enabled, and to enable it otherwise. Cannot be enabled on bond devices and when link
772 local addressing is disabled.
</para>
774 <para>Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA] section, see
777 <para>Also see
<ulink
778 url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink> in the kernel
779 documentation regarding
<literal>accept_ra
</literal>, but note that systemd's setting of
780 <constant>1</constant> (i.e. true) corresponds to kernel's setting of
<constant>2</constant>.
</para>
782 <para>Note that kernel's implementation of the IPv6 RA protocol is always disabled,
783 regardless of this setting. If this option is enabled, a userspace implementation of the IPv6
784 RA protocol is used, and the kernel's own implementation remains disabled, since
785 <command>systemd-networkd
</command> needs to know all details supplied in the advertisements,
786 and these are not available from the kernel if the kernel's own implementation is used.
</para>
790 <term><varname>IPv6DuplicateAddressDetection=
</varname></term>
791 <listitem><para>Configures the amount of IPv6 Duplicate
792 Address Detection (DAD) probes to send. When unset, the kernel's default will be used.
796 <term><varname>IPv6HopLimit=
</varname></term>
797 <listitem><para>Configures IPv6 Hop Limit. For each router that
798 forwards the packet, the hop limit is decremented by
1. When the
799 hop limit field reaches zero, the packet is discarded.
800 When unset, the kernel's default will be used.
804 <term><varname>IPv4AcceptLocal=
</varname></term>
805 <listitem><para>Takes a boolean. Accept packets with local source addresses. In combination
806 with suitable routing, this can be used to direct packets between two local interfaces over
807 the wire and have them accepted properly. When unset, the kernel's default will be used.
811 <term><varname>IPv4RouteLocalnet=
</varname></term>
812 <listitem><para>Takes a boolean. When true, the kernel does not consider loopback addresses as martian source or destination
813 while routing. This enables the use of
127.0.0.0/
8 for local routing purposes. When unset, the kernel's default will be used.
817 <term><varname>IPv4ProxyARP=
</varname></term>
818 <listitem><para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one host,
819 usually a router, answers ARP requests intended for another machine. By
"faking" its identity,
820 the router accepts responsibility for routing packets to the
"real" destination. See
<ulink
821 url=
"https://tools.ietf.org/html/rfc1027">RFC
1027</ulink>.
822 When unset, the kernel's default will be used.
826 <term><varname>IPv6ProxyNDP=
</varname></term>
827 <listitem><para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery
828 Protocol) is a technique for IPv6 to allow routing of addresses to a different
829 destination when peers expect them to be present on a certain physical link.
830 In this case a router answers Neighbour Advertisement messages intended for
831 another machine by offering its own MAC address as destination.
832 Unlike proxy ARP for IPv4, it is not enabled globally, but will only send Neighbour
833 Advertisement messages for addresses in the IPv6 neighbor proxy table,
834 which can also be shown by
<command>ip -
6 neighbour show proxy
</command>.
835 systemd-networkd will control the per-interface `proxy_ndp` switch for each configured
836 interface depending on this option.
837 When unset, the kernel's default will be used.
841 <term><varname>IPv6ProxyNDPAddress=
</varname></term>
842 <listitem><para>An IPv6 address, for which Neighbour Advertisement messages will be
843 proxied. This option may be specified more than once. systemd-networkd will add the
844 <option>IPv6ProxyNDPAddress=
</option> entries to the kernel's IPv6 neighbor proxy table.
845 This option implies
<option>IPv6ProxyNDP=yes
</option> but has no effect if
846 <option>IPv6ProxyNDP
</option> has been set to false. When unset, the kernel's default will be used.
850 <term><varname>IPv6SendRA=
</varname></term>
851 <listitem><para>Whether to enable or disable Router Advertisement sending on a link. Takes a
852 boolean value. When enabled, prefixes configured in [IPv6Prefix] sections and routes
853 configured in [IPv6RoutePrefix] sections are distributed as defined in the [IPv6SendRA]
854 section. If
<varname>DHCPv6PrefixDelegation=
</varname> is enabled, then the delegated
855 prefixes are also distributed. See
<varname>DHCPv6PrefixDelegation=
</varname> setting and the
856 [IPv6SendRA], [IPv6Prefix], [IPv6RoutePrefix], and [DHCPv6PrefixDelegation] sections for more
857 configuration options.
</para></listitem>
860 <term><varname>DHCPv6PrefixDelegation=
</varname></term>
861 <listitem><para>Takes a boolean value. When enabled, requests prefixes using a DHCPv6 client
862 configured on another link. By default, an address within each delegated prefix will be
863 assigned, and the prefixes will be announced through IPv6 Router Advertisement when
864 <varname>IPv6SendRA=
</varname> is enabled. Such default settings can be configured in
865 [DHCPv6PrefixDelegation] section. Defaults to disabled.
</para></listitem>
868 <term><varname>IPv6MTUBytes=
</varname></term>
869 <listitem><para>Configures IPv6 maximum transmission unit (MTU).
870 An integer greater than or equal to
1280 bytes. When unset, the kernel's default will be used.
874 <term><varname>Bridge=
</varname></term>
876 <para>The name of the bridge to add the link to. See
877 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
882 <term><varname>Bond=
</varname></term>
884 <para>The name of the bond to add the link to. See
885 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
890 <term><varname>VRF=
</varname></term>
892 <para>The name of the VRF to add the link to. See
893 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
898 <term><varname>VLAN=
</varname></term>
900 <para>The name of a VLAN to create on the link. See
901 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
902 This option may be specified more than once.
</para>
906 <term><varname>IPVLAN=
</varname></term>
908 <para>The name of a IPVLAN to create on the link. See
909 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
910 This option may be specified more than once.
</para>
914 <term><varname>MACVLAN=
</varname></term>
916 <para>The name of a MACVLAN to create on the link. See
917 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
918 This option may be specified more than once.
</para>
922 <term><varname>VXLAN=
</varname></term>
924 <para>The name of a VXLAN to create on the link. See
925 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
926 This option may be specified more than once.
</para>
930 <term><varname>Tunnel=
</varname></term>
932 <para>The name of a Tunnel to create on the link. See
933 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
934 This option may be specified more than once.
</para>
938 <term><varname>MACsec=
</varname></term>
940 <para>The name of a MACsec device to create on the link. See
941 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
942 This option may be specified more than once.
</para>
946 <term><varname>ActiveSlave=
</varname></term>
948 <para>Takes a boolean. Specifies the new active slave. The
<literal>ActiveSlave=
</literal>
949 option is only valid for following modes:
950 <literal>active-backup
</literal>,
951 <literal>balance-alb
</literal> and
952 <literal>balance-tlb
</literal>. Defaults to false.
957 <term><varname>PrimarySlave=
</varname></term>
959 <para>Takes a boolean. Specifies which slave is the primary device. The specified
960 device will always be the active slave while it is available. Only when the
961 primary is off-line will alternate devices be used. This is useful when
962 one slave is preferred over another, e.g. when one slave has higher throughput
963 than another. The
<literal>PrimarySlave=
</literal> option is only valid for
965 <literal>active-backup
</literal>,
966 <literal>balance-alb
</literal> and
967 <literal>balance-tlb
</literal>. Defaults to false.
972 <term><varname>ConfigureWithoutCarrier=
</varname></term>
974 <para>Takes a boolean. Allows networkd to configure a specific link even if it has no carrier.
975 Defaults to false. If
<option>IgnoreCarrierLoss=
</option> is not explicitly set, it will
976 default to this value.
981 <term><varname>IgnoreCarrierLoss=
</varname></term>
983 <para>Takes a boolean. Allows networkd to retain both the static and dynamic configuration
984 of the interface even if its carrier is lost. When unset, the value specified with
985 <option>ConfigureWithoutCarrier=
</option> is used.
988 <para>When
<varname>ActivationPolicy=
</varname> is set to
<literal>always-up
</literal>, this
989 is forced to
<literal>true
</literal>.
994 <term><varname>Xfrm=
</varname></term>
996 <para>The name of the xfrm to create on the link. See
997 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
998 This option may be specified more than once.
</para>
1002 <term><varname>KeepConfiguration=
</varname></term>
1004 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
1005 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
1006 will not drop static addresses and routes on starting up process. When set to
1007 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
1008 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
1009 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
1010 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
1011 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
1012 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
1013 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
<literal>no
</literal>.
1018 <term><varname>BatmanAdvanced=
</varname></term>
1020 <para>The name of the B.A.T.M.A.N. Advanced interface to add the link to. See
1021 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1030 <title>[Address] Section Options
</title>
1032 <para>An [Address] section accepts the following keys. Specify several [Address]
1033 sections to configure several addresses.
</para>
1035 <variablelist class='network-directives'
>
1037 <term><varname>Address=
</varname></term>
1039 <para>As in the [Network] section. This key is mandatory. Each [Address] section can contain one
1040 <varname>Address=
</varname> setting.
</para>
1044 <term><varname>Peer=
</varname></term>
1046 <para>The peer address in a point-to-point connection.
1047 Accepts the same format as the
<varname>Address=
</varname>
1052 <term><varname>Broadcast=
</varname></term>
1054 <para>Takes an IPv4 address or boolean value. The address must be in the format described in
1055 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
1056 If set to true, then the IPv4 broadcast address will be derived from the
1057 <varname>Address=
</varname> setting. If set to false, then the broadcast address will not
1058 be set. Defaults to true, except for wireguard interfaces, where it default to false.
1063 <term><varname>Label=
</varname></term>
1065 <para>An address label.
</para>
1069 <term><varname>PreferredLifetime=
</varname></term>
1071 <para>Allows the default
"preferred lifetime" of the address to be overridden. Only three
1072 settings are accepted:
<literal>forever
</literal>,
<literal>infinity
</literal>, which is the
1073 default and means that the address never expires, and
<literal>0</literal>, which means that the
1074 address is considered immediately
"expired" and will not be used, unless explicitly requested. A
1075 setting of
<option>PreferredLifetime=
0</option> is useful for addresses which are added to be
1076 used only by a specific application, which is then configured to use them explicitly.
</para>
1080 <term><varname>Scope=
</varname></term>
1082 <para>The scope of the address, which can be
1083 <literal>global
</literal> (valid everywhere on the network, even through a gateway),
1084 <literal>link
</literal> (only valid on this device, will not traverse a gateway) or
1085 <literal>host
</literal> (only valid within the device itself, e.g.
127.0.0.1)
1086 or an unsigned integer in the range
0…
255.
1087 Defaults to
<literal>global
</literal>.
</para>
1091 <term><varname>HomeAddress=
</varname></term>
1093 <para>Takes a boolean. Designates this address the
"home address" as defined in
1094 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>.
1095 Supported only on IPv6. Defaults to false.
</para>
1099 <term><varname>DuplicateAddressDetection=
</varname></term>
1101 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
1102 <literal>both
</literal>,
<literal>none
</literal>. When
<literal>ipv4
</literal>,
1103 performs IPv4 Duplicate Address Detection. See
1104 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5224</ulink>.
1105 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
1106 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>.
1107 Defaults to
<literal>ipv6
</literal>.
</para>
1111 <term><varname>ManageTemporaryAddress=
</varname></term>
1113 <para>Takes a boolean. If true the kernel manage temporary addresses created
1114 from this one as template on behalf of Privacy Extensions
1115 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become
1116 active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
1117 The given address needs to have a prefix length of
64. This flag allows using privacy
1118 extensions in a manually configured network, just like if stateless auto-configuration
1119 was active. Defaults to false.
</para>
1123 <term><varname>AddPrefixRoute=
</varname></term>
1125 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
1126 Defaults to true.
</para>
1130 <term><varname>AutoJoin=
</varname></term>
1132 <para>Takes a boolean. Joining multicast group on ethernet level via
1133 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
1134 IGMP snooping since the switch would not replicate multicast packets on ports that did not
1135 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
1136 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
1137 that enables then to do the required join. By extending ip address command with option
1138 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
1139 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
1140 Defaults to
<literal>no
</literal>.
</para>
1147 <title>[Neighbor] Section Options
</title>
1148 <para>A [Neighbor] section accepts the following keys. The neighbor section adds a permanent, static
1149 entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the links
1150 matched for the network. Specify several [Neighbor] sections to configure several static neighbors.
1153 <variablelist class='network-directives'
>
1155 <term><varname>Address=
</varname></term>
1157 <para>The IP address of the neighbor.
</para>
1161 <term><varname>LinkLayerAddress=
</varname></term>
1163 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1170 <title>[IPv6AddressLabel] Section Options
</title>
1172 <para>An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel]
1173 sections to configure several address labels. IPv6 address labels are used for address selection. See
1174 <ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>. Precedence is managed by userspace,
1175 and only the label itself is stored in the kernel.
</para>
1177 <variablelist class='network-directives'
>
1179 <term><varname>Label=
</varname></term>
1181 <para>The label for the prefix, an unsigned integer in the range
0–
4294967294.
1182 0xffffffff is reserved. This setting is mandatory.
</para>
1186 <term><varname>Prefix=
</varname></term>
1188 <para>IPv6 prefix is an address with a prefix length, separated by a slash
<literal>/
</literal> character.
1189 This key is mandatory.
</para>
1196 <title>[RoutingPolicyRule] Section Options
</title>
1198 <para>An [RoutingPolicyRule] section accepts the following keys. Specify several [RoutingPolicyRule]
1199 sections to configure several rules.
</para>
1201 <variablelist class='network-directives'
>
1203 <term><varname>TypeOfService=
</varname></term>
1205 <para>Takes a number between
0 and
255 that specifies the type of service to match.
</para>
1209 <term><varname>From=
</varname></term>
1211 <para>Specifies the source address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1215 <term><varname>To=
</varname></term>
1217 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1221 <term><varname>FirewallMark=
</varname></term>
1223 <para>Specifies the iptables firewall mark value to match (a number between
1 and
1224 4294967295). Optionally, the firewall mask (also a number between
1 and
4294967295) can be
1225 suffixed with a slash (
<literal>/
</literal>), e.g.,
<literal>7/
255</literal>.
</para>
1229 <term><varname>Table=
</varname></term>
1231 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes one of predefined names
1232 <literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname>
1233 in
<citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1234 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1238 <term><varname>Priority=
</varname></term>
1240 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an unsigned
1241 integer. Higher number means lower priority, and rules get processed in order of increasing number.
</para>
1245 <term><varname>IncomingInterface=
</varname></term>
1247 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches packets originating from this host.
</para>
1251 <term><varname>OutgoingInterface=
</varname></term>
1253 <para>Specifies the outgoing device to match. The outgoing interface is only available for packets originating from local sockets that are bound to a device.
</para>
1257 <term><varname>SourcePort=
</varname></term>
1259 <para>Specifies the source IP port or IP port range match in forwarding information base (FIB) rules.
1260 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1264 <term><varname>DestinationPort=
</varname></term>
1266 <para>Specifies the destination IP port or IP port range match in forwarding information base (FIB) rules.
1267 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1271 <term><varname>IPProtocol=
</varname></term>
1273 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP protocol name such as
<literal>tcp
</literal>,
1274 <literal>udp
</literal> or
<literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
<literal>tcp
</literal> or
1275 <literal>17</literal> for
<literal>udp
</literal>.
1276 Defaults to unset.
</para>
1280 <term><varname>InvertRule=
</varname></term>
1282 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1286 <term><varname>Family=
</varname></term>
1288 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1289 <literal>both
</literal>. By default, the address family is determined by the address
1290 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1291 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1292 <literal>ipv4
</literal>.
</para>
1296 <term><varname>User=
</varname></term>
1298 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1303 <term><varname>SuppressPrefixLength=
</varname></term>
1305 <para>Takes a number
<replaceable>N
</replaceable> in the range
0…
128 and rejects routing
1306 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1311 <term><varname>Type=
</varname></term>
1313 <para>Specifies Routing Policy Database (RPDB) rule type. Takes one of
<literal>blackhole
</literal>,
1314 <literal>unreachable
</literal> or
<literal>prohibit
</literal>.
1322 <title>[NextHop] Section Options
</title>
1323 <para>The [NextHop] section is used to manipulate entries in the kernel's
"nexthop" tables. The
1324 [NextHop] section accepts the following keys. Specify several [NextHop] sections to configure several
1327 <variablelist class='network-directives'
>
1329 <term><varname>Id=
</varname></term>
1331 <para>The id of the next hop. Takes an unsigned integer in the range
1…
4294967295. If left
1332 unspecified, then automatically chosen by kernel.
</para>
1336 <term><varname>Gateway=
</varname></term>
1338 <para>As in the [Network] section.
</para>
1342 <term><varname>Family=
</varname></term>
1344 <para>Takes one of the special values
<literal>ipv4
</literal> or
<literal>ipv6
</literal>.
1345 By default, the family is determined by the address specified in
1346 <varname>Gateway=
</varname>. If
<varname>Gateway=
</varname> is not specified, then defaults
1347 to
<literal>ipv4
</literal>.
</para>
1351 <term><varname>OnLink=
</varname></term>
1353 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1354 reachable directly by the current machine (i.e., attached to the local network), so that we
1355 can insert the nexthop in the kernel table without it being complained about. Defaults to
1356 <literal>no
</literal>.
</para>
1360 <term><varname>Blackhole=
</varname></term>
1362 <para>Takes a boolean. If enabled, packets to the corresponding routes are discarded
1363 silently, and
<varname>Gateway=
</varname> cannot be specified. Defaults to
1364 <literal>no
</literal>.
</para>
1371 <title>[Route] Section Options
</title>
1372 <para>The [Route] section accepts the following keys. Specify several [Route] sections to configure
1373 several routes.
</para>
1375 <variablelist class='network-directives'
>
1377 <term><varname>Gateway=
</varname></term>
1379 <para>Takes the gateway address or the special values
<literal>_dhcp4
</literal> and
1380 <literal>_ipv6ra
</literal>. If
<literal>_dhcp4
</literal> or
<literal>_ipv6ra
</literal> is
1381 set, then the gateway address provided by DHCPv4 or IPv6 RA is used.
</para>
1385 <term><varname>GatewayOnLink=
</varname></term>
1387 <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is
1388 reachable directly by the current machine (i.e., attached to the local network), so that we
1389 can insert the route in the kernel table without it being complained about. Defaults to
1390 <literal>no
</literal>.
</para>
1394 <term><varname>Destination=
</varname></term>
1396 <para>The destination prefix of the route. Possibly
1397 followed by a slash and the prefix length. If omitted, a
1398 full-length host route is assumed.
</para>
1402 <term><varname>Source=
</varname></term>
1404 <para>The source prefix of the route. Possibly followed by
1405 a slash and the prefix length. If omitted, a full-length
1406 host route is assumed.
</para>
1410 <term><varname>Metric=
</varname></term>
1412 <para>The metric of the route (an unsigned integer).
</para>
1416 <term><varname>IPv6Preference=
</varname></term>
1418 <para>Specifies the route preference as defined in
<ulink
1419 url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink> for Router Discovery messages. Which
1420 can be one of
<literal>low
</literal> the route has a lowest priority,
<literal>medium
</literal>
1421 the route has a default priority or
<literal>high
</literal> the route has a highest priority.
1426 <term><varname>Scope=
</varname></term>
1428 <para>The scope of the IPv4 route, which can be
<literal>global
</literal>,
<literal>site
</literal>,
1429 <literal>link
</literal>,
<literal>host
</literal>, or
1430 <literal>nowhere
</literal>:
</para>
1432 <listitem><para><literal>global
</literal> means the route can reach
1433 hosts more than one hop away.
</para></listitem>
1435 <listitem><para><literal>site
</literal> means an interior route in
1436 the local autonomous system.
</para></listitem>
1438 <listitem><para><literal>link
</literal> means the route can only
1439 reach hosts on the local network (one hop away).
</para></listitem>
1441 <listitem><para><literal>host
</literal> means the route will not
1442 leave the local machine (used for internal addresses like
1443 127.0.0.1).
</para></listitem>
1445 <listitem><para><literal>nowhere
</literal> means the destination
1446 doesn't exist.
</para></listitem>
1448 <para>For IPv4 route, defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
1449 <literal>local
</literal> or
<literal>nat
</literal>,
1450 and
<literal>link
</literal> if
<varname>Type=
</varname> is
1451 <literal>broadcast
</literal>,
<literal>multicast
</literal>, or
<literal>anycast
</literal>.
1452 In other cases, defaults to
<literal>global
</literal>. The value is
1453 not used for IPv6.
</para>
1457 <term><varname>PreferredSource=
</varname></term>
1459 <para>The preferred source address of the route. The address
1460 must be in the format described in
1461 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
1465 <term><varname>Table=
</varname></term>
1467 <para>The table identifier for the route. Takes one of predefined names
<literal>default
</literal>,
<literal>main
</literal>,
1468 and
<literal>local
</literal>, and names defined in
<varname>RouteTable=
</varname> in
<citerefentry><refentrytitle>networkd.conf
</refentrytitle>
1469 <manvolnum>5</manvolnum></citerefentry>, or a number between
1 and
4294967295. The table can be retrieved using
1470 <command>ip route show table
<replaceable>num
</replaceable></command>. If unset and
<varname>Type=
</varname> is
<literal>local
</literal>,
1471 <literal>broadcast
</literal>,
<literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1472 In other cases, defaults to
<literal>main
</literal>.
1477 <term><varname>Protocol=
</varname></term>
1479 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special values
1480 <literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1481 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1486 <term><varname>Type=
</varname></term>
1488 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1489 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1490 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1491 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1492 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e. a
1493 route indicating the path to take to a destination network address. If
<literal>blackhole
</literal>, packets
1494 to the defined route are discarded silently. If
<literal>unreachable
</literal>, packets to the defined route
1495 are discarded and the ICMP message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets
1496 to the defined route are discarded and the ICMP message
"Communication Administratively Prohibited" is
1497 generated. If
<literal>throw
</literal>, route lookup in the current routing table will fail and the route
1498 selection process will return to Routing Policy Database (RPDB). Defaults to
<literal>unicast
</literal>.
1503 <term><varname>InitialCongestionWindow=
</varname></term>
1505 <para>The TCP initial congestion window is used during the start of a TCP connection.
1506 During the start of a TCP session, when a client requests a resource, the server's initial
1507 congestion window determines how many packets will be sent during the initial burst of data
1508 without waiting for acknowledgement. Takes a number between
1 and
1023. Note that
100 is
1509 considered an extremely large value for this option. When unset, the kernel's default
1510 (typically
10) will be used.
</para>
1514 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1516 <para>The TCP initial advertised receive window is the amount of receive data (in bytes)
1517 that can initially be buffered at one time on a connection. The sending host can send only
1518 that amount of data before waiting for an acknowledgment and window update from the
1519 receiving host. Takes a number between
1 and
1023. Note that
100 is considered an extremely
1520 large value for this option. When unset, the kernel's default will be used.
</para>
1524 <term><varname>QuickAck=
</varname></term>
1526 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the kernel's default will be used.
1531 <term><varname>FastOpenNoCookie=
</varname></term>
1533 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1534 When unset, the kernel's default will be used.
1539 <term><varname>TTLPropagate=
</varname></term>
1541 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1542 When unset, the kernel's default will be used.
1547 <term><varname>MTUBytes=
</varname></term>
1549 <para>The maximum transmission unit in bytes to set for the
1550 route. The usual suffixes K, M, G, are supported and are
1551 understood to the base of
1024.
</para>
1552 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
1553 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
1557 <term><varname>IPServiceType=
</varname></term>
1559 <para>Takes string;
<literal>CS6
</literal> or
<literal>CS4
</literal>. Used to set IP
1560 service type to CS6 (network control) or CS4 (Realtime). Defaults to CS6.
</para>
1564 <term><varname>TCPAdvertisedMaximumSegmentSize=
</varname></term>
1566 <para>Specifies the Path MSS (in bytes) hints given on TCP layer. The usual suffixes K, M, G, are
1567 supported and are understood to the base of
1024. An unsigned integer in the range
1–
4294967294.
1568 When unset, the kernel's default will be used.
</para>
1572 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1574 <para>Configures multipath route. Multipath routing is the technique of using multiple
1575 alternative paths through a network. Takes gateway address. Optionally, takes a network
1576 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for
1577 this multipath route separated with whitespace. This setting can be specified multiple
1578 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
1582 <term><varname>NextHop=
</varname></term>
1584 <para>Specifies the nexthop id. Takes an unsigned integer in the range
1…
4294967295.
1585 If set, the corresponding [NextHop] section must be configured. Defaults to unset.
</para>
1592 <title>[DHCPv4] Section Options
</title>
1593 <para>The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the
1594 <varname>DHCP=
</varname> setting described above:
</para>
1596 <variablelist class='network-directives'
>
1598 <term><varname>UseDNS=
</varname></term>
1600 <para>When true (the default), the DNS servers received from the DHCP server will be used.
</para>
1602 <para>This corresponds to the
<option>nameserver
</option>
1603 option in
<citerefentry
1604 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1608 <term><varname>RoutesToDNS=
</varname></term>
1610 <para>When true, the routes to the DNS servers received from the DHCP server will be
1611 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored.
1612 Defaults to false.
</para>
1616 <term><varname>UseNTP=
</varname></term>
1618 <para>When true (the default), the NTP servers received from the DHCP server will be used by
1619 <filename>systemd-timesyncd.service
</filename>.
</para>
1623 <term><varname>UseSIP=
</varname></term>
1625 <para>When true (the default), the SIP servers received from the DHCP server will be collected
1626 and made available to client programs.
</para>
1631 <term><varname>UseMTU=
</varname></term>
1633 <para>When true, the interface maximum transmission unit
1634 from the DHCP server will be used on the current link.
1635 If
<varname>MTUBytes=
</varname> is set, then this setting is ignored.
1636 Defaults to false.
</para>
1640 <term><varname>Anonymize=
</varname></term>
1642 <para>Takes a boolean. When true, the options sent to the DHCP server will
1643 follow the
<ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink>
1644 (Anonymity Profiles for DHCP Clients) to minimize disclosure of identifying information.
1645 Defaults to false.
</para>
1647 <para>This option should only be set to true when
1648 <varname>MACAddressPolicy=
</varname> is set to
<literal>random
</literal>
1650 project='man-pages'
><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
</para>
1652 <para>Note that this configuration will overwrite others.
1653 In concrete, the following variables will be ignored:
1654 <varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1655 <varname>UseRoutes=
</varname>,
<varname>UseMTU=
</varname>,
1656 <varname>VendorClassIdentifier=
</varname>,
<varname>UseTimezone=
</varname>.
</para>
1658 <para>With this option enabled DHCP requests will mimic those generated by Microsoft Windows, in
1659 order to reduce the ability to fingerprint and recognize installations. This means DHCP request
1660 sizes will grow and lease data will be more comprehensive than normally, though most of the
1661 requested data is not actually used.
</para>
1665 <term><varname>SendHostname=
</varname></term>
1667 <para>When true (the default), the machine's hostname will be sent to the DHCP server.
1668 Note that the machine's hostname must consist only of
7-bit ASCII lower-case characters and
1669 no spaces or dots, and be formatted as a valid DNS domain name. Otherwise, the hostname is not
1670 sent even if this is set to true.
</para>
1675 <term><varname>MUDURL=
</varname></term>
1677 <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent to the
1678 DHCPv4 server. Takes a URL of length up to
255 characters. A superficial verification that the
1679 string is a valid URL will be performed. DHCPv4 clients are intended to have at most one MUD URL
1680 associated with them. See
<ulink url=
"https://tools.ietf.org/html/rfc8520">RFCÂ
8520</ulink>.
1683 <para>MUD is an embedded software standard defined by the IETF that allows IoT device makers to
1684 advertise device specifications, including the intended communication patterns for their device
1685 when it connects to the network. The network can then use this to author a context-specific
1686 access policy, so the device functions only within those parameters.
</para>
1691 <term><varname>UseHostname=
</varname></term>
1693 <para>When true (the default), the hostname received from
1694 the DHCP server will be set as the transient hostname of the system.
1699 <term><varname>Hostname=
</varname></term>
1701 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's hostname.
1702 Note that the specified hostname must consist only of
7-bit ASCII lower-case characters and
1703 no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1707 <term><varname>UseDomains=
</varname></term>
1709 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
1710 received from the DHCP server will be used as DNS search domain over this link, similar to the effect of
1711 the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name received from
1712 the DHCP server will be used for routing DNS queries only, but not for searching, similar to the effect of
1713 the
<option>Domains=
</option> setting when the argument is prefixed with
<literal>~
</literal>. Defaults to
1716 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
1717 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
1718 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
1719 single-label names.
</para>
1721 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
1722 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1726 <term><varname>UseRoutes=
</varname></term>
1728 <para>When true (the default), the static routes will be requested from the DHCP server and added to the
1729 routing table with a metric of
1024, and a scope of
"global",
"link" or
"host", depending on the route's
1730 destination and gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the
1731 link's own address, the scope will be set to
"host". Otherwise if the gateway is null (a direct route), a
1732 "link" scope will be used. For anything else, scope defaults to
"global".
</para>
1736 <term><varname>UseGateway=
</varname></term>
1738 <para>When true, the gateway will be requested from the DHCP server and added to the routing table with a
1739 metric of
1024, and a scope of
"link". When unset, the value specified with
<option>UseRoutes=
</option>
1744 <term><varname>UseTimezone=
</varname></term>
1745 <listitem><para>When true, the timezone received from the
1746 DHCP server will be set as timezone of the local
1747 system. Defaults to
<literal>no
</literal>.
</para></listitem>
1751 <term><varname>ClientIdentifier=
</varname></term>
1753 <para>The DHCPv4 client identifier to use. Takes one of
<literal>mac
</literal>,
<literal>duid
</literal> or
<literal>duid-only
</literal>.
1754 If set to
<literal>mac
</literal>, the MAC address of the link is used.
1755 If set to
<literal>duid
</literal>, an RFC4361-compliant Client ID, which is the combination of IAID and DUID (see below), is used.
1756 If set to
<literal>duid-only
</literal>, only DUID is used, this may not be RFC compliant, but some setups may require to use this.
1757 Defaults to
<literal>duid
</literal>.
</para>
1762 <term><varname>VendorClassIdentifier=
</varname></term>
1764 <para>The vendor class identifier used to identify vendor
1765 type and configuration.
</para>
1770 <term><varname>UserClass=
</varname></term>
1772 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or applications
1773 it represents. The information contained in this option is a string that represents the user class of which
1774 the client is a member. Each class sets an identifying string of information to be used by the DHCP
1775 service to classify clients. Takes a whitespace-separated list of strings.
</para>
1780 <term><varname>MaxAttempts=
</varname></term>
1782 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
1783 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>. Note that the
1784 time between retries is increased exponentially, up to approximately one per minute, so the
1785 network will not be overloaded even if this number is high. The default is suitable in most
1786 circumstances.
</para>
1791 <term><varname>DUIDType=
</varname></term>
1793 <para>Override the global
<varname>DUIDType
</varname> setting for this network. See
1794 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1795 for a description of possible values.
</para>
1800 <term><varname>DUIDRawData=
</varname></term>
1802 <para>Override the global
<varname>DUIDRawData
</varname> setting for this network. See
1803 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1804 for a description of possible values.
</para>
1809 <term><varname>IAID=
</varname></term>
1811 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned integer.
</para>
1816 <term><varname>RequestBroadcast=
</varname></term>
1818 <para>Request the server to use broadcast messages before
1819 the IP address has been configured. This is necessary for
1820 devices that cannot receive RAW packets, or that cannot
1821 receive packets at all before an IP address has been
1822 configured. On the other hand, this must not be enabled on
1823 networks where broadcasts are filtered out.
</para>
1828 <term><varname>RouteMetric=
</varname></term>
1830 <para>Set the routing metric for routes specified by the DHCP server. Defaults to
1024.
</para>
1835 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1837 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to unset).
1838 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1840 <para>When used in combination with
<varname>VRF=
</varname>, the
1841 VRF's routing table is used when this parameter is not specified.
1847 <term><varname>RouteMTUBytes=
</varname></term>
1849 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further details.
</para>
1854 <term><varname>ListenPort=
</varname></term>
1856 <para>Allow setting custom port for the DHCP client to listen on.
</para>
1861 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
1863 <para>Allows to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease lifetime.
1864 Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal> means that the address
1865 never expires. Defaults to unset.
</para>
1870 <term><varname>SendRelease=
</varname></term>
1872 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops.
1873 Defaults to true.
</para>
1878 <term><varname>SendDecline=
</varname></term>
1880 <para>A boolean. When
<literal>true
</literal>, the DHCPv4 client receives the IP address from the
1881 DHCP server. After a new IP is received, the DHCPv4 client performs IPv4 Duplicate Address
1882 Detection. If duplicate use is detected, the DHCPv4 client rejects the IP by sending a
1883 DHCPDECLINE packet and tries to obtain an IP address again. See
<ulink
1884 url=
"https://tools.ietf.org/html/rfc5227">RFC
5224</ulink>. Defaults to
1885 <literal>unset
</literal>.
</para>
1890 <term><varname>DenyList=
</varname></term>
1892 <para>A whitespace-separated list of IPv4 addresses. DHCP offers from servers in the list are rejected. Note that
1893 if
<varname>AllowList=
</varname> is configured then
<varname>DenyList=
</varname> is ignored.
</para>
1898 <term><varname>AllowList=
</varname></term>
1900 <para>A whitespace-separated list of IPv4 addresses. DHCP offers from servers in the list are accepted.
</para>
1905 <term><varname>RequestOptions=
</varname></term>
1907 <para>Sets request options to be sent to the server in the DHCPv4 request options list. A
1908 whitespace-separated list of integers in the range
1…
254. Defaults to unset.
</para>
1913 <term><varname>SendOption=
</varname></term>
1915 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data type
1916 and data separated with a colon
1917 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1918 The option number must be an integer in the range
1…
254. The type takes one of
1919 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1920 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1921 string may be escaped using
<ulink
1922 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1923 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1924 then all options specified earlier are cleared. Defaults to unset.
</para>
1929 <term><varname>SendVendorOption=
</varname></term>
1931 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data
1932 type and data separated with a colon
1933 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1934 The option number must be an integer in the range
1…
254. The type takes one of
1935 <literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
1936 <literal>ipv4address
</literal>, or
<literal>string
</literal>. Special characters in the data
1937 string may be escaped using
<ulink
1938 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1939 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1940 then all options specified earlier are cleared. Defaults to unset.
</para>
1947 <title>[DHCPv6] Section Options
</title>
1948 <para>The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the
1949 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
</para>
1951 <variablelist class='network-directives'
>
1953 <term><varname>UseAddress=
</varname></term>
1955 <para>When true (the default), the IP addresses provided by the DHCPv6 server will be
1961 <term><varname>UseDNS=
</varname></term>
1962 <term><varname>UseNTP=
</varname></term>
1963 <term><varname>UseHostname=
</varname></term>
1964 <term><varname>UseDomains=
</varname></term>
1966 <para>As in the [DHCPv4] section.
</para>
1971 <term><varname>RouteMetric=
</varname></term>
1973 <para>Set the routing metric for routes specified by the DHCP server. Defaults to
1024.
</para>
1978 <term><varname>RapidCommit=
</varname></term>
1980 <para>Takes a boolean. The DHCPv6 client can obtain configuration parameters from a DHCPv6 server through
1981 a rapid two-message exchange (solicit and reply). When the rapid commit option is enabled by both
1982 the DHCPv6 client and the DHCPv6 server, the two-message exchange is used, rather than the default
1983 four-message exchange (solicit, advertise, request, and reply). The two-message exchange provides
1984 faster client configuration and is beneficial in environments in which networks are under a heavy load.
1985 See
<ulink url=
"https://tools.ietf.org/html/rfc3315#section-17.2.1">RFC
3315</ulink> for details.
1986 Defaults to true.
</para>
1991 <term><varname>MUDURL=
</varname></term>
1993 <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent to
1994 the DHCPv6 server. The syntax and semantics are the same as for
<varname>MUDURL=
</varname> in the
1995 [DHCPv4] section described above.
</para>
2000 <term><varname>RequestOptions=
</varname></term>
2002 <para>When configured, allows to set arbitrary request options in the DHCPv6 request options list
2003 that will be sent to the DHCPv6 server. A whitespace-separated list of integers in the range
2004 1…
254. Defaults to unset.
</para>
2009 <term><varname>SendVendorOption=
</varname></term>
2011 <para>Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier, DHCP
2012 option number, data type, and data separated with a colon (
<literal><replaceable>enterprise
2013 identifier
</replaceable>:
<replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
2014 <replaceable>value
</replaceable></literal>). Enterprise identifier is an unsigned integer in the
2015 range
1–
4294967294. The option number must be an integer in the range
1–
254. Data type takes one
2016 of
<literal>uint8
</literal>,
<literal>uint16
</literal>,
<literal>uint32
</literal>,
2017 <literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2018 <literal>string
</literal>. Special characters in the data string may be escaped using
<ulink
2019 url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2020 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2021 then all options specified earlier are cleared. Defaults to unset.
</para>
2026 <term><varname>ForceDHCPv6PDOtherInformation=
</varname></term>
2028 <para>Takes a boolean that enforces DHCPv6 stateful mode when the 'Other information' bit is set in
2029 Router Advertisement messages. By default setting only the 'O' bit in Router Advertisements
2030 makes DHCPv6 request network information in a stateless manner using a two-message Information
2031 Request and Information Reply message exchange.
2032 <ulink url=
"https://tools.ietf.org/html/rfc7084">RFC
7084</ulink>, requirement WPD-
4, updates
2033 this behavior for a Customer Edge router so that stateful DHCPv6 Prefix Delegation is also
2034 requested when only the 'O' bit is set in Router Advertisements. This option enables such a CE
2035 behavior as it is impossible to automatically distinguish the intention of the 'O' bit otherwise.
2036 By default this option is set to 'false', enable it if no prefixes are delegated when the device
2037 should be acting as a CE router.
</para>
2042 <term><varname>PrefixDelegationHint=
</varname></term>
2044 <para>Takes an IPv6 address with prefix length in the same format as the
2045 <varname>Address=
</varname> in the [Network] section. The DHCPv6 client will include a prefix
2046 hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range
2047 1–
128. Defaults to unset.
</para>
2052 <term><varname>WithoutRA=
</varname></term>
2054 <para>Allows DHCPv6 client to start without router advertisements's managed or other address
2055 configuration flag. Takes one of
<literal>solicit
</literal> or
2056 <literal>information-request
</literal>. Defaults to unset.
</para>
2061 <term><varname>SendOption=
</varname></term>
2063 <para>As in the [DHCPv4] section, however because DHCPv6 uses
16-bit fields to store
2064 option numbers, the option number is an integer in the range
1…
65536.
</para>
2069 <term><varname>UserClass=
</varname></term>
2071 <para>A DHCPv6 client can use User Class option to identify the type or category of user or applications
2072 it represents. The information contained in this option is a string that represents the user class of which
2073 the client is a member. Each class sets an identifying string of information to be used by the DHCP
2074 service to classify clients. Special characters in the data string may be escaped using
2075 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2076 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2077 then all options specified earlier are cleared. Takes a whitespace-separated list of strings. Note that
2078 currently
<constant>NUL
</constant> bytes are not allowed.
</para>
2083 <term><varname>VendorClass=
</varname></term>
2085 <para>A DHCPv6 client can use VendorClass option to identify the vendor that
2086 manufactured the hardware on which the client is running. The information
2087 contained in the data area of this option is contained in one or more opaque
2088 fields that identify details of the hardware configuration. Takes a
2089 whitespace-separated list of strings.
</para>
2096 <title>[DHCPv6PrefixDelegation] Section Options
</title>
2097 <para>The [DHCPv6PrefixDelegation] section configures delegated prefixes assigned by DHCPv6 server.
2098 The settings in this section are used only when
<varname>DHCPv6PrefixDelegation=
</varname> setting
2101 <variablelist class='network-directives'
>
2103 <term><varname>SubnetId=
</varname></term>
2105 <para>Configure a specific subnet ID on the interface from a (previously) received prefix
2106 delegation. You can either set
"auto" (the default) or a specific subnet ID (as defined in
2107 <ulink url=
"https://tools.ietf.org/html/rfc4291#section-2.5.4">RFC
4291</ulink>, section
2108 2.5.4), in which case the allowed value is hexadecimal, from
0 to
0x7fffffffffffffff
2114 <term><varname>Announce=
</varname></term>
2116 <para>Takes a boolean. When enabled, and
<varname>IPv6SendRA=
</varname> in [Network] section
2117 is enabled, the delegated prefixes are distributed through the IPv6 Router Advertisement.
2118 Defaults to yes.
</para>
2123 <term><varname>Assign=
</varname></term>
2125 <para>Takes a boolean. Specifies whether to add an address from the delegated prefixes which
2126 are received from the WAN interface by the DHCPv6 Prefix Delegation. When true (on LAN
2127 interfce), the EUI-
64 algorithm will be used by default to form an interface identifier from
2128 the delegated prefixes. See also
<varname>Token=
</varname> setting below. Defaults to yes.
2134 <term><varname>Token=
</varname></term>
2136 <para>Specifies an optional address generation mode for assigning an address in each
2137 delegated prefix. Takes an IPv6 address. When set, the lower bits of the supplied address is
2138 combined with the upper bits of each delegatad prefix received from the WAN interface by the
2139 DHCPv6 Prefix Delegation to form a complete address. When
<varname>Assign=
</varname> is
2140 disabled, this setting is ignored. When unset, the EUI-
64 algorithm will be used to form
2141 addresses. Defaults to unset.
</para>
2146 <term><varname>ManageTemporaryAddress=
</varname></term>
2148 <para>As in the [Address] section, but defaults to true.
</para>
2155 <title>[IPv6AcceptRA] Section Options
</title>
2156 <para>The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled
2157 with the
<varname>IPv6AcceptRA=
</varname> setting described above:
</para>
2159 <variablelist class='network-directives'
>
2161 <term><varname>UseDNS=
</varname></term>
2163 <para>When true (the default), the DNS servers received in the Router Advertisement will be used.
</para>
2165 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
2166 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2171 <term><varname>UseDomains=
</varname></term>
2173 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
2174 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
2175 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
2176 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
2177 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
2178 <literal>~
</literal>. Defaults to false.
</para>
2180 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
2181 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
2182 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
2183 single-label names.
</para>
2185 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
2186 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
2191 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
2193 <para>The table identifier for the routes received in the Router Advertisement
2194 (a number between
1 and
4294967295, or
0 to unset).
2195 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
2201 <term><varname>UseAutonomousPrefix=
</varname></term>
2203 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
2204 precedence over any statically configured ones.
</para>
2209 <term><varname>UseOnLinkPrefix=
</varname></term>
2211 <para>When true (the default), the onlink prefix received in the Router Advertisement will be
2212 used and takes precedence over any statically configured ones.
</para>
2217 <term><varname>RouterDenyList=
</varname></term>
2219 <para>A whitespace-separated list of IPv6 router addresses. Any information advertised by
2220 the listed router is ignored.
</para>
2225 <term><varname>RouterAllowList=
</varname></term>
2227 <para>A whitespace-separated list of IPv6 router addresses. Only information advertised by
2228 the listed router is accepted. Note that if
<varname>RouterAllowList=
</varname> is
2229 configured then
<varname>RouterDenyList=
</varname> is ignored.
</para>
2234 <term><varname>PrefixDenyList=
</varname></term>
2236 <para>A whitespace-separated list of IPv6 prefixes. IPv6 prefixes supplied via router
2237 advertisements in the list are ignored.
</para>
2242 <term><varname>PrefixAllowList=
</varname></term>
2244 <para>A whitespace-separated list of IPv6 prefixes. IPv6 prefixes supplied via router
2245 advertisements in the list are allowed. Note that if
<varname>PrefixAllowList=
</varname> is
2246 configured then
<varname>PrefixDenyList=
</varname> is ignored.
</para>
2251 <term><varname>RouteDenyList=
</varname></term>
2253 <para>A whitespace-separated list of IPv6 route prefixes. IPv6 route prefixes supplied via
2254 router advertisements in the list are ignored.
</para>
2259 <term><varname>RouteAllowList=
</varname></term>
2261 <para>A whitespace-separated list of IPv6 route prefixes. IPv6 route prefixes supplied via
2262 router advertisements in the list are allowed. Note that if
<varname>RouteAllowList=
</varname> is
2263 configured then
<varname>RouteDenyList=
</varname> is ignored.
</para>
2268 <term><varname>DHCPv6Client=
</varname></term>
2270 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true or
2271 <literal>always
</literal>, the DHCPv6 client will be started when the RA has the managed or
2272 other information flag. If set to
<literal>always
</literal>, the DHCPv6 client will also be
2273 started in managed mode when neither managed nor other information flag is set in the RA.
2274 Defaults to true.
</para>
2281 <title>[DHCPServer] Section Options
</title>
2282 <para>The [DHCPServer] section contains settings for the DHCP server, if enabled via the
2283 <varname>DHCPServer=
</varname> option described above:
</para>
2285 <variablelist class='network-directives'
>
2288 <term><varname>PoolOffset=
</varname></term>
2289 <term><varname>PoolSize=
</varname></term>
2291 <listitem><para>Configures the pool of addresses to hand out. The pool
2292 is a contiguous sequence of IP addresses in the subnet configured for
2293 the server address, which does not include the subnet nor the broadcast
2294 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
2295 from the start of subnet, or zero to use the default value.
2296 <varname>PoolSize=
</varname> takes the number of IP addresses in the
2297 pool or zero to use the default value. By default, the pool starts at
2298 the first address after the subnet address and takes up the rest of
2299 the subnet, excluding the broadcast address. If the pool includes
2300 the server address (the default), this is reserved and not handed
2301 out to clients.
</para></listitem>
2305 <term><varname>DefaultLeaseTimeSec=
</varname></term>
2306 <term><varname>MaxLeaseTimeSec=
</varname></term>
2308 <listitem><para>Control the default and maximum DHCP lease
2309 time to pass to clients. These settings take time values in seconds or
2310 another common time unit, depending on the suffix. The default
2311 lease time is used for clients that did not ask for a specific
2312 lease time. If a client asks for a lease time longer than the
2313 maximum lease time, it is automatically shortened to the
2314 specified time. The default lease time defaults to
1h, the
2315 maximum lease time to
12h. Shorter lease times are beneficial
2316 if the configuration data in DHCP leases changes frequently
2317 and clients shall learn the new settings with shorter
2318 latencies. Longer lease times reduce the generated DHCP
2319 network traffic.
</para></listitem>
2323 <term><varname>EmitDNS=
</varname></term>
2324 <term><varname>DNS=
</varname></term>
2326 <listitem><para><varname>EmitDNS=
</varname> takes a boolean. Configures whether the DHCP leases
2327 handed out to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>. The
2328 DNS servers to pass to clients may be configured with the
<varname>DNS=
</varname> option, which takes
2329 a list of IPv4 addresses. If the
<varname>EmitDNS=
</varname> option is enabled but no servers
2330 configured, the servers are automatically propagated from an
"uplink" interface that has appropriate
2331 servers set. The
"uplink" interface is determined by the default route of the system with the highest
2332 priority. Note that this information is acquired at the time the lease is handed out, and does not
2333 take uplink interfaces into account that acquire DNS server information at a later point. If no
2334 suitable uplink interface is found the DNS server data from
<filename>/etc/resolv.conf
</filename> is
2335 used. Also, note that the leases are not refreshed if the uplink network configuration changes. To
2336 ensure clients regularly acquire the most current uplink DNS server information, it is thus advisable
2337 to shorten the DHCP lease time via
<varname>MaxLeaseTimeSec=
</varname> described
2338 above.
</para></listitem>
2342 <term><varname>EmitNTP=
</varname></term>
2343 <term><varname>NTP=
</varname></term>
2344 <term><varname>EmitSIP=
</varname></term>
2345 <term><varname>SIP=
</varname></term>
2346 <term><varname>EmitPOP3=
</varname></term>
2347 <term><varname>POP3=
</varname></term>
2348 <term><varname>EmitSMTP=
</varname></term>
2349 <term><varname>SMTP=
</varname></term>
2350 <term><varname>EmitLPR=
</varname></term>
2351 <term><varname>LPR=
</varname></term>
2353 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname> settings
2354 described above, these settings configure whether and what server information for the indicate
2355 protocol shall be emitted as part of the DHCP lease. The same syntax, propagation semantics and
2356 defaults apply as for
<varname>EmitDNS=
</varname> and
<varname>DNS=
</varname>.
</para></listitem>
2360 <term><varname>EmitRouter=
</varname></term>
2362 <listitem><para>Similar to the
<varname>EmitDNS=
</varname>
2363 setting described above, this setting configures whether the
2364 DHCP lease should contain the router option. The same syntax,
2365 propagation semantics and defaults apply as for
2366 <varname>EmitDNS=
</varname>.
</para></listitem>
2370 <term><varname>EmitTimezone=
</varname></term>
2371 <term><varname>Timezone=
</varname></term>
2373 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2374 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2375 <varname>Timezone=
</varname> setting takes a timezone string
2376 (such as
<literal>Europe/Berlin
</literal> or
2377 <literal>UTC
</literal>) to pass to clients. If no explicit
2378 timezone is set, the system timezone of the local host is
2379 propagated, as determined by the
2380 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2384 <term><varname>SendOption=
</varname></term>
2386 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2387 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2388 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2389 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2390 <literal>string
</literal>. Special characters in the data string may be escaped using
2391 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2392 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2393 then all options specified earlier are cleared. Defaults to unset.
</para>
2398 <term><varname>SendVendorOption=
</varname></term>
2400 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2401 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2402 The option number is an integer in the range
1…
254. The type takes one of
<literal>uint8
</literal>,
2403 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2404 <literal>string
</literal>. Special characters in the data string may be escaped using
2405 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2406 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2407 then all options specified earlier are cleared. Defaults to unset.
</para>
2415 <title>[IPv6SendRA] Section Options
</title>
2416 <para>The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether
2417 to act as a router, if enabled via the
<varname>IPv6SendRA=
</varname> option described above. IPv6
2418 network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections.
2421 <variablelist class='network-directives'
>
2424 <term><varname>Managed=
</varname></term>
2425 <term><varname>OtherInformation=
</varname></term>
2427 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2428 addresses on the network link when
<varname>Managed=
</varname>
2429 is set to
<literal>true
</literal> or if only additional network
2430 information can be obtained via DHCPv6 for the network link when
2431 <varname>OtherInformation=
</varname> is set to
2432 <literal>true
</literal>. Both settings default to
2433 <literal>false
</literal>, which means that a DHCPv6 server is not being
2434 used.
</para></listitem>
2438 <term><varname>RouterLifetimeSec=
</varname></term>
2440 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. When set to
2441 0, the host is not acting as a router. Defaults to
30 minutes.
</para>
2446 <term><varname>RouterPreference=
</varname></term>
2448 <listitem><para>Configures IPv6 router preference if
2449 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2450 <literal>high
</literal>,
<literal>medium
</literal> and
2451 <literal>low
</literal>, with
<literal>normal
</literal> and
2452 <literal>default
</literal> added as synonyms for
2453 <literal>medium
</literal> just to make configuration easier. See
2454 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2455 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2459 <term><varname>EmitDNS=
</varname></term>
2460 <term><varname>DNS=
</varname></term>
2462 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses that
2463 are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is
2464 true.
<varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that case
2465 the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS servers are read
2466 from the [Network] section. If the [Network] section does not contain any DNS servers either, DNS
2467 servers from the uplink with the highest priority default route are used. When
2468 <varname>EmitDNS=
</varname> is false, no DNS server information is sent in Router Advertisement
2469 messages.
<varname>EmitDNS=
</varname> defaults to true.
</para></listitem>
2473 <term><varname>EmitDomains=
</varname></term>
2474 <term><varname>Domains=
</varname></term>
2476 <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when
2477 <varname>EmitDomains=
</varname> is true. If
<varname>Domains=
</varname> is empty, DNS search domains
2478 are read from the [Network] section. If the [Network] section does not contain any DNS search domains
2479 either, DNS search domains from the uplink with the highest priority default route are used. When
2480 <varname>EmitDomains=
</varname> is false, no DNS search domain information is sent in Router
2481 Advertisement messages.
<varname>EmitDomains=
</varname> defaults to true.
</para></listitem>
2485 <term><varname>DNSLifetimeSec=
</varname></term>
2487 <listitem><para>Lifetime in seconds for the DNS server addresses listed
2488 in
<varname>DNS=
</varname> and search domains listed in
2489 <varname>Domains=
</varname>.
</para></listitem>
2496 <title>[IPv6Prefix] Section Options
</title>
2497 <para>One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router
2498 Advertisements. See
<ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink> for further
2501 <variablelist class='network-directives'
>
2504 <term><varname>AddressAutoconfiguration=
</varname></term>
2505 <term><varname>OnLink=
</varname></term>
2507 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2508 autoconfigured with this prefix and whether the prefix can be used for
2509 onlink determination. Both settings default to
<literal>true
</literal>
2510 in order to ease configuration.
2515 <term><varname>Prefix=
</varname></term>
2517 <listitem><para>The IPv6 prefix that is to be distributed to hosts. Similarly to configuring static
2518 IPv6 addresses, the setting is configured as an IPv6 prefix and its prefix length, separated by a
2519 <literal>/
</literal> character. Use multiple [IPv6Prefix] sections to configure multiple IPv6
2520 prefixes since prefix lifetimes, address autoconfiguration and onlink status may differ from one
2521 prefix to another.
</para></listitem>
2525 <term><varname>PreferredLifetimeSec=
</varname></term>
2526 <term><varname>ValidLifetimeSec=
</varname></term>
2528 <listitem><para>Preferred and valid lifetimes for the prefix measured in
2529 seconds.
<varname>PreferredLifetimeSec=
</varname> defaults to
604800
2530 seconds (one week) and
<varname>ValidLifetimeSec=
</varname> defaults
2531 to
2592000 seconds (
30 days).
</para></listitem>
2535 <term><varname>Assign=
</varname></term>
2536 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2543 <title>[IPv6RoutePrefix] Section Options
</title>
2544 <para>One or more [IPv6RoutePrefix] sections contain the IPv6
2545 prefix routes that are announced via Router Advertisements. See
2546 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2547 for further details.
</para>
2549 <variablelist class='network-directives'
>
2552 <term><varname>Route=
</varname></term>
2554 <listitem><para>The IPv6 route that is to be distributed to hosts. Similarly to configuring static
2555 IPv6 routes, the setting is configured as an IPv6 prefix routes and its prefix route length,
2556 separated by a
<literal>/
</literal> character. Use multiple [IPv6PrefixRoutes] sections to configure
2557 multiple IPv6 prefix routes.
</para></listitem>
2561 <term><varname>LifetimeSec=
</varname></term>
2563 <listitem><para>Lifetime for the route prefix measured in
2564 seconds.
<varname>LifetimeSec=
</varname> defaults to
604800 seconds (one week).
2572 <title>[Bridge] Section Options
</title>
2573 <para>The [Bridge] section accepts the following keys:
</para>
2574 <variablelist class='network-directives'
>
2576 <term><varname>UnicastFlood=
</varname></term>
2578 <para>Takes a boolean. Controls whether the bridge should flood
2579 traffic for which an FDB entry is missing and the destination
2580 is unknown through this port. When unset, the kernel's default will be used.
2585 <term><varname>MulticastFlood=
</varname></term>
2587 <para>Takes a boolean. Controls whether the bridge should flood
2588 traffic for which an MDB entry is missing and the destination
2589 is unknown through this port. When unset, the kernel's default will be used.
2594 <term><varname>MulticastToUnicast=
</varname></term>
2596 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
2597 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
2598 When unset, the kernel's default will be used.
2603 <term><varname>NeighborSuppression=
</varname></term>
2605 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
2606 this port. When unset, the kernel's default will be used.
2611 <term><varname>Learning=
</varname></term>
2613 <para>Takes a boolean. Configures whether MAC address learning is enabled for
2614 this port. When unset, the kernel's default will be used.
2619 <term><varname>HairPin=
</varname></term>
2621 <para>Takes a boolean. Configures whether traffic may be sent back out of the port on which it
2622 was received. When this flag is false, then the bridge will not forward traffic back out of the
2623 receiving port. When unset, the kernel's default will be used.
</para>
2627 <term><varname>UseBPDU=
</varname></term>
2629 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
2630 processed by the bridge port. When unset, the kernel's default will be used.
</para>
2634 <term><varname>FastLeave=
</varname></term>
2636 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
2637 traffic on a port that receives an IGMP Leave message. It is only used with
2638 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
2642 <term><varname>AllowPortToBeRoot=
</varname></term>
2644 <para>Takes a boolean. Configures whether a given port is allowed to
2645 become a root port. Only used when STP is enabled on the bridge.
2646 When unset, the kernel's default will be used.
</para>
2650 <term><varname>ProxyARP=
</varname></term>
2652 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
2653 When unset, the kernel's default will be used.
</para>
2657 <term><varname>ProxyARPWiFi=
</varname></term>
2659 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
2660 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
2661 When unset, the kernel's default will be used.
</para>
2665 <term><varname>MulticastRouter=
</varname></term>
2667 <para>Configures this port for having multicast routers attached. A port with a multicast
2668 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
2669 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
2670 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
2671 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
2672 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
2676 <term><varname>Cost=
</varname></term>
2678 <para>Sets the
"cost" of sending packets of this interface.
2679 Each port in a bridge may have a different speed and the cost
2680 is used to decide which link to use. Faster interfaces
2681 should have lower costs. It is an integer value between
1 and
2686 <term><varname>Priority=
</varname></term>
2688 <para>Sets the
"priority" of sending packets on this interface.
2689 Each port in a bridge may have a different priority which is used
2690 to decide which link to use. Lower value means higher priority.
2691 It is an integer value between
0 to
63. Networkd does not set any
2692 default, meaning the kernel default value of
32 is used.
</para>
2698 <title>[BridgeFDB] Section Options
</title>
2699 <para>The [BridgeFDB] section manages the forwarding database table of a port and accepts the following
2700 keys. Specify several [BridgeFDB] sections to configure several static MAC table entries.
</para>
2702 <variablelist class='network-directives'
>
2704 <term><varname>MACAddress=
</varname></term>
2706 <para>As in the [Network] section. This key is mandatory.
</para>
2710 <term><varname>Destination=
</varname></term>
2712 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
2716 <term><varname>VLANId=
</varname></term>
2718 <para>The VLAN ID for the new static MAC table entry. If
2719 omitted, no VLAN ID information is appended to the new static MAC
2724 <term><varname>VNI=
</varname></term>
2726 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
2727 the remote VXLAN tunnel endpoint. Takes a number in the range
1…
16777215.
2728 Defaults to unset.
</para>
2732 <term><varname>AssociatedWith=
</varname></term>
2734 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
2735 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
2736 <literal>use
</literal> means the address is in use. User space can use this option to
2737 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
2738 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
2739 means the address is associated with master devices fdb.
<literal>router
</literal> means
2740 the destination address is associated with a router. Note that it's valid if the referenced
2741 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
2747 <title>[BridgeMDB] Section Options
</title>
2748 <para>The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following
2749 keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.
</para>
2751 <variablelist class='network-directives'
>
2753 <term><varname>MulticastGroupAddress=
</varname></term>
2755 <para>Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.
</para>
2759 <term><varname>VLANId=
</varname></term>
2761 <para>The VLAN ID for the new entry. Valid ranges are
0 (no VLAN) to
4094. Optional, defaults to
0.
</para>
2768 <title>[LLDP] Section Options
</title>
2769 <para>The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following
2771 <variablelist class='network-directives'
>
2773 <term><varname>MUDURL=
</varname></term>
2775 <para>When configured, the specified Manufacturer Usage Descriptions (MUD) URL will be sent in
2776 LLDP packets. The syntax and semantics are the same as for
<varname>MUDURL=
</varname> in the
2777 [DHCPv4] section described above.
</para>
2779 <para>The MUD URLs received via LLDP packets are saved and can be read using the
2780 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
2787 <title>[CAN] Section Options
</title>
2788 <para>The [CAN] section manages the Controller Area Network (CAN bus) and accepts the
2789 following keys:
</para>
2790 <variablelist class='network-directives'
>
2792 <term><varname>BitRate=
</varname></term>
2794 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
2795 be used here. Takes a number in the range
1…
4294967295.
</para>
2799 <term><varname>SamplePoint=
</varname></term>
2801 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
2802 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>).
</para>
2806 <term><varname>DataBitRate=
</varname></term>
2807 <term><varname>DataSamplePoint=
</varname></term>
2809 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
2810 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
2814 <term><varname>FDMode=
</varname></term>
2816 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
2817 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
2818 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys.
</para>
2822 <term><varname>FDNonISO=
</varname></term>
2824 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
2825 interface. When unset, the kernel's default will be used.
</para>
2829 <term><varname>RestartSec=
</varname></term>
2831 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
2832 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
2833 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
2834 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
2835 automatic restart off. By default automatic restart is disabled.
</para>
2839 <term><varname>Termination=
</varname></term>
2841 <para>Takes a boolean. When
<literal>yes
</literal>, the termination resistor will be selected for
2842 the bias network. When unset, the kernel's default will be used.
</para>
2846 <term><varname>TripleSampling=
</varname></term>
2848 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
2849 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
2853 <term><varname>BusErrorReporting=
</varname></term>
2855 <para>Takes a boolean. When
<literal>yes
</literal>, reporting of CAN bus errors is activated
2856 (those include single bit, frame format, and bit stuffing errors, unable to send dominant bit,
2857 unable to send recessive bit, bus overload, active error announcement, error occurred on
2858 transmission). When unset, the kernel's default will be used. Note: in case of a CAN bus with a
2859 single CAN device, sending a CAN frame may result in a huge number of CAN bus errors.
</para>
2863 <term><varname>ListenOnly=
</varname></term>
2865 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
2866 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
2867 bit. Listen-only mode is important to debug CAN networks without interfering with the
2868 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
2876 <title>[QDisc] Section Options
</title>
2877 <para>The [QDisc] section manages the traffic control queueing discipline (qdisc).
</para>
2879 <variablelist class='network-directives'
>
2881 <term><varname>Parent=
</varname></term>
2883 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
2884 or
<literal>ingress
</literal>. This is mandatory.
</para>
2888 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2893 <title>[NetworkEmulator] Section Options
</title>
2894 <para>The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It
2895 can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP
2896 applications, or limit the bandwidth usage of a particular service to simulate internet connections.
2899 <variablelist class='network-directives'
>
2900 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2901 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2904 <term><varname>DelaySec=
</varname></term>
2906 <para>Specifies the fixed amount of delay to be added to all packets going out of the
2907 interface. Defaults to unset.
</para>
2912 <term><varname>DelayJitterSec=
</varname></term>
2914 <para>Specifies the chosen delay to be added to the packets outgoing to the network
2915 interface. Defaults to unset.
</para>
2920 <term><varname>PacketLimit=
</varname></term>
2922 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
2923 An unsigned integer in the range
0–
4294967294. Defaults to
1000.
</para>
2928 <term><varname>LossRate=
</varname></term>
2930 <para>Specifies an independent loss probability to be added to the packets outgoing from the
2931 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
2936 <term><varname>DuplicateRate=
</varname></term>
2938 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
2939 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
2946 <title>[TokenBucketFilter] Section Options
</title>
2947 <para>The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter
2950 <variablelist class='network-directives'
>
2951 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2952 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2955 <term><varname>LatencySec=
</varname></term>
2957 <para>Specifies the latency parameter, which specifies the maximum amount of time a
2958 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
2963 <term><varname>LimitBytes=
</varname></term>
2965 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
2966 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
2967 respectively, to the base of
1024. Defaults to unset.
</para>
2972 <term><varname>BurstBytes=
</varname></term>
2974 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
2975 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
2976 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to
2982 <term><varname>Rate=
</varname></term>
2984 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
2985 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
2986 Defaults to unset.
</para>
2991 <term><varname>MPUBytes=
</varname></term>
2993 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
2994 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
2995 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to zero.
</para>
3000 <term><varname>PeakRate=
</varname></term>
3002 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
3003 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3004 1000. Defaults to unset.
</para>
3009 <term><varname>MTUBytes=
</varname></term>
3011 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
3012 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
3013 Defaults to unset.
</para>
3020 <title>[PIE] Section Options
</title>
3021 <para>The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral
3022 controller-Enhanced (PIE).
</para>
3024 <variablelist class='network-directives'
>
3025 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3026 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3029 <term><varname>PacketLimit=
</varname></term>
3031 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3032 incoming packets are dropped. An unsigned integer in the range
1…
4294967294. Defaults to unset and
3033 kernel's default is used.
</para>
3040 <title>[FlowQueuePIE] Section Options
</title>
3041 <para>The
<literal>[FlowQueuePIE]
</literal> section manages the queueing discipline
3042 (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).
</para>
3044 <variablelist class='network-directives'
>
3045 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3046 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3049 <term><varname>PacketLimit=
</varname></term>
3051 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3052 incoming packets are dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and
3053 kernel's default is used.
</para>
3060 <title>[StochasticFairBlue] Section Options
</title>
3061 <para>The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue
3064 <variablelist class='network-directives'
>
3065 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3066 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3069 <term><varname>PacketLimit=
</varname></term>
3071 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3072 incoming packets are dropped. An unsigned integer in the range
0–
4294967294. Defaults to unset and
3073 kernel's default is used.
</para>
3080 <title>[StochasticFairnessQueueing] Section Options
</title>
3081 <para>The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic
3082 fairness queueing (sfq).
</para>
3084 <variablelist class='network-directives'
>
3085 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3086 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3089 <term><varname>PerturbPeriodSec=
</varname></term>
3091 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
3098 <title>[BFIFO] Section Options
</title>
3099 <para>The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First
3102 <variablelist class='network-directives'
>
3103 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3104 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3107 <term><varname>LimitBytes=
</varname></term>
3109 <para>Specifies the hard limit in bytes on the FIFO buffer size. The size limit prevents overflow
3110 in case the kernel is unable to dequeue packets as quickly as it receives them. When this limit is
3111 reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed
3112 as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3113 kernel default is used.
</para>
3120 <title>[PFIFO] Section Options
</title>
3121 <para>The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out
3124 <variablelist class='network-directives'
>
3125 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3126 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3129 <term><varname>PacketLimit=
</varname></term>
3131 <para>Specifies the hard limit on the number of packets in the FIFO queue. The size limit prevents
3132 overflow in case the kernel is unable to dequeue packets as quickly as it receives them. When this
3133 limit is reached, incoming packets are dropped. An unsigned integer in the range
3134 0–
4294967294. Defaults to unset and kernel's default is used.
</para>
3141 <title>[PFIFOHeadDrop] Section Options
</title>
3142 <para>The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out
3143 Head Drop (pfifo_head_drop).
</para>
3145 <variablelist class='network-directives'
>
3146 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3147 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3150 <term><varname>PacketLimit=
</varname></term>
3152 <para>As in [PFIFO] section.
</para></listitem>
3158 <title>[PFIFOFast] Section Options
</title>
3159 <para>The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast
3160 (pfifo_fast).
</para>
3162 <variablelist class='network-directives'
>
3163 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3164 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3169 <title>[CAKE] Section Options
</title>
3170 <para>The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced
3173 <variablelist class='network-directives'
>
3174 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3175 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3178 <term><varname>OverheadBytes=
</varname></term>
3180 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative. Takes
3181 an integer in the range from -
64 to
256. Defaults to unset and kernel's default is used.
</para>
3186 <term><varname>Bandwidth=
</varname></term>
3188 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
3189 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
3190 unset and kernel's default is used.
</para>
3197 <title>[ControlledDelay] Section Options
</title>
3198 <para>The [ControlledDelay] section manages the queueing discipline (qdisc) of
3199 controlled delay (CoDel).
</para>
3201 <variablelist class='network-directives'
>
3202 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3203 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3206 <term><varname>PacketLimit=
</varname></term>
3208 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3209 incoming packets are dropped. An unsigned integer in the range
0–
4294967294. Defaults to unset and
3210 kernel's default is used.
</para>
3215 <term><varname>TargetSec=
</varname></term>
3217 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3218 Defaults to unset and kernel's default is used.
</para>
3223 <term><varname>IntervalSec=
</varname></term>
3225 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3226 become too stale. Defaults to unset and kernel's default is used.
</para>
3231 <term><varname>ECN=
</varname></term>
3233 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3234 unset and kernel's default is used.
</para>
3239 <term><varname>CEThresholdSec=
</varname></term>
3241 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3242 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3249 <title>[DeficitRoundRobinScheduler] Section Options
</title>
3250 <para>The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round
3251 Robin Scheduler (DRR).
</para>
3253 <variablelist class='network-directives'
>
3254 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3255 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3260 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
3261 <para>The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round
3262 Robin Scheduler (DRR).
</para>
3264 <variablelist class='network-directives'
>
3265 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3266 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3269 <term><varname>QuantumBytes=
</varname></term>
3271 <para>Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves
3272 to the next class. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3273 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to the MTU of the
3282 <title>[EnhancedTransmissionSelection] Section Options
</title>
3283 <para>The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced
3284 Transmission Selection (ETS).
</para>
3286 <variablelist class='network-directives'
>
3287 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3288 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3291 <term><varname>Bands=
</varname></term>
3293 <para>Specifies the number of bands. An unsigned integer in the range
1–
16. This value has to be at
3294 least large enough to cover the strict bands specified through the
<varname>StrictBands=
</varname>
3295 and bandwidth-sharing bands specified in
<varname>QuantumBytes=
</varname>.
</para>
3300 <term><varname>StrictBands=
</varname></term>
3302 <para>Specifies the number of bands that should be created in strict mode. An unsigned integer in
3303 the range
1–
16.
</para>
3308 <term><varname>QuantumBytes=
</varname></term>
3310 <para>Specifies the white-space separated list of quantum used in band-sharing bands. When
3311 suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3312 respectively, to the base of
1024. This setting can be specified multiple times. If an empty
3313 string is assigned, then the all previous assignments are cleared.
</para>
3318 <term><varname>PriorityMap=
</varname></term>
3320 <para>The priority map maps the priority of a packet to a band. The argument is a whitespace
3321 separated list of numbers. The first number indicates which band the packets with priority
0 should
3322 be put to, the second is for priority
1, and so on. There can be up to
16 numbers in the list. If
3323 there are fewer, the default band that traffic with one of the unmentioned priorities goes to is
3324 the last one. Each band number must be in the range
0…
255. This setting can be specified multiple
3325 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
3332 <title>[GenericRandomEarlyDetection] Section Options
</title>
3333 <para>The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random
3334 Early Detection (GRED).
</para>
3336 <variablelist class='network-directives'
>
3337 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3338 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3341 <term><varname>VirtualQueues=
</varname></term>
3343 <para>Specifies the number of virtual queues. Takes a integer in the range
1…
16. Defaults to unset
3344 and kernel's default is used.
</para>
3349 <term><varname>DefaultVirtualQueue=
</varname></term>
3351 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
3352 Defaults to unset and kernel's default is used.
</para>
3357 <term><varname>GenericRIO=
</varname></term>
3359 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
3360 unset and kernel's default is used.
</para>
3367 <title>[FairQueueingControlledDelay] Section Options
</title>
3368 <para>The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing
3369 controlled delay (FQ-CoDel).
</para>
3371 <variablelist class='network-directives'
>
3372 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3373 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3376 <term><varname>PacketLimit=
</varname></term>
3378 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
3379 dropped. Defaults to unset and kernel's default is used.
</para>
3384 <term><varname>MemoryLimitBytes=
</varname></term>
3386 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
3387 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3388 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
3393 <term><varname>Flows=
</varname></term>
3395 <para>Specifies the number of flows into which the incoming packets are classified.
3396 Defaults to unset and kernel's default is used.
</para>
3401 <term><varname>TargetSec=
</varname></term>
3403 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
3404 Defaults to unset and kernel's default is used.
</para>
3409 <term><varname>IntervalSec=
</varname></term>
3411 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
3412 become too stale. Defaults to unset and kernel's default is used.
</para>
3417 <term><varname>QuantumBytes=
</varname></term>
3419 <para>Specifies the number of bytes used as the
"deficit" in the fair queuing algorithm timespan.
3420 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3421 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
3426 <term><varname>ECN=
</varname></term>
3428 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3429 unset and kernel's default is used.
</para>
3434 <term><varname>CEThresholdSec=
</varname></term>
3436 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3437 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3444 <title>[FairQueueing] Section Options
</title>
3445 <para>The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing
3448 <variablelist class='network-directives'
>
3449 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3450 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3453 <term><varname>PacketLimit=
</varname></term>
3455 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
3456 dropped. Defaults to unset and kernel's default is used.
</para>
3461 <term><varname>FlowLimit=
</varname></term>
3463 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
3464 unset and kernel's default is used.
</para>
3469 <term><varname>QuantumBytes=
</varname></term>
3471 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
3472 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3473 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
3474 default is used.
</para>
3479 <term><varname>InitialQuantumBytes=
</varname></term>
3481 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
3482 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
3483 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3484 kernel's default is used.
</para>
3489 <term><varname>MaximumRate=
</varname></term>
3491 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
3492 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3493 1000. Defaults to unset and kernel's default is used.
</para>
3498 <term><varname>Buckets=
</varname></term>
3500 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
3501 kernel's default is used.
</para>
3506 <term><varname>OrphanMask=
</varname></term>
3508 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
3509 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
3510 kernel's default is used.
</para>
3515 <term><varname>Pacing=
</varname></term>
3517 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
3518 default is used.
</para>
3523 <term><varname>CEThresholdSec=
</varname></term>
3525 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3526 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3533 <title>[TrivialLinkEqualizer] Section Options
</title>
3534 <para>The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link
3535 equalizer (teql).
</para>
3537 <variablelist class='network-directives'
>
3538 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3539 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3542 <term><varname>Id=
</varname></term>
3544 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
3545 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
3546 <constant>max_equalizers=N+
1</constant> option must be loaded before
3547 <command>systemd-networkd
</command> is started.
</para>
3554 <title>[HierarchyTokenBucket] Section Options
</title>
3555 <para>The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token
3556 bucket (htb).
</para>
3558 <variablelist class='network-directives'
>
3559 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3560 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3563 <term><varname>DefaultClass=
</varname></term>
3565 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
3566 to the class. Defaults to unset.
</para>
3571 <term><varname>RateToQuantum=
</varname></term>
3573 <para>Takes an unsigned integer. The DRR quantums are calculated by dividing the value
3574 configured in
<varname>Rate=
</varname> by
<varname>RateToQuantum=
</varname>.
</para>
3581 <title>[HierarchyTokenBucketClass] Section Options
</title>
3582 <para>The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket
3585 <variablelist class='network-directives'
>
3586 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3587 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3590 <term><varname>Priority=
</varname></term>
3592 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
3593 priority field are tried for packets first.
</para>
3598 <term><varname>QuantumBytes=
</varname></term>
3600 <para>Specifies how many bytes to serve from leaf at once. When suffixed with K, M, or G, the
3601 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
3607 <term><varname>MTUBytes=
</varname></term>
3609 <para>Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified
3610 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
3615 <term><varname>OverheadBytes=
</varname></term>
3617 <para>Takes an unsigned integer which specifies per-packet size overhead used in rate
3618 computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3619 Megabytes, or Gigabytes, respectively, to the base of
1024.
</para>
3624 <term><varname>Rate=
</varname></term>
3626 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
3627 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
3628 to the base of
1000. This setting is mandatory.
</para>
3633 <term><varname>CeilRate=
</varname></term>
3635 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
3636 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
3637 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
3643 <term><varname>BufferBytes=
</varname></term>
3645 <para>Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed
3646 with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively,
3647 to the base of
1024.
</para>
3652 <term><varname>CeilBufferBytes=
</varname></term>
3654 <para>Specifies the maximum bytes burst for ceil which can be accumulated during idle period.
3655 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3656 respectively, to the base of
1024.
</para>
3663 <title>[HeavyHitterFilter] Section Options
</title>
3664 <para>The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter
3667 <variablelist class='network-directives'
>
3668 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3669 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3672 <term><varname>PacketLimit=
</varname></term>
3674 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached,
3675 incoming packets are dropped. An unsigned integer in the range
0–
4294967294. Defaults to unset and
3676 kernel's default is used.
</para>
3683 <title>[QuickFairQueueing] Section Options
</title>
3684 <para>The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing
3687 <variablelist class='network-directives'
>
3688 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3689 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3694 <title>[QuickFairQueueingClass] Section Options
</title>
3695 <para>The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing
3698 <variablelist class='network-directives'
>
3699 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3700 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3703 <term><varname>Weight=
</varname></term>
3705 <para>Specifies the weight of the class. Takes an integer in the range
1…
1023. Defaults to
3706 unset in which case the kernel default is used.
</para>
3711 <term><varname>MaxPacketBytes=
</varname></term>
3713 <para>Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the
3714 specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
3715 1024. When unset, the kernel default is used.
</para>
3722 <title>[BridgeVLAN] Section Options
</title>
3723 <para>The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the
3724 following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The
3725 <varname>VLANFiltering=
</varname> option has to be enabled, see the [Bridge] section in
3726 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
3728 <variablelist class='network-directives'
>
3730 <term><varname>VLAN=
</varname></term>
3732 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. VLAN IDs are valid
3733 from
1 to
4094.
</para>
3737 <term><varname>EgressUntagged=
</varname></term>
3739 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
3740 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
3741 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
3745 <term><varname>PVID=
</varname></term>
3747 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
3748 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
3749 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
3756 <title>Examples
</title>
3758 <title>Static network configuration
</title>
3760 <programlisting># /etc/systemd/network/
50-static.network
3765 Address=
192.168.0.15/
24
3766 Gateway=
192.168.0.1</programlisting>
3768 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
3769 specified gateway will be used for a default route.
</para>
3773 <title>DHCP on ethernet links
</title>
3775 <programlisting># /etc/systemd/network/
80-dhcp.network
3780 DHCP=yes
</programlisting>
3782 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
3783 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
3787 <title>IPv6 Prefix Delegation
</title>
3789 <programlisting># /etc/systemd/network/
55-ipv6-pd-upstream.network
3794 DHCP=ipv6
</programlisting>
3796 <programlisting># /etc/systemd/network/
56-ipv6-pd-downstream.network
3802 DHCPv6PrefixDelegation=yes
</programlisting>
3804 <para>This will enable DHCPv6-PD on the interface enp1s0 as an upstream interface where the
3805 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
3806 The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network.
3811 <title>A bridge with two enslaved links
</title>
3813 <programlisting># /etc/systemd/network/
25-bridge-static.network
3818 Address=
192.168.0.15/
24
3820 DNS=
192.168.0.1</programlisting>
3822 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
3827 Bridge=bridge0
</programlisting>
3829 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
3834 Bridge=bridge0
</programlisting>
3836 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
3837 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
3838 and network assigned, and a default route via the specified gateway will be
3839 added. The specified DNS server will be added to the global list of DNS resolvers.
3847 # /etc/systemd/network/
20-bridge-slave-interface-vlan.network
3863 EgressUntagged=
300-
400</programlisting>
3865 <para>This overrides the configuration specified in the previous example for the
3866 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
3867 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
3868 untagged when they leave on this interface. Untagged packets which arrive on this
3869 interface will be assigned VLAN ID
42.
</para>
3873 <title>Various tunnels
</title>
3875 <programlisting>/etc/systemd/network/
25-tunnels.network
3886 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
3892 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
3898 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
3904 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
3910 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
3911 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
3915 <title>A bond device
</title>
3917 <programlisting># /etc/systemd/network/
30-bond1.network
3925 <programlisting># /etc/systemd/network/
30-bond1.netdev
3931 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
3933 MACAddress=
52:
54:
00:e9:
64:
41
3939 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
3941 MACAddress=
52:
54:
00:e9:
64:
42
3947 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
3948 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
3949 will be used to acquire an address.
</para>
3953 <title>Virtual Routing and Forwarding (VRF)
</title>
3954 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
3955 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
3956 within the routing table defined during VRF creation. For kernels before
4.8 traffic
3957 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
3959 <programlisting># /etc/systemd/network/
25-vrf.network
3969 <title>MacVTap
</title>
3970 <para>This brings up a network interface
<literal>macvtap-test
</literal>
3971 and attaches it to
<literal>enp0s25
</literal>.
</para>
3972 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
3977 MACVTAP=macvtap-test
3982 <title>A Xfrm interface with physical underlying device.
</title>
3984 <programlisting># /etc/systemd/network/
27-xfrm.netdev
3989 InterfaceId=
7</programlisting>
3991 <programlisting># /etc/systemd/network/
27-eth0.network
3996 Xfrm=xfrm0
</programlisting>
3998 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
3999 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
4000 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
4006 <title>See Also
</title>
4008 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
4009 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
4010 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4011 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4012 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>