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+ -->
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>5</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>
65 <para>Note that an interface without any static IPv6 addresses configured, and neither DHCPv6
66 nor IPv6LL enabled, shall be considered to have no IPv6 support. IPv6 will be automatically
67 disabled for that interface by writing
"1" to
68 <filename>/proc/sys/net/ipv6/conf/
<replaceable>ifname
</replaceable>/disable_ipv6
</filename>.
73 <title>[Match] Section Options
</title>
75 <para>The network file contains a
<literal>[Match]
</literal>
76 section, which determines if a given network file may be applied
77 to a given device; and a
<literal>[Network]
</literal> section
78 specifying how the device should be configured. The first (in
79 lexical order) of the network files that matches a given device
80 is applied, all later files are ignored, even if they match as
83 <para>A network file is said to match a network interface if all matches specified by the
84 <literal>[Match]
</literal> section are satisfied. When a network file does not contain valid
85 settings in
<literal>[Match]
</literal> section, then the file will match all interfaces and
86 <command>systemd-networkd
</command> warns about that. Hint: to avoid the warning and to make it
87 clear that all interfaces shall be matched, add the following:
88 <programlisting>Name=*
</programlisting>
89 The following keys are accepted:
</para>
91 <variablelist class='network-directives'
>
92 <xi:include href=
"systemd.link.xml" xpointer=
"mac-address" />
93 <xi:include href=
"systemd.link.xml" xpointer=
"permanent-mac-address" />
94 <xi:include href=
"systemd.link.xml" xpointer=
"path" />
95 <xi:include href=
"systemd.link.xml" xpointer=
"driver" />
96 <xi:include href=
"systemd.link.xml" xpointer=
"type" />
97 <xi:include href=
"systemd.link.xml" xpointer=
"property" />
100 <term><varname>Name=
</varname></term>
102 <para>A whitespace-separated list of shell-style globs matching the device name, as exposed
103 by the udev property
<literal>INTERFACE
</literal>, or device's alternative names. If the
104 list is prefixed with a
"!", the test is inverted.
</para>
109 <term><varname>WLANInterfaceType=
</varname></term>
111 <para>A whitespace-separated list of wireless network type. Supported values are
112 <literal>ad-hoc
</literal>,
<literal>station
</literal>,
<literal>ap
</literal>,
113 <literal>ap-vlan
</literal>,
<literal>wds
</literal>,
<literal>monitor
</literal>,
114 <literal>mesh-point
</literal>,
<literal>p2p-client
</literal>,
<literal>p2p-go
</literal>,
115 <literal>p2p-device
</literal>,
<literal>ocb
</literal>, and
<literal>nan
</literal>. If the
116 list is prefixed with a
"!", the test is inverted.
122 <term><varname>SSID=
</varname></term>
124 <para>A whitespace-separated list of shell-style globs matching the SSID of the currently
125 connected wireless LAN. If the list is prefixed with a
"!", the test is inverted.
131 <term><varname>BSSID=
</varname></term>
133 <para>A whitespace-separated list of hardware address of the currently connected wireless
134 LAN. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example in
135 <varname>MACAddress=
</varname>. This option may appear more than one, in which case the
136 lists are merged. If the empty string is assigned to this option, the list of BSSID defined
137 prior to this is reset.
</para>
141 <xi:include href=
"systemd.link.xml" xpointer=
"host" />
142 <xi:include href=
"systemd.link.xml" xpointer=
"virtualization" />
143 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-command-line" />
144 <xi:include href=
"systemd.link.xml" xpointer=
"kernel-version" />
145 <xi:include href=
"systemd.link.xml" xpointer=
"architecture" />
151 <title>[Link] Section Options
</title>
153 <para> The
<literal>[Link]
</literal> section accepts the following keys:
</para>
155 <variablelist class='network-directives'
>
157 <term><varname>MACAddress=
</varname></term>
159 <para>The hardware address to set for the device.
</para>
163 <term><varname>MTUBytes=
</varname></term>
165 <para>The maximum transmission unit in bytes to set for the
166 device. The usual suffixes K, M, G, are supported and are
167 understood to the base of
1024.
</para>
168 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
169 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
173 <term><varname>ARP=
</varname></term>
175 <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol)
176 for this interface is enabled. When unset, the kernel's default will be used.
</para>
177 <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual
178 interfaces atop a single lower-level physical interface, which will then only serve as a
179 link/
"bridge" device aggregating traffic to the same physical link and not participate in
180 the network otherwise.
</para>
184 <term><varname>Multicast=
</varname></term>
186 <para>Takes a boolean. If set to true, the multicast flag on the device is enabled.
</para>
190 <term><varname>AllMulticast=
</varname></term>
192 <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the network.
193 This happens when multicast routing is enabled.
</para>
197 <term><varname>IPv6LinkLocalAddressGenerationMode=
</varname></term>
199 <para>Specifies how IPv6 link local address is generated. Takes one of
<literal>eui64
</literal>,
200 <literal>none
</literal>,
<literal>stable-privacy
</literal> and
<literal>random
</literal>.
201 When unset, the kernel's default will be used. Note that if
<varname>LinkLocalAdressing=
</varname>
202 not configured as
<literal>ipv6
</literal> then
<varname>IPv6LinkLocalAddressGenerationMode=
</varname>
207 <term><varname>Unmanaged=
</varname></term>
209 <para>Takes a boolean. When
<literal>yes
</literal>, no attempts are
210 made to bring up or configure matching links, equivalent to
211 when there are no matching network files. Defaults to
212 <literal>no
</literal>.
</para>
213 <para>This is useful for preventing later matching network
214 files from interfering with certain interfaces that are fully
215 controlled by other applications.
</para>
219 <term><varname>Group=
</varname></term>
221 <para>Link groups are similar to port ranges found in managed switches.
222 When network interfaces are added to a numbered group, operations on
223 all the interfaces from that group can be performed at once. An unsigned
224 integer ranges
0 to
4294967294. Default to unset.
</para>
228 <term><varname>RequiredForOnline=
</varname></term>
230 <para>Takes a boolean or a minimum operational state and an optional maximum operational state.
231 Please see
<citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
232 for possible operational states. When
<literal>yes
</literal>, the network is deemed required when
233 determining whether the system is online when running
234 <command>systemd-networkd-wait-online
</command>. When
<literal>no
</literal>, the network is ignored
235 when checking for online state. When a minimum operational state and an optional maximum operational
236 state are set,
<literal>yes
</literal> is implied, and this controls the minimum and maximum
237 operational state required for the network interface to be considered online.
238 Defaults to
<literal>yes
</literal>.
</para>
240 <para>The network will be brought up normally in all cases, but in
241 the event that there is no address being assigned by DHCP or the
242 cable is not plugged in, the link will simply remain offline and be
243 skipped automatically by
<command>systemd-networkd-wait-online
</command>
244 if
<literal>RequiredForOnline=no
</literal>.
</para>
251 <title>[Network] Section Options
</title>
253 <para>The
<literal>[Network]
</literal> section accepts the following keys:
</para>
255 <variablelist class='network-directives'
>
257 <term><varname>Description=
</varname></term>
259 <para>A description of the device. This is only used for
260 presentation purposes.
</para>
264 <term><varname>DHCP=
</varname></term>
266 <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts
267 <literal>yes
</literal>,
<literal>no
</literal>,
268 <literal>ipv4
</literal>, or
<literal>ipv6
</literal>. Defaults
269 to
<literal>no
</literal>.
</para>
271 <para>Note that DHCPv6 will by default be triggered by Router
272 Advertisement, if that is enabled, regardless of this parameter.
273 By enabling DHCPv6 support explicitly, the DHCPv6 client will
274 be started regardless of the presence of routers on the link,
275 or what flags the routers pass. See
276 <literal>IPv6AcceptRA=
</literal>.
</para>
278 <para>Furthermore, note that by default the domain name
279 specified through DHCP is not used for name resolution.
280 See option
<option>UseDomains=
</option> below.
</para>
282 <para>See the
<literal>[DHCPv4]
</literal> or
<literal>[DHCPv6]
</literal> section below for
283 further configuration options for the DHCP client support.
</para>
287 <term><varname>DHCPServer=
</varname></term>
289 <para>Takes a boolean. If set to
<literal>yes
</literal>, DHCPv4 server will be started. Defaults
290 to
<literal>no
</literal>. Further settings for the DHCP
291 server may be set in the
<literal>[DHCPServer]
</literal>
292 section described below.
</para>
296 <term><varname>LinkLocalAddressing=
</varname></term>
298 <para>Enables link-local address autoconfiguration. Accepts
<literal>yes
</literal>,
299 <literal>no
</literal>,
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
300 <literal>fallback
</literal>, or
<literal>ipv4-fallback
</literal>. If
301 <literal>fallback
</literal> or
<literal>ipv4-fallback
</literal> is specified, then an IPv4
302 link-local address is configured only when DHCPv4 fails. If
<literal>fallback
</literal>,
303 an IPv6 link-local address is always configured, and if
<literal>ipv4-fallback
</literal>,
304 the address is not configured. Note that, the fallback mechanism works only when DHCPv4
305 client is enabled, that is, it requires
<literal>DHCP=yes
</literal> or
306 <literal>DHCP=ipv4
</literal>. If
<varname>Bridge=
</varname> is set, defaults to
307 <literal>no
</literal>, and if not, defaults to
<literal>ipv6
</literal>.
312 <term><varname>IPv4LLRoute=
</varname></term>
314 <para>Takes a boolean. If set to true, sets up the route needed for
315 non-IPv4LL hosts to communicate with IPv4LL-only hosts. Defaults
321 <term><varname>DefaultRouteOnDevice=
</varname></term>
323 <para>Takes a boolean. If set to true, sets up the default route bound to the interface.
324 Defaults to false. This is useful when creating routes on point-to-point interfaces.
325 This is equivalent to e.g. the following.
326 <programlisting>ip route add default dev veth99
</programlisting></para>
330 <term><varname>IPv6Token=
</varname></term>
332 <para>Specifies an optional address generation mode and a required IPv6 address. If
333 the mode is present, the two parts must be separated with a colon
334 <literal><replaceable>mode
</replaceable>:
<replaceable>address
</replaceable></literal>. The
335 address generation mode may be either
<constant>prefixstable
</constant> or
336 <constant>static
</constant>. If not specified,
<constant>static
</constant> is assumed.
338 <para>When the mode is set to
<constant>static
</constant>, or unspecified, the lower bits of
339 the supplied address are combined with the upper bits of a prefix received in a Router Advertisement
340 message to form a complete address. Note that if multiple prefixes are received in an RA message, or in
341 multiple RA messages, addresses will be formed from each of them using the supplied address. This
342 mode implements SLAAC but uses a static interface identifier instead of an identifier generated
343 using the EUI-
64 algorithm. Because the interface identifier is static, if Duplicate Address Detection
344 detects that the computed address is a duplicate (in use by another node on the link), then this
345 mode will fail to provide an address for that prefix.
347 <para>When the mode is set to
<literal>prefixstable
</literal> the RFC
7217 algorithm for generating
348 interface identifiers will be used, but only when a prefix received in an RA message matches the supplied address.
349 See
<ulink url=
"https://tools.ietf.org/html/rfc7217">RFC
7217</ulink>. Prefix matching will be attempted
350 against each
<constant>prefixstable
</constant> IPv6Token variable provided in the configuration; if a received
351 prefix does not match any of the provided addresses, then the EUI-
64 algorithm will be used to form
352 an interface identifier for that prefix. This mode is also SLAAC, but with a potentially stable interface
353 identifier which does not directly map to the interface's hardware address.
355 Note that the
<constant>prefixstable
</constant> algorithm includes both the interface's name and
356 MAC address in the hash used to compute the interface identifier, so if either of those are changed the resulting
357 interface identifier (and address) will change, even if the prefix received in the RA message has not changed.
359 Note that if multiple
<constant>prefixstable
</constant> IPv6Token variables are supplied with addresses that
360 match a prefix received in an RA message, only the first one will be used to generate addresses.
365 <term><varname>LLMNR=
</varname></term>
367 <para>Takes a boolean or
<literal>resolve
</literal>. When true,
369 url=
"https://tools.ietf.org/html/rfc4795">Link-Local
370 Multicast Name Resolution
</ulink> on the link. When set to
371 <literal>resolve
</literal>, only resolution is enabled,
372 but not host registration and announcement. Defaults to
373 true. This setting is read by
374 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
378 <term><varname>MulticastDNS=
</varname></term>
380 <para>Takes a boolean or
<literal>resolve
</literal>. When true,
382 url=
"https://tools.ietf.org/html/rfc6762">Multicast
383 DNS
</ulink> support on the link. When set to
384 <literal>resolve
</literal>, only resolution is enabled,
385 but not host or service registration and
386 announcement. Defaults to false. This setting is read by
387 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
391 <term><varname>DNSOverTLS=
</varname></term>
393 <para>Takes a boolean or
<literal>opportunistic
</literal>.
396 url=
"https://tools.ietf.org/html/rfc7858">DNS-over-TLS
</ulink>
398 When set to
<literal>opportunistic
</literal>, compatibility with
399 non-DNS-over-TLS servers is increased, by automatically
400 turning off DNS-over-TLS servers in this case.
401 This option defines a per-interface setting for
402 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
403 global
<varname>DNSOverTLS=
</varname> option. Defaults to
404 false. This setting is read by
405 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
409 <term><varname>DNSSEC=
</varname></term>
411 <para>Takes a boolean. or
412 <literal>allow-downgrade
</literal>. When true, enables
414 url=
"https://tools.ietf.org/html/rfc4033">DNSSEC
</ulink>
415 DNS validation support on the link. When set to
416 <literal>allow-downgrade
</literal>, compatibility with
417 non-DNSSEC capable networks is increased, by automatically
418 turning off DNSSEC in this case. This option defines a
419 per-interface setting for
420 <citerefentry><refentrytitle>resolved.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
421 global
<varname>DNSSEC=
</varname> option. Defaults to
422 false. This setting is read by
423 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
427 <term><varname>DNSSECNegativeTrustAnchors=
</varname></term>
428 <listitem><para>A space-separated list of DNSSEC negative
429 trust anchor domains. If specified and DNSSEC is enabled,
430 look-ups done via the interface's DNS server will be subject
431 to the list of negative trust anchors, and not require
432 authentication for the specified domains, or anything below
433 it. Use this to disable DNSSEC authentication for specific
434 private domains, that cannot be proven valid using the
435 Internet DNS hierarchy. Defaults to the empty list. This
437 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
441 <term><varname>LLDP=
</varname></term>
443 <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol commonly
444 implemented on professional routers and bridges which announces which physical port a system is connected
445 to, as well as other related data. Accepts a boolean or the special value
446 <literal>routers-only
</literal>. When true, incoming LLDP packets are accepted and a database of all LLDP
447 neighbors maintained. If
<literal>routers-only
</literal> is set only LLDP data of various types of routers
448 is collected and LLDP data about other types of devices ignored (such as stations, telephones and
449 others). If false, LLDP reception is disabled. Defaults to
<literal>routers-only
</literal>. Use
450 <citerefentry><refentrytitle>networkctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry> to query the
451 collected neighbor data. LLDP is only available on Ethernet links. See
<varname>EmitLLDP=
</varname> below
452 for enabling LLDP packet emission from the local system.
457 <term><varname>EmitLLDP=
</varname></term>
459 <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the special values
460 <literal>nearest-bridge
</literal>,
<literal>non-tpmr-bridge
</literal> and
461 <literal>customer-bridge
</literal>. Defaults to false, which turns off LLDP packet emission. If not false,
462 a short LLDP packet with information about the local system is sent out in regular intervals on the
463 link. The LLDP packet will contain information about the local hostname, the local machine ID (as stored
464 in
<citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and the
465 local interface name, as well as the pretty hostname of the system (as set in
466 <citerefentry><refentrytitle>machine-info
</refentrytitle><manvolnum>5</manvolnum></citerefentry>). LLDP
467 emission is only available on Ethernet links. Note that this setting passes data suitable for
468 identification of host to the network and should thus not be enabled on untrusted networks, where such
469 identification data should not be made available. Use this option to permit other systems to identify on
470 which interfaces they are connected to this system. The three special values control propagation of the
471 LLDP packets. The
<literal>nearest-bridge
</literal> setting permits propagation only to the nearest
472 connected bridge,
<literal>non-tpmr-bridge
</literal> permits propagation across Two-Port MAC Relays, but
473 not any other bridges, and
<literal>customer-bridge
</literal> permits propagation until a customer bridge
474 is reached. For details about these concepts, see
<ulink
475 url=
"https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE
802.1AB-
2016</ulink>. Note that
476 configuring this setting to true is equivalent to
<literal>nearest-bridge
</literal>, the recommended and
477 most restricted level of propagation. See
<varname>LLDP=
</varname> above for an option to enable LLDP
483 <term><varname>BindCarrier=
</varname></term>
485 <para>A link name or a list of link names. When set, controls the behavior of the current
486 link. When all links in the list are in an operational down state, the current link is brought
487 down. When at least one link has carrier, the current interface is brought up.
492 <term><varname>Address=
</varname></term>
494 <para>A static IPv4 or IPv6 address and its prefix length,
495 separated by a
<literal>/
</literal> character. Specify
496 this key more than once to configure several addresses.
497 The format of the address must be as described in
498 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
499 This is a short-hand for an [Address] section only
500 containing an Address key (see below). This option may be
501 specified more than once.
504 <para>If the specified address is
<literal>0.0.0.0</literal> (for IPv4) or
<literal>::
</literal>
505 (for IPv6), a new address range of the requested size is automatically allocated from a
506 system-wide pool of unused ranges. Note that the prefix length must be equal or larger than
8 for
507 IPv4, and
64 for IPv6. The allocated range is checked against all current network interfaces and
508 all known network configuration files to avoid address range conflicts. The default system-wide
509 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.
510 This functionality is useful to manage a large number of dynamically created network interfaces
511 with the same network configuration and automatic address range assignment.
</para>
516 <term><varname>Gateway=
</varname></term>
518 <para>The gateway address, which must be in the format
520 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
521 This is a short-hand for a [Route] section only containing
522 a Gateway key. This option may be specified more than
527 <term><varname>DNS=
</varname></term>
529 <para>A DNS server address, which must be in the format
531 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
532 This option may be specified more than once. This setting is read by
533 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
537 <term><varname>Domains=
</varname></term>
539 <para>A whitespace-separated list of domains which should be resolved using the DNS servers on
540 this link. Each item in the list should be a domain name, optionally prefixed with a tilde
541 (
<literal>~
</literal>). The domains with the prefix are called
"routing-only domains". The
542 domains without the prefix are called
"search domains" and are first used as search suffixes for
543 extending single-label hostnames (hostnames containing no dots) to become fully qualified
544 domain names (FQDNs). If a single-label hostname is resolved on this interface, each of the
545 specified search domains are appended to it in turn, converting it into a fully qualified domain
546 name, until one of them may be successfully resolved.
</para>
548 <para>Both
"search" and
"routing-only" domains are used for routing of DNS queries: look-ups for hostnames
549 ending in those domains (hence also single label names, if any
"search domains" are listed), are routed to
550 the DNS servers configured for this interface. The domain routing logic is particularly useful on
551 multi-homed hosts with DNS servers serving particular private DNS zones on each interface.
</para>
553 <para>The
"routing-only" domain
<literal>~.
</literal> (the tilde indicating definition of a routing domain,
554 the dot referring to the DNS root domain which is the implied suffix of all valid DNS names) has special
555 effect. It causes all DNS traffic which does not match another configured domain routing entry to be routed
556 to DNS servers specified for this interface. This setting is useful to prefer a certain set of DNS servers
557 if a link on which they are connected is available.
</para>
559 <para>This setting is read by
560 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
561 "Search domains" correspond to the
<varname>domain
</varname> and
<varname>search
</varname> entries in
562 <citerefentry project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
563 Domain name routing has no equivalent in the traditional glibc API, which has no concept of domain
564 name servers limited to a specific link.
</para>
568 <term><varname>DNSDefaultRoute=
</varname></term>
570 <para>Takes a boolean argument. If true, this link's configured DNS servers are used for resolving domain
571 names that do not match any link's configured
<varname>Domains=
</varname> setting. If false, this link's
572 configured DNS servers are never used for such domains, and are exclusively used for resolving names that
573 match at least one of the domains configured on this link. If not specified defaults to an automatic mode:
574 queries not matching any link's configured domains will be routed to this link if it has no routing-only
575 domains configured.
</para>
579 <term><varname>NTP=
</varname></term>
581 <para>An NTP server address. This option may be specified more than once. This setting is read by
582 <citerefentry><refentrytitle>systemd-timesyncd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
586 <term><varname>IPForward=
</varname></term>
587 <listitem><para>Configures IP packet forwarding for the
588 system. If enabled, incoming packets on any network
589 interface will be forwarded to any other interfaces
590 according to the routing table. Takes a boolean,
591 or the values
<literal>ipv4
</literal> or
592 <literal>ipv6
</literal>, which only enable IP packet
593 forwarding for the specified address family. This controls
594 the
<filename>net.ipv4.ip_forward
</filename> and
595 <filename>net.ipv6.conf.all.forwarding
</filename> sysctl
596 options of the network interface (see
<ulink
597 url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink>
598 for details about sysctl options). Defaults to
599 <literal>no
</literal>.
</para>
601 <para>Note: this setting controls a global kernel option,
602 and does so one way only: if a network that has this setting
603 enabled is set up the global setting is turned on. However,
604 it is never turned off again, even after all networks with
605 this setting enabled are shut down again.
</para>
607 <para>To allow IP packet forwarding only between specific
608 network interfaces use a firewall.
</para>
612 <term><varname>IPMasquerade=
</varname></term>
613 <listitem><para>Configures IP masquerading for the network
614 interface. If enabled, packets forwarded from the network
615 interface will be appear as coming from the local host.
616 Takes a boolean argument. Implies
617 <varname>IPForward=ipv4
</varname>. Defaults to
618 <literal>no
</literal>.
</para></listitem>
621 <term><varname>IPv6PrivacyExtensions=
</varname></term>
622 <listitem><para>Configures use of stateless temporary
623 addresses that change over time (see
<ulink
624 url=
"https://tools.ietf.org/html/rfc4941">RFC
4941</ulink>,
625 Privacy Extensions for Stateless Address Autoconfiguration
626 in IPv6). Takes a boolean or the special values
627 <literal>prefer-public
</literal> and
628 <literal>kernel
</literal>. When true, enables the privacy
629 extensions and prefers temporary addresses over public
630 addresses. When
<literal>prefer-public
</literal>, enables the
631 privacy extensions, but prefers public addresses over
632 temporary addresses. When false, the privacy extensions
633 remain disabled. When
<literal>kernel
</literal>, the kernel's
634 default setting will be left in place. Defaults to
635 <literal>no
</literal>.
</para></listitem>
638 <term><varname>IPv6AcceptRA=
</varname></term>
639 <listitem><para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the
640 interface. If true, RAs are accepted; if false, RAs are ignored. When RAs are accepted, they may
641 trigger the start of the DHCPv6 client if the relevant flags are set in the RA data, or if no
642 routers are found on the link. The default is to disable RA reception for bridge devices or when IP
643 forwarding is enabled, and to enable it otherwise. Cannot be enabled on bond devices and when link
644 local addressing is disabled.
</para>
646 <para>Further settings for the IPv6 RA support may be configured in the
647 <literal>[IPv6AcceptRA]
</literal> section, see below.
</para>
649 <para>Also see
<ulink
650 url=
"https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt
</ulink> in the kernel
651 documentation regarding
<literal>accept_ra
</literal>, but note that systemd's setting of
652 <constant>1</constant> (i.e. true) corresponds to kernel's setting of
<constant>2</constant>.
</para>
654 <para>Note that kernel's implementation of the IPv6 RA protocol is always disabled,
655 regardless of this setting. If this option is enabled, a userspace implementation of the IPv6
656 RA protocol is used, and the kernel's own implementation remains disabled, since
657 <command>systemd-networkd
</command> needs to know all details supplied in the advertisements,
658 and these are not available from the kernel if the kernel's own implementation is used.
</para>
662 <term><varname>IPv6DuplicateAddressDetection=
</varname></term>
663 <listitem><para>Configures the amount of IPv6 Duplicate
664 Address Detection (DAD) probes to send. When unset, the kernel's default will be used.
668 <term><varname>IPv6HopLimit=
</varname></term>
669 <listitem><para>Configures IPv6 Hop Limit. For each router that
670 forwards the packet, the hop limit is decremented by
1. When the
671 hop limit field reaches zero, the packet is discarded.
672 When unset, the kernel's default will be used.
676 <term><varname>IPv4ProxyARP=
</varname></term>
677 <listitem><para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one host,
678 usually a router, answers ARP requests intended for another machine. By
"faking" its identity,
679 the router accepts responsibility for routing packets to the
"real" destination. (see
<ulink
680 url=
"https://tools.ietf.org/html/rfc1027">RFC
1027</ulink>.
681 When unset, the kernel's default will be used.
685 <term><varname>IPv6ProxyNDP=
</varname></term>
686 <listitem><para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery
687 Protocol) is a technique for IPv6 to allow routing of addresses to a different
688 destination when peers expect them to be present on a certain physical link.
689 In this case a router answers Neighbour Advertisement messages intended for
690 another machine by offering its own MAC address as destination.
691 Unlike proxy ARP for IPv4, it is not enabled globally, but will only send Neighbour
692 Advertisement messages for addresses in the IPv6 neighbor proxy table,
693 which can also be shown by
<command>ip -
6 neighbour show proxy
</command>.
694 systemd-networkd will control the per-interface `proxy_ndp` switch for each configured
695 interface depending on this option.
696 When unset, the kernel's default will be used.
700 <term><varname>IPv6ProxyNDPAddress=
</varname></term>
701 <listitem><para>An IPv6 address, for which Neighbour Advertisement messages will be
702 proxied. This option may be specified more than once. systemd-networkd will add the
703 <option>IPv6ProxyNDPAddress=
</option> entries to the kernel's IPv6 neighbor proxy table.
704 This option implies
<option>IPv6ProxyNDP=yes
</option> but has no effect if
705 <option>IPv6ProxyNDP
</option> has been set to false. When unset, the kernel's default will be used.
709 <term><varname>IPv6PrefixDelegation=
</varname></term>
710 <listitem><para>Whether to enable or disable Router Advertisement sending on a link.
711 Allowed values are
<literal>static
</literal> which distributes prefixes as defined in
712 the
<literal>[IPv6PrefixDelegation]
</literal> and any
<literal>[IPv6Prefix]
</literal>
713 sections,
<literal>dhcpv6
</literal> which requests prefixes using a DHCPv6 client
714 configured for another link and any values configured in the
715 <literal>[IPv6PrefixDelegation]
</literal> section while ignoring all static prefix
716 configuration sections,
<literal>yes
</literal> which uses both static configuration
717 and DHCPv6, and
<literal>false
</literal> which turns off IPv6 prefix delegation
718 altogether. Defaults to
<literal>false
</literal>. See the
719 <literal>[IPv6PrefixDelegation]
</literal> and the
<literal>[IPv6Prefix]
</literal>
720 sections for more configuration options.
724 <term><varname>IPv6MTUBytes=
</varname></term>
725 <listitem><para>Configures IPv6 maximum transmission unit (MTU).
726 An integer greater than or equal to
1280 bytes. When unset, the kernel's default will be used.
730 <term><varname>Bridge=
</varname></term>
732 <para>The name of the bridge to add the link to. See
733 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
738 <term><varname>Bond=
</varname></term>
740 <para>The name of the bond to add the link to. See
741 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
746 <term><varname>VRF=
</varname></term>
748 <para>The name of the VRF to add the link to. See
749 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
754 <term><varname>VLAN=
</varname></term>
756 <para>The name of a VLAN to create on the link. See
757 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
758 This option may be specified more than once.
</para>
762 <term><varname>IPVLAN=
</varname></term>
764 <para>The name of a IPVLAN to create on the link. See
765 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
766 This option may be specified more than once.
</para>
770 <term><varname>MACVLAN=
</varname></term>
772 <para>The name of a MACVLAN to create on the link. See
773 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
774 This option may be specified more than once.
</para>
778 <term><varname>VXLAN=
</varname></term>
780 <para>The name of a VXLAN to create on the link. See
781 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
782 This option may be specified more than once.
</para>
786 <term><varname>Tunnel=
</varname></term>
788 <para>The name of a Tunnel to create on the link. See
789 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
790 This option may be specified more than once.
</para>
794 <term><varname>MACsec=
</varname></term>
796 <para>The name of a MACsec device to create on the link. See
797 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
798 This option may be specified more than once.
</para>
802 <term><varname>ActiveSlave=
</varname></term>
804 <para>Takes a boolean. Specifies the new active slave. The
<literal>ActiveSlave=
</literal>
805 option is only valid for following modes:
806 <literal>active-backup
</literal>,
807 <literal>balance-alb
</literal> and
808 <literal>balance-tlb
</literal>. Defaults to false.
813 <term><varname>PrimarySlave=
</varname></term>
815 <para>Takes a boolean. Specifies which slave is the primary device. The specified
816 device will always be the active slave while it is available. Only when the
817 primary is off-line will alternate devices be used. This is useful when
818 one slave is preferred over another, e.g. when one slave has higher throughput
819 than another. The
<literal>PrimarySlave=
</literal> option is only valid for
821 <literal>active-backup
</literal>,
822 <literal>balance-alb
</literal> and
823 <literal>balance-tlb
</literal>. Defaults to false.
828 <term><varname>ConfigureWithoutCarrier=
</varname></term>
830 <para>Takes a boolean. Allows networkd to configure a specific link even if it has no carrier.
831 Defaults to false. If
<option>IgnoreCarrierLoss=
</option> is not explicitly set, it will
832 default to this value.
837 <term><varname>IgnoreCarrierLoss=
</varname></term>
839 <para>Takes a boolean. Allows networkd to retain both the static and dynamic configuration
840 of the interface even if its carrier is lost. When unset, the value specified with
841 <option>ConfigureWithoutCarrier=
</option> is used.
846 <term><varname>Xfrm=
</varname></term>
848 <para>The name of the xfrm to create on the link. See
849 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
850 This option may be specified more than once.
</para>
854 <term><varname>KeepConfiguration=
</varname></term>
856 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
857 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
858 will not drop static addresses and routes on starting up process. When set to
859 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
860 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
861 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
862 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
863 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
864 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
865 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
<literal>no
</literal>.
875 <title>[Address] Section Options
</title>
877 <para>An
<literal>[Address]
</literal> section accepts the
878 following keys. Specify several
<literal>[Address]
</literal>
879 sections to configure several addresses.
</para>
881 <variablelist class='network-directives'
>
883 <term><varname>Address=
</varname></term>
885 <para>As in the
<literal>[Network]
</literal> section. This key is mandatory. Each
886 <literal>[Address]
</literal> section can contain one
<varname>Address=
</varname> setting.
</para>
890 <term><varname>Peer=
</varname></term>
892 <para>The peer address in a point-to-point connection.
893 Accepts the same format as the
<varname>Address=
</varname>
898 <term><varname>Broadcast=
</varname></term>
900 <para>The broadcast address, which must be in the format
902 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
903 This key only applies to IPv4 addresses. If it is not
904 given, it is derived from the
<varname>Address=
</varname>
909 <term><varname>Label=
</varname></term>
911 <para>An address label.
</para>
915 <term><varname>PreferredLifetime=
</varname></term>
917 <para>Allows the default
"preferred lifetime" of the address to be overridden.
918 Only three settings are accepted:
<literal>forever
</literal> or
<literal>infinity
</literal>
919 which is the default and means that the address never expires, and
<literal>0</literal> which means
920 that the address is considered immediately
"expired" and will not be used,
921 unless explicitly requested. A setting of PreferredLifetime=
0 is useful for
922 addresses which are added to be used only by a specific application,
923 which is then configured to use them explicitly.
</para>
927 <term><varname>Scope=
</varname></term>
929 <para>The scope of the address, which can be
<literal>global
</literal>,
930 <literal>link
</literal> or
<literal>host
</literal> or an unsigned integer ranges
0 to
255.
931 Defaults to
<literal>global
</literal>.
</para>
935 <term><varname>HomeAddress=
</varname></term>
937 <para>Takes a boolean. Designates this address the
"home address" as defined in
938 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>.
939 Supported only on IPv6. Defaults to false.
</para>
943 <term><varname>DuplicateAddressDetection=
</varname></term>
945 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
946 <literal>both
</literal>,
<literal>none
</literal>. When
<literal>ipv4
</literal>,
947 performs IPv4 Duplicate Address Detection. See
948 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5224</ulink>.
949 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
950 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>.
951 Defaults to
<literal>ipv6
</literal>.
</para>
955 <term><varname>ManageTemporaryAddress=
</varname></term>
957 <para>Takes a boolean. If true the kernel manage temporary addresses created
958 from this one as template on behalf of Privacy Extensions
959 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become
960 active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
961 The given address needs to have a prefix length of
64. This flag allows using privacy
962 extensions in a manually configured network, just like if stateless auto-configuration
963 was active. Defaults to false.
</para>
967 <term><varname>AddPrefixRoute=
</varname></term>
969 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
970 Defaults to true.
</para>
974 <term><varname>AutoJoin=
</varname></term>
976 <para>Takes a boolean. Joining multicast group on ethernet level via
977 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
978 IGMP snooping since the switch would not replicate multicast packets on ports that did not
979 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
980 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
981 that enables then to do the required join. By extending ip address command with option
982 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
983 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
984 Defaults to
<literal>no
</literal>.
</para>
991 <title>[Neighbor] Section Options
</title>
992 <para>A
<literal>[Neighbor]
</literal> section accepts the
993 following keys. The neighbor section adds a permanent, static
994 entry to the neighbor table (IPv6) or ARP table (IPv4) for
995 the given hardware address on the links matched for the network.
996 Specify several
<literal>[Neighbor]
</literal> sections to configure
997 several static neighbors.
</para>
999 <variablelist class='network-directives'
>
1001 <term><varname>Address=
</varname></term>
1003 <para>The IP address of the neighbor.
</para>
1007 <term><varname>LinkLayerAddress=
</varname></term>
1009 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1016 <title>[IPv6AddressLabel] Section Options
</title>
1018 <para>An
<literal>[IPv6AddressLabel]
</literal> section accepts the
1019 following keys. Specify several
<literal>[IPv6AddressLabel]
</literal>
1020 sections to configure several address labels. IPv6 address labels are
1021 used for address selection. See
<ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>.
1022 Precedence is managed by userspace, and only the label itself is stored in the kernel
</para>
1024 <variablelist class='network-directives'
>
1026 <term><varname>Label=
</varname></term>
1028 <para> The label for the prefix (an unsigned integer) ranges
0 to
4294967294.
1029 0xffffffff is reserved. This key is mandatory.
</para>
1033 <term><varname>Prefix=
</varname></term>
1035 <para>IPv6 prefix is an address with a prefix length, separated by a slash
<literal>/
</literal> character.
1036 This key is mandatory.
</para>
1043 <title>[RoutingPolicyRule] Section Options
</title>
1045 <para>An
<literal>[RoutingPolicyRule]
</literal> section accepts the
1046 following keys. Specify several
<literal>[RoutingPolicyRule]
</literal>
1047 sections to configure several rules.
</para>
1049 <variablelist class='network-directives'
>
1051 <term><varname>TypeOfService=
</varname></term>
1053 <para>Specifies the type of service to match a number between
0 to
255.
</para>
1057 <term><varname>From=
</varname></term>
1059 <para>Specifies the source address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1063 <term><varname>To=
</varname></term>
1065 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1069 <term><varname>FirewallMark=
</varname></term>
1071 <para>Specifies the iptables firewall mark value to match (a number between
1 and
4294967295).
</para>
1075 <term><varname>Table=
</varname></term>
1077 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes
1078 one of
<literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>,
1079 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1083 <term><varname>Priority=
</varname></term>
1085 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an unsigned
1086 integer. Higher number means lower priority, and rules get processed in order of increasing number.
</para>
1090 <term><varname>IncomingInterface=
</varname></term>
1092 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches packets originating from this host.
</para>
1096 <term><varname>OutgoingInterface=
</varname></term>
1098 <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>
1102 <term><varname>SourcePort=
</varname></term>
1104 <para>Specifies the source IP port or IP port range match in forwarding information base (FIB) rules.
1105 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1109 <term><varname>DestinationPort=
</varname></term>
1111 <para>Specifies the destination IP port or IP port range match in forwarding information base (FIB) rules.
1112 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1116 <term><varname>IPProtocol=
</varname></term>
1118 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP protocol name such as
<literal>tcp
</literal>,
1119 <literal>udp
</literal> or
<literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
<literal>tcp
</literal> or
1120 <literal>17</literal> for
<literal>udp
</literal>.
1121 Defaults to unset.
</para>
1125 <term><varname>InvertRule=
</varname></term>
1127 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1131 <term><varname>Family=
</varname></term>
1133 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1134 <literal>both
</literal>. By default, the address family is determined by the address
1135 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1136 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1137 <literal>ipv4
</literal>.
</para>
1141 <term><varname>User=
</varname></term>
1143 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1148 <term><varname>SuppressPrefixLength=
</varname></term>
1150 <para>Takes a number
<replaceable>N
</replaceable> in the range
0-
128 and rejects routing
1151 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1159 <title>[NextHop] Section Options
</title>
1160 <para>The
<literal>[NextHop]
</literal> section accepts the
1161 following keys. Specify several
<literal>[NextHop]
</literal>
1162 sections to configure several nexthop. Nexthop is used to manipulate entries in the kernel's nexthop
1165 <variablelist class='network-directives'
>
1167 <term><varname>Gateway=
</varname></term>
1169 <para>As in the
<literal>[Network]
</literal> section. This is mandatory.
</para>
1173 <term><varname>Id=
</varname></term>
1175 <para>The id of the nexthop (an unsigned integer). If unspecified or '
0' then automatically chosen by kernel.
</para>
1182 <title>[Route] Section Options
</title>
1183 <para>The
<literal>[Route]
</literal> section accepts the
1184 following keys. Specify several
<literal>[Route]
</literal>
1185 sections to configure several routes.
</para>
1187 <variablelist class='network-directives'
>
1189 <term><varname>Gateway=
</varname></term>
1191 <para>Takes the gateway address or special value
<literal>_dhcp
</literal>. If
1192 <literal>_dhcp
</literal>, then the gateway address provided by DHCP (or in the IPv6 case,
1193 provided by IPv6 RA) is used.
</para>
1197 <term><varname>GatewayOnLink=
</varname></term>
1199 <para>Takes a boolean. If set to true, the kernel does not have
1200 to check if the gateway is reachable directly by the current machine (i.e., the kernel does
1201 not need to check if the gateway is attached to the local network), so that we can insert the
1202 route in the kernel table without it being complained about. Defaults to
<literal>no
</literal>.
1207 <term><varname>Destination=
</varname></term>
1209 <para>The destination prefix of the route. Possibly
1210 followed by a slash and the prefix length. If omitted, a
1211 full-length host route is assumed.
</para>
1215 <term><varname>Source=
</varname></term>
1217 <para>The source prefix of the route. Possibly followed by
1218 a slash and the prefix length. If omitted, a full-length
1219 host route is assumed.
</para>
1223 <term><varname>Metric=
</varname></term>
1225 <para>The metric of the route (an unsigned integer).
</para>
1229 <term><varname>IPv6Preference=
</varname></term>
1231 <para>Specifies the route preference as defined in
<ulink
1232 url=
"https://tools.ietf.org/html/rfc4191">RFC4191
</ulink> for Router Discovery messages.
1233 Which can be one of
<literal>low
</literal> the route has a lowest priority,
1234 <literal>medium
</literal> the route has a default priority or
1235 <literal>high
</literal> the route has a highest priority.
</para>
1239 <term><varname>Scope=
</varname></term>
1241 <para>The scope of the route, which can be
<literal>global
</literal>,
<literal>site
</literal>,
1242 <literal>link
</literal>,
<literal>host
</literal>, or
<literal>nowhere
</literal>. For IPv4 route,
1243 defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
<literal>local
</literal>
1244 or
<literal>nat
</literal>, and
<literal>link
</literal> if
<varname>Type=
</varname> is
1245 <literal>broadcast
</literal>,
<literal>multicast
</literal>, or
<literal>anycast
</literal>.
1246 In other cases, defaults to
<literal>global
</literal>.
</para>
1250 <term><varname>PreferredSource=
</varname></term>
1252 <para>The preferred source address of the route. The address
1253 must be in the format described in
1254 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
1258 <term><varname>Table=
</varname></term>
1260 <para>The table identifier for the route. Takes
<literal>default
</literal>,
1261 <literal>main
</literal>,
<literal>local
</literal> or a number between
1 and
4294967295.
1262 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1263 If unset and
<varname>Type=
</varname> is
<literal>local
</literal>,
<literal>broadcast
</literal>,
1264 <literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1265 In other cases, defaults to
<literal>main
</literal>.
1270 <term><varname>Protocol=
</varname></term>
1272 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special values
1273 <literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1274 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1279 <term><varname>Type=
</varname></term>
1281 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1282 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1283 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1284 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1285 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e. a
1286 route indicating the path to take to a destination network address. If
<literal>blackhole
</literal>, packets
1287 to the defined route are discarded silently. If
<literal>unreachable
</literal>, packets to the defined route
1288 are discarded and the ICMP message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets
1289 to the defined route are discarded and the ICMP message
"Communication Administratively Prohibited" is
1290 generated. If
<literal>throw
</literal>, route lookup in the current routing table will fail and the route
1291 selection process will return to Routing Policy Database (RPDB). Defaults to
<literal>unicast
</literal>.
1296 <term><varname>InitialCongestionWindow=
</varname></term>
1298 <para>The TCP initial congestion window is used during the start of a TCP connection. During the start of a TCP
1299 session, when a client requests a resource, the server's initial congestion window determines how many data bytes
1300 will be sent during the initial burst of data. Takes a size in bytes between
1 and
4294967295 (
2^
32 -
1). The usual
1301 suffixes K, M, G are supported and are understood to the base of
1024. When unset, the kernel's default will be used.
1306 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1308 <para>The TCP initial advertised receive window is the amount of receive data (in bytes) that can initially be buffered at one time
1309 on a connection. The sending host can send only that amount of data before waiting for an acknowledgment and window update
1310 from the receiving host. Takes a size in bytes between
1 and
4294967295 (
2^
32 -
1). The usual suffixes K, M, G are supported
1311 and are understood to the base of
1024. When unset, the kernel's default will be used.
1316 <term><varname>QuickAck=
</varname></term>
1318 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the kernel's default will be used.
1323 <term><varname>FastOpenNoCookie=
</varname></term>
1325 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1326 When unset, the kernel's default will be used.
1331 <term><varname>TTLPropagate=
</varname></term>
1333 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1334 When unset, the kernel's default will be used.
1339 <term><varname>MTUBytes=
</varname></term>
1341 <para>The maximum transmission unit in bytes to set for the
1342 route. The usual suffixes K, M, G, are supported and are
1343 understood to the base of
1024.
</para>
1344 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
1345 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
1349 <term><varname>IPServiceType=
</varname></term>
1351 <para>Takes string;
<literal>CS6
</literal> or
<literal>CS4
</literal>. Used to set IP
1352 service type to CS6 (network control) or CS4 (Realtime). Defaults to CS6.
</para>
1356 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1358 <para>Configures multipath route. Multipath routing is the technique of using multiple
1359 alternative paths through a network. Takes gateway address. Optionally, takes a network
1360 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for
1361 this multipath route separated with whitespace. This setting can be specified multiple
1362 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
1369 <title>[DHCPv4] Section Options
</title>
1370 <para>The
<literal>[DHCPv4]
</literal> section configures the
1371 DHCPv4 client, if it is enabled with the
1372 <varname>DHCP=
</varname> setting described above:
</para>
1374 <variablelist class='network-directives'
>
1376 <term><varname>UseDNS=
</varname></term>
1378 <para>When true (the default), the DNS servers received
1379 from the DHCP server will be used and take precedence over
1380 any statically configured ones.
</para>
1382 <para>This corresponds to the
<option>nameserver
</option>
1383 option in
<citerefentry
1384 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1388 <term><varname>RoutesToDNS=
</varname></term>
1390 <para>When true, the routes to the DNS servers received from the DHCP server will be
1391 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored.
1392 Defaults to false.
</para>
1396 <term><varname>UseNTP=
</varname></term>
1398 <para>When true (the default), the NTP servers received
1399 from the DHCP server will be used by systemd-timesyncd
1400 and take precedence over any statically configured ones.
</para>
1404 <term><varname>UseSIP=
</varname></term>
1406 <para>When true (the default), the SIP servers received
1407 from the DHCP server will be saved at the state files and can be
1408 read via
<function>sd_network_link_get_sip_servers()
</function> function.
</para>
1413 <term><varname>UseMTU=
</varname></term>
1415 <para>When true, the interface maximum transmission unit
1416 from the DHCP server will be used on the current link.
1417 If
<varname>MTUBytes=
</varname> is set, then this setting is ignored.
1418 Defaults to false.
</para>
1422 <term><varname>Anonymize=
</varname></term>
1424 <para>Takes a boolean. When true, the options sent to the DHCP server will
1425 follow the
<ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink>
1426 (Anonymity Profiles for DHCP Clients) to minimize disclosure of identifying information.
1427 Defaults to false.
</para>
1429 <para>This option should only be set to true when
1430 <varname>MACAddressPolicy=
</varname> is set to
<literal>random
</literal>
1432 project='man-pages'
><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
</para>
1434 <para>Note that this configuration will overwrite others.
1435 In concrete, the following variables will be ignored:
1436 <varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1437 <varname>UseRoutes=
</varname>,
<varname>UseMTU=
</varname>,
1438 <varname>VendorClassIdentifier=
</varname>,
<varname>UseTimezone=
</varname>.
</para>
1440 <para>With this option enabled DHCP requests will mimic those generated by Microsoft Windows, in
1441 order to reduce the ability to fingerprint and recognize installations. This means DHCP request
1442 sizes will grow and lease data will be more comprehensive than normally, though most of the
1443 requested data is not actually used.
</para>
1447 <term><varname>SendHostname=
</varname></term>
1449 <para>When true (the default), the machine's hostname will be sent to the DHCP server.
1450 Note that the machine's hostname must consist only of
7-bit ASCII lower-case characters and
1451 no spaces or dots, and be formatted as a valid DNS domain name. Otherwise, the hostname is not
1452 sent even if this is set to true.
</para>
1457 <term><varname>MUDURL=
</varname></term>
1459 <para>When configured, the Manufacturer Usage Descriptions (MUD) URL will be sent to the
1460 DHCPv4 server. Takes an URL of length up to
255 characters. A superficial verification that
1461 the string is a valid URL will be performed. DHCPv4 clients are intended to have at most one
1462 MUD URL associated with them. See
1463 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
</para>
1468 <term><varname>UseHostname=
</varname></term>
1470 <para>When true (the default), the hostname received from
1471 the DHCP server will be set as the transient hostname of the system.
1476 <term><varname>Hostname=
</varname></term>
1478 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's hostname.
1479 Note that the specified hostname must consist only of
7-bit ASCII lower-case characters and
1480 no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1484 <term><varname>UseDomains=
</varname></term>
1486 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
1487 received from the DHCP server will be used as DNS search domain over this link, similar to the effect of
1488 the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name received from
1489 the DHCP server will be used for routing DNS queries only, but not for searching, similar to the effect of
1490 the
<option>Domains=
</option> setting when the argument is prefixed with
<literal>~
</literal>. Defaults to
1493 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
1494 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
1495 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
1496 single-label names.
</para>
1498 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
1499 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1503 <term><varname>UseRoutes=
</varname></term>
1505 <para>When true (the default), the static routes will be requested from the DHCP server and added to the
1506 routing table with a metric of
1024, and a scope of
"global",
"link" or
"host", depending on the route's
1507 destination and gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the
1508 link's own address, the scope will be set to
"host". Otherwise if the gateway is null (a direct route), a
1509 "link" scope will be used. For anything else, scope defaults to
"global".
</para>
1513 <term><varname>UseGateway=
</varname></term>
1515 <para>When true, the gateway will be requested from the DHCP server and added to the routing table with a
1516 metric of
1024, and a scope of
"link". When unset, the value specified with
<option>UseRoutes=
</option>
1521 <term><varname>UseTimezone=
</varname></term>
1523 <listitem><para>When true, the timezone received from the
1524 DHCP server will be set as timezone of the local
1525 system. Defaults to
<literal>no
</literal>.
</para></listitem>
1529 <term><varname>ClientIdentifier=
</varname></term>
1531 <para>The DHCPv4 client identifier to use. Takes one of
<literal>mac
</literal>,
<literal>duid
</literal> or
<literal>duid-only
</literal>.
1532 If set to
<literal>mac
</literal>, the MAC address of the link is used.
1533 If set to
<literal>duid
</literal>, an RFC4361-compliant Client ID, which is the combination of IAID and DUID (see below), is used.
1534 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.
1535 Defaults to
<literal>duid
</literal>.
</para>
1540 <term><varname>VendorClassIdentifier=
</varname></term>
1542 <para>The vendor class identifier used to identify vendor
1543 type and configuration.
</para>
1548 <term><varname>UserClass=
</varname></term>
1550 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or applications
1551 it represents. The information contained in this option is a string that represents the user class of which
1552 the client is a member. Each class sets an identifying string of information to be used by the DHCP
1553 service to classify clients. Takes a whitespace-separated list of strings.
</para>
1558 <term><varname>MaxAttempts=
</varname></term>
1560 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
1561 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>.
1562 Note that the time between retries is increased exponentially, so the network will not be
1563 overloaded even if this number is high.
</para>
1568 <term><varname>DUIDType=
</varname></term>
1570 <para>Override the global
<varname>DUIDType
</varname> setting for this network. See
1571 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1572 for a description of possible values.
</para>
1577 <term><varname>DUIDRawData=
</varname></term>
1579 <para>Override the global
<varname>DUIDRawData
</varname> setting for this network. See
1580 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1581 for a description of possible values.
</para>
1586 <term><varname>IAID=
</varname></term>
1588 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned integer.
</para>
1593 <term><varname>RequestBroadcast=
</varname></term>
1595 <para>Request the server to use broadcast messages before
1596 the IP address has been configured. This is necessary for
1597 devices that cannot receive RAW packets, or that cannot
1598 receive packets at all before an IP address has been
1599 configured. On the other hand, this must not be enabled on
1600 networks where broadcasts are filtered out.
</para>
1605 <term><varname>RouteMetric=
</varname></term>
1607 <para>Set the routing metric for routes specified by the
1613 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1615 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to unset).
1616 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1618 <para>When used in combination with
<varname>VRF=
</varname> the
1619 VRF's routing table is used unless this parameter is specified.
1625 <term><varname>RouteMTUBytes=
</varname></term>
1627 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further details.
</para>
1632 <term><varname>ListenPort=
</varname></term>
1634 <para>Allow setting custom port for the DHCP client to listen on.
</para>
1639 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
1641 <para>Allows to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease lifetime.
1642 Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal> means that the address
1643 never expires. Defaults to unset.
</para>
1648 <term><varname>SendRelease=
</varname></term>
1650 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops.
1651 Defaults to true.
</para>
1656 <term><varname>SendDecline=
</varname></term>
1658 <para>A boolean. When
<literal>true
</literal>, DHCPv4 clients receives IP address from DHCP server.
1659 After new IP is received, DHCPv4 performs IPv4 Duplicate Address Detection. If duplicate use of IP is detected
1660 the DHCPv4 client rejects the IP by sending a DHCPDECLINE packet DHCP clients try to obtain an IP address again.
1661 See
<ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5224</ulink>.
1662 Defaults to
<literal>unset
</literal>.
</para>
1667 <term><varname>BlackList=
</varname></term>
1669 <para>A whitespace-separated list of IPv4 addresses. DHCP offers from servers in the list are rejected.
</para>
1674 <term><varname>RequestOptions=
</varname></term>
1676 <para>When configured, allows to set arbitrary request options in the DHCPv4 request options list and will be
1677 sent to the DHCPV4 server. A whitespace-separated list of integers in the range
1.
.254. Defaults to unset.
</para>
1682 <term><varname>SendOption=
</varname></term>
1684 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data type
1685 and data separated with a colon
1686 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1687 The option number must be an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
1688 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
1689 <literal>string
</literal>. Special characters in the data string may be escaped using
1690 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1691 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1692 then all options specified earlier are cleared. Defaults to unset.
</para>
1697 <term><varname>SendVendorOption=
</varname></term>
1699 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data type
1700 and data separated with a colon
1701 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1702 The option number must be an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
1703 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
1704 <literal>string
</literal>. Special characters in the data string may be escaped using
1705 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1706 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1707 then all options specified earlier are cleared. Defaults to unset.
</para>
1714 <title>[DHCPv6] Section Options
</title>
1715 <para>The
<literal>[DHCPv6]
</literal> section configures the DHCPv6 client, if it is enabled with the
1716 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
</para>
1718 <variablelist class='network-directives'
>
1720 <term><varname>UseDNS=
</varname></term>
1721 <term><varname>UseNTP=
</varname></term>
1723 <para>As in the
<literal>[DHCPv4]
</literal> section.
</para>
1728 <term><varname>RapidCommit=
</varname></term>
1730 <para>Takes a boolean. The DHCPv6 client can obtain configuration parameters from a DHCPv6 server through
1731 a rapid two-message exchange (solicit and reply). When the rapid commit option is enabled by both
1732 the DHCPv6 client and the DHCPv6 server, the two-message exchange is used, rather than the default
1733 four-method exchange (solicit, advertise, request, and reply). The two-message exchange provides
1734 faster client configuration and is beneficial in environments in which networks are under a heavy load.
1735 See
<ulink url=
"https://tools.ietf.org/html/rfc3315#section-17.2.1">RFC
3315</ulink> for details.
1736 Defaults to true.
</para>
1741 <term><varname>MUDURL=
</varname></term>
1743 <para>When configured, the Manufacturer Usage Descriptions (MUD) URL will be sent to the DHCPV6 server.
1744 Takes an URL of length up to
255 characters. A superficial verification that the string is a valid URL
1745 will be performed. DHCPv6 clients are intended to have at most one MUD URL associated with them. See
1746 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
</para>
1751 <term><varname>RequestOptions=
</varname></term>
1753 <para>When configured, allows to set arbitrary request options in the DHCPv6 request options list and will
1754 sent to the DHCPV6 server. A whitespace-separated list of integers in the range
1.
.254. Defaults to unset.
</para>
1759 <term><varname>ForceDHCPv6PDOtherInformation=
</varname></term>
1761 <para>Takes a boolean that enforces DHCPv6 stateful mode when the 'Other information' bit is set in
1762 Router Advertisement messages. By default setting only the 'O' bit in Router Advertisements
1763 makes DHCPv6 request network information in a stateless manner using a two-message Information
1764 Request and Information Reply message exchange.
1765 <ulink url=
"https://tools.ietf.org/html/rfc7084">RFC
7084</ulink>, requirement WPD-
4, updates
1766 this behavior for a Customer Edge router so that stateful DHCPv6 Prefix Delegation is also
1767 requested when only the 'O' bit is set in Router Advertisements. This option enables such a CE
1768 behavior as it is impossible to automatically distinguish the intention of the 'O' bit otherwise.
1769 By default this option is set to 'false', enable it if no prefixes are delegated when the device
1770 should be acting as a CE router.
</para>
1775 <term><varname>PrefixDelegationHint=
</varname></term>
1777 <para>Takes an IPv6 address with prefix length as
<varname>Address=
</varname> in
1778 the
"[Network]" section. Specifies the DHCPv6 client for the requesting router to include
1779 a prefix-hint in the DHCPv6 solicitation. Prefix ranges
1.
.128. Defaults to unset.
</para>
1784 <term><varname>WithoutRA=
</varname></term>
1786 <para>When true, DHCPv6 client starts without router advertisements's managed or other address configuration flag.
1787 Defaults to false.
</para>
1792 <term><varname>SendOption=
</varname></term>
1794 <para>As in the
<literal>[DHCPv4]
</literal> section, however because DHCPv6 uses
16-bit fields to store
1795 option numbers, the option number is an integer in the range
1.
.65536.
</para>
1800 <term><varname>UserClass=
</varname></term>
1802 <para>A DHCPv6 client can use User Class option to identify the type or category of user or applications
1803 it represents. The information contained in this option is a string that represents the user class of which
1804 the client is a member. Each class sets an identifying string of information to be used by the DHCP
1805 service to classify clients. Special characters in the data string may be escaped using
1806 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1807 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1808 then all options specified earlier are cleared. Takes a whitespace-separated list of strings. Note that
1809 currently NUL bytes are not allowed.
</para>
1814 <term><varname>VendorClass=
</varname></term>
1816 <para>A DHCPv6 client can use VendorClass option to identify the vendor that
1817 manufactured the hardware on which the client is running. The information
1818 contained in the data area of this option is contained in one or more opaque
1819 fields that identify details of the hardware configuration. Takes a
1820 whitespace-separated list of strings.
</para>
1827 <title>[IPv6AcceptRA] Section Options
</title>
1828 <para>The
<literal>[IPv6AcceptRA]
</literal> section configures the IPv6 Router Advertisement
1829 (RA) client, if it is enabled with the
<varname>IPv6AcceptRA=
</varname> setting described
1832 <variablelist class='network-directives'
>
1834 <term><varname>UseDNS=
</varname></term>
1836 <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take
1837 precedence over any statically configured ones.
</para>
1839 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
1840 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1845 <term><varname>UseDomains=
</varname></term>
1847 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
1848 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
1849 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
1850 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
1851 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
1852 <literal>~
</literal>. Defaults to false.
</para>
1854 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
1855 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
1856 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
1857 single-label names.
</para>
1859 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
1860 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1865 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1867 <para>The table identifier for the routes received in the Router Advertisement
1868 (a number between
1 and
4294967295, or
0 to unset).
1869 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1875 <term><varname>UseAutonomousPrefix=
</varname></term>
1877 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
1878 precedence over any statically configured ones.
</para>
1883 <term><varname>UseOnLinkPrefix=
</varname></term>
1885 <para>When true (the default), the onlink prefix received in the Router Advertisement will be used and take
1886 precedence over any statically configured ones.
</para>
1891 <term><varname>BlackList=
</varname></term>
1893 <para>A whitespace-separated list of IPv6 prefixes. IPv6 prefixes supplied via router advertisements in the list are ignored.
</para>
1898 <term><varname>DHCPv6Client=
</varname></term>
1900 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true (the default), the DHCPv6 client will be started when the
1901 RA has the managed or other information flag. If set to
<literal>always
</literal>, the DHCPv6 client will be started even if there is no
1902 managed or other information flag in the RA.
</para>
1909 <title>[DHCPServer] Section Options
</title>
1910 <para>The
<literal>[DHCPServer]
</literal> section contains
1911 settings for the DHCP server, if enabled via the
1912 <varname>DHCPServer=
</varname> option described above:
</para>
1914 <variablelist class='network-directives'
>
1917 <term><varname>PoolOffset=
</varname></term>
1918 <term><varname>PoolSize=
</varname></term>
1920 <listitem><para>Configures the pool of addresses to hand out. The pool
1921 is a contiguous sequence of IP addresses in the subnet configured for
1922 the server address, which does not include the subnet nor the broadcast
1923 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
1924 from the start of subnet, or zero to use the default value.
1925 <varname>PoolSize=
</varname> takes the number of IP addresses in the
1926 pool or zero to use the default value. By default, the pool starts at
1927 the first address after the subnet address and takes up the rest of
1928 the subnet, excluding the broadcast address. If the pool includes
1929 the server address (the default), this is reserved and not handed
1930 out to clients.
</para></listitem>
1934 <term><varname>DefaultLeaseTimeSec=
</varname></term>
1935 <term><varname>MaxLeaseTimeSec=
</varname></term>
1937 <listitem><para>Control the default and maximum DHCP lease
1938 time to pass to clients. These settings take time values in seconds or
1939 another common time unit, depending on the suffix. The default
1940 lease time is used for clients that did not ask for a specific
1941 lease time. If a client asks for a lease time longer than the
1942 maximum lease time, it is automatically shortened to the
1943 specified time. The default lease time defaults to
1h, the
1944 maximum lease time to
12h. Shorter lease times are beneficial
1945 if the configuration data in DHCP leases changes frequently
1946 and clients shall learn the new settings with shorter
1947 latencies. Longer lease times reduce the generated DHCP
1948 network traffic.
</para></listitem>
1952 <term><varname>EmitDNS=
</varname></term>
1953 <term><varname>DNS=
</varname></term>
1955 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
1956 to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>.
1957 The DNS servers to pass to clients may be configured with the
1958 <varname>DNS=
</varname> option, which takes a list of IPv4
1959 addresses. If the
<varname>EmitDNS=
</varname> option is
1960 enabled but no servers configured, the servers are
1961 automatically propagated from an
"uplink" interface that has
1962 appropriate servers set. The
"uplink" interface is determined
1963 by the default route of the system with the highest
1964 priority. Note that this information is acquired at the time
1965 the lease is handed out, and does not take uplink interfaces
1966 into account that acquire DNS or NTP server information at a
1967 later point. DNS server propagation does not take
1968 <filename>/etc/resolv.conf
</filename> into account. Also, note
1969 that the leases are not refreshed if the uplink network
1970 configuration changes. To ensure clients regularly acquire the
1971 most current uplink DNS server information, it is thus
1972 advisable to shorten the DHCP lease time via
1973 <varname>MaxLeaseTimeSec=
</varname> described
1974 above.
</para></listitem>
1978 <term><varname>EmitNTP=
</varname></term>
1979 <term><varname>NTP=
</varname></term>
1981 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
1982 <varname>DNS=
</varname> settings described above, these
1983 settings configure whether and what NTP server information
1984 shall be emitted as part of the DHCP lease. The same syntax,
1985 propagation semantics and defaults apply as for
1986 <varname>EmitDNS=
</varname> and
1987 <varname>DNS=
</varname>.
</para></listitem>
1991 <term><varname>EmitSIP=
</varname></term>
1992 <term><varname>SIP=
</varname></term>
1994 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
1995 <varname>DNS=
</varname> settings described above, these
1996 settings configure whether and what SIP server information
1997 shall be emitted as part of the DHCP lease. The same syntax,
1998 propagation semantics and defaults apply as for
1999 <varname>EmitDNS=
</varname> and
2000 <varname>DNS=
</varname>.
</para></listitem>
2004 <term><varname>POP3Servers=
</varname></term>
2006 <listitem><para>Similar to the
<varname>DNS=
</varname> setting described above, this setting
2007 configures whether and what POP3 server information shall be emitted as part of the DHCP lease. The
2008 same syntax, propagation semantics and defaults apply as for
2009 <varname>DNS=
</varname>.
</para></listitem>
2013 <term><varname>SMTPServers=
</varname></term>
2015 <listitem><para>Similar to the
<varname>DNS=
</varname> setting described above, this
2016 setting configures whether and what SMTP server information shall be emitted as part of
2017 the DHCP lease. The same syntax, propagation semantics and defaults apply as for
2018 <varname>DNS=
</varname>.
</para></listitem>
2022 <term><varname>LPRServers=
</varname></term>
2024 <listitem><para>Similar to the
<varname>DNS=
</varname> setting described above, this
2025 setting configures whether and what LPR (line printer) server information shall be emitted
2026 as part of the DHCP lease. The same syntax, propagation semantics and defaults apply as for
2027 <varname>DNS=
</varname>.
</para></listitem>
2031 <term><varname>EmitRouter=
</varname></term>
2033 <listitem><para>Similar to the
<varname>EmitDNS=
</varname>
2034 setting described above, this setting configures whether the
2035 DHCP lease should contain the router option. The same syntax,
2036 propagation semantics and defaults apply as for
2037 <varname>EmitDNS=
</varname>.
</para></listitem>
2041 <term><varname>EmitTimezone=
</varname></term>
2042 <term><varname>Timezone=
</varname></term>
2044 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2045 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2046 <varname>Timezone=
</varname> setting takes a timezone string
2047 (such as
<literal>Europe/Berlin
</literal> or
2048 <literal>UTC
</literal>) to pass to clients. If no explicit
2049 timezone is set, the system timezone of the local host is
2050 propagated, as determined by the
2051 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2055 <term><varname>SendOption=
</varname></term>
2057 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2058 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2059 The option number is an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
2060 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2061 <literal>string
</literal>. Special characters in the data string may be escaped using
2062 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2063 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2064 then all options specified earlier are cleared. Defaults to unset.
</para>
2069 <term><varname>SendVendorOption=
</varname></term>
2071 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2072 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2073 The option number is an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
2074 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2075 <literal>string
</literal>. Special characters in the data string may be escaped using
2076 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2077 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2078 then all options specified earlier are cleared. Defaults to unset.
</para>
2086 <title>[IPv6PrefixDelegation] Section Options
</title>
2087 <para>The
<literal>[IPv6PrefixDelegation]
</literal> section contains
2088 settings for sending IPv6 Router Advertisements and whether to act as
2089 a router, if enabled via the
<varname>IPv6PrefixDelegation=
</varname>
2090 option described above. IPv6 network prefixes are defined with one or
2091 more
<literal>[IPv6Prefix]
</literal> sections.
</para>
2093 <variablelist class='network-directives'
>
2096 <term><varname>Managed=
</varname></term>
2097 <term><varname>OtherInformation=
</varname></term>
2099 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2100 addresses on the network link when
<varname>Managed=
</varname>
2101 is set to
<literal>true
</literal> or if only additional network
2102 information can be obtained via DHCPv6 for the network link when
2103 <varname>OtherInformation=
</varname> is set to
2104 <literal>true
</literal>. Both settings default to
2105 <literal>false
</literal>, which means that a DHCPv6 server is not being
2106 used.
</para></listitem>
2110 <term><varname>RouterLifetimeSec=
</varname></term>
2112 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. If set,
2113 this host also announces itself in Router Advertisements as an IPv6
2114 router for the network link. When unset, the host is not acting as a router.
</para>
2119 <term><varname>RouterPreference=
</varname></term>
2121 <listitem><para>Configures IPv6 router preference if
2122 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2123 <literal>high
</literal>,
<literal>medium
</literal> and
2124 <literal>low
</literal>, with
<literal>normal
</literal> and
2125 <literal>default
</literal> added as synonyms for
2126 <literal>medium
</literal> just to make configuration easier. See
2127 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2128 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2132 <term><varname>EmitDNS=
</varname></term>
2133 <term><varname>DNS=
</varname></term>
2135 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses
2136 that are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is
2137 true.
<varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that
2138 case the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS
2139 servers are read from the
<literal>[Network]
</literal> section. If the
2140 <literal>[Network]
</literal> section does not contain any DNS servers either, DNS servers from
2141 the uplink with the highest priority default route are used. When
<varname>EmitDNS=
</varname>
2142 is false, no DNS server information is sent in Router Advertisement messages.
2143 <varname>EmitDNS=
</varname> defaults to true.
2148 <term><varname>EmitDomains=
</varname></term>
2149 <term><varname>Domains=
</varname></term>
2151 <listitem><para>A list of DNS search domains distributed via Router
2152 Advertisement messages when
<varname>EmitDomains=
</varname> is true. If
2153 <varname>Domains=
</varname> is empty, DNS search domains are read from the
2154 <literal>[Network]
</literal> section. If the
<literal>[Network]
</literal>
2155 section does not contain any DNS search domains either, DNS search
2156 domains from the uplink with the highest priority default route are
2157 used. When
<varname>EmitDomains=
</varname> is false, no DNS search domain
2158 information is sent in Router Advertisement messages.
2159 <varname>EmitDomains=
</varname> defaults to true.
2164 <term><varname>DNSLifetimeSec=
</varname></term>
2166 <listitem><para>Lifetime in seconds for the DNS server addresses listed
2167 in
<varname>DNS=
</varname> and search domains listed in
2168 <varname>Domains=
</varname>.
</para></listitem>
2175 <title>[IPv6Prefix] Section Options
</title>
2176 <para>One or more
<literal>[IPv6Prefix]
</literal> sections contain the IPv6
2177 prefixes that are announced via Router Advertisements. See
2178 <ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink>
2179 for further details.
</para>
2181 <variablelist class='network-directives'
>
2184 <term><varname>AddressAutoconfiguration=
</varname></term>
2185 <term><varname>OnLink=
</varname></term>
2187 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2188 autoconfigured with this prefix and whether the prefix can be used for
2189 onlink determination. Both settings default to
<literal>true
</literal>
2190 in order to ease configuration.
2195 <term><varname>Prefix=
</varname></term>
2197 <listitem><para>The IPv6 prefix that is to be distributed to hosts.
2198 Similarly to configuring static IPv6 addresses, the setting is
2199 configured as an IPv6 prefix and its prefix length, separated by a
2200 <literal>/
</literal> character. Use multiple
2201 <literal>[IPv6Prefix]
</literal> sections to configure multiple IPv6
2202 prefixes since prefix lifetimes, address autoconfiguration and onlink
2203 status may differ from one prefix to another.
</para></listitem>
2207 <term><varname>PreferredLifetimeSec=
</varname></term>
2208 <term><varname>ValidLifetimeSec=
</varname></term>
2210 <listitem><para>Preferred and valid lifetimes for the prefix measured in
2211 seconds.
<varname>PreferredLifetimeSec=
</varname> defaults to
604800
2212 seconds (one week) and
<varname>ValidLifetimeSec=
</varname> defaults
2213 to
2592000 seconds (
30 days).
</para></listitem>
2217 <term><varname>Assign=
</varname></term>
2218 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2225 <title>[IPv6RoutePrefix] Section Options
</title>
2226 <para>One or more
<literal>[IPv6RoutePrefix]
</literal> sections contain the IPv6
2227 prefix routes that are announced via Router Advertisements. See
2228 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2229 for further details.
</para>
2231 <variablelist class='network-directives'
>
2234 <term><varname>Route=
</varname></term>
2236 <listitem><para>The IPv6 route that is to be distributed to hosts.
2237 Similarly to configuring static IPv6 routes, the setting is
2238 configured as an IPv6 prefix routes and its prefix route length,
2239 separated by a
<literal>/
</literal> character. Use multiple
2240 <literal>[IPv6PrefixRoutes]
</literal> sections to configure multiple IPv6
2241 prefix routes.
</para></listitem>
2245 <term><varname>LifetimeSec=
</varname></term>
2247 <listitem><para>Lifetime for the route prefix measured in
2248 seconds.
<varname>LifetimeSec=
</varname> defaults to
604800 seconds (one week).
2256 <title>[Bridge] Section Options
</title>
2257 <para>The
<literal>[Bridge]
</literal> section accepts the
2258 following keys.
</para>
2259 <variablelist class='network-directives'
>
2261 <term><varname>UnicastFlood=
</varname></term>
2263 <para>Takes a boolean. Controls whether the bridge should flood
2264 traffic for which an FDB entry is missing and the destination
2265 is unknown through this port. When unset, the kernel's default will be used.
2270 <term><varname>MulticastFlood=
</varname></term>
2272 <para>Takes a boolean. Controls whether the bridge should flood
2273 traffic for which an MDB entry is missing and the destination
2274 is unknown through this port. When unset, the kernel's default will be used.
2279 <term><varname>MulticastToUnicast=
</varname></term>
2281 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
2282 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
2283 When unset, the kernel's default will be used.
2288 <term><varname>NeighborSuppression=
</varname></term>
2290 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
2291 this port. When unset, the kernel's default will be used.
2296 <term><varname>Learning=
</varname></term>
2298 <para>Takes a boolean. Configures whether MAC address learning is enabled for
2299 this port. When unset, the kernel's default will be used.
2304 <term><varname>HairPin=
</varname></term>
2306 <para>Takes a boolean. Configures whether traffic may be sent back
2307 out of the port on which it was received. When this flag is false, and the bridge
2308 will not forward traffic back out of the receiving port.
2309 When unset, the kernel's default will be used.
</para>
2313 <term><varname>UseBPDU=
</varname></term>
2315 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
2316 processed by the bridge port. When unset, the kernel's default will be used.
</para>
2320 <term><varname>FastLeave=
</varname></term>
2322 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
2323 traffic on a port that receives an IGMP Leave message. It is only used with
2324 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
2328 <term><varname>AllowPortToBeRoot=
</varname></term>
2330 <para>Takes a boolean. Configures whether a given port is allowed to
2331 become a root port. Only used when STP is enabled on the bridge.
2332 When unset, the kernel's default will be used.
</para>
2336 <term><varname>ProxyARP=
</varname></term>
2338 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
2339 When unset, the kernel's default will be used.
</para>
2343 <term><varname>ProxyARPWiFi=
</varname></term>
2345 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
2346 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
2347 When unset, the kernel's default will be used.
</para>
2351 <term><varname>MulticastRouter=
</varname></term>
2353 <para>Configures this port for having multicast routers attached. A port with a multicast
2354 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
2355 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
2356 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
2357 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
2358 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
2362 <term><varname>Cost=
</varname></term>
2364 <para>Sets the
"cost" of sending packets of this interface.
2365 Each port in a bridge may have a different speed and the cost
2366 is used to decide which link to use. Faster interfaces
2367 should have lower costs. It is an integer value between
1 and
2372 <term><varname>Priority=
</varname></term>
2374 <para>Sets the
"priority" of sending packets on this interface.
2375 Each port in a bridge may have a different priority which is used
2376 to decide which link to use. Lower value means higher priority.
2377 It is an integer value between
0 to
63. Networkd does not set any
2378 default, meaning the kernel default value of
32 is used.
</para>
2384 <title>[BridgeFDB] Section Options
</title>
2385 <para>The
<literal>[BridgeFDB]
</literal> section manages the
2386 forwarding database table of a port and accepts the following
2387 keys. Specify several
<literal>[BridgeFDB]
</literal> sections to
2388 configure several static MAC table entries.
</para>
2390 <variablelist class='network-directives'
>
2392 <term><varname>MACAddress=
</varname></term>
2394 <para>As in the
<literal>[Network]
</literal> section. This
2395 key is mandatory.
</para>
2399 <term><varname>Destination=
</varname></term>
2401 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
2405 <term><varname>VLANId=
</varname></term>
2407 <para>The VLAN ID for the new static MAC table entry. If
2408 omitted, no VLAN ID information is appended to the new static MAC
2413 <term><varname>VNI=
</varname></term>
2415 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
2416 the remote VXLAN tunnel endpoint. Takes a number in the range
1-
16777215.
2417 Defaults to unset.
</para>
2421 <term><varname>AssociatedWith=
</varname></term>
2423 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
2424 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
2425 <literal>use
</literal> means the address is in use. User space can use this option to
2426 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
2427 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
2428 means the address is associated with master devices fdb.
<literal>router
</literal> means
2429 the destination address is associated with a router. Note that it's valid if the referenced
2430 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
2437 <title>[LLDP] Section Options
</title>
2438 <para>The
<literal>[LLDP]
</literal> section manages the Link Layer Discovery Protocol (LLDP) and accepts the
2439 following keys.
</para>
2440 <variablelist class='network-directives'
>
2442 <term><varname>MUDURL=
</varname></term>
2444 <para>Controls support for Ethernet LLDP packet's Manufacturer Usage Description (MUD). MUD is an embedded software
2445 standard defined by the IETF that allows IoT Device makers to advertise device specifications, including the intended
2446 communication patterns for their device when it connects to the network. The network can then use this intent to author
2447 a context-specific access policy, so the device functions only within those parameters. Takes an URL of length up to
255
2448 characters. A superficial verification that the string is a valid URL
2449 will be performed. See
2450 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink> for details. The MUD URL received
2451 from the LLDP packets will be saved at the state files and can be read via
2452 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
2459 <title>[CAN] Section Options
</title>
2460 <para>The
<literal>[CAN]
</literal> section manages the Controller Area Network (CAN bus) and accepts the
2461 following keys.
</para>
2462 <variablelist class='network-directives'
>
2464 <term><varname>BitRate=
</varname></term>
2466 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
2467 be used here. Takes a number in the range
1.
.4294967295.
</para>
2471 <term><varname>SamplePoint=
</varname></term>
2473 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
2474 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>).
</para>
2478 <term><varname>DataBitRate=
</varname></term>
2479 <term><varname>DataSamplePoint=
</varname></term>
2481 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
2482 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
2486 <term><varname>FDMode=
</varname></term>
2488 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
2489 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
2490 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys.
</para>
2494 <term><varname>FDNonISO=
</varname></term>
2496 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
2497 interface. When unset, the kernel's default will be used.
</para>
2501 <term><varname>RestartSec=
</varname></term>
2503 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
2504 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
2505 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
2506 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
2507 automatic restart off. By default automatic restart is disabled.
</para>
2511 <term><varname>Termination=
</varname></term>
2513 <para>Takes a boolean. When
<literal>yes
</literal>, the termination resistor will be selected for
2514 the bias network. When unset, the kernel's default will be used.
</para>
2518 <term><varname>TripleSampling=
</varname></term>
2520 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
2521 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
2525 <term><varname>ListenOnly=
</varname></term>
2527 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
2528 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
2529 bit. Listen-only mode is important to debug CAN networks without interfering with the
2530 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
2538 <title>[QDisc] Section Options
</title>
2539 <para>The
<literal>[QDisc]
</literal> section manages the traffic control queueing discipline (qdisc).
</para>
2541 <variablelist class='network-directives'
>
2543 <term><varname>Parent=
</varname></term>
2545 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
2546 or
<literal>ingress
</literal>. This is mandatory.
</para>
2550 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2555 <title>[NetworkEmulator] Section Options
</title>
2556 <para>The
<literal>[NetworkEmulator]
</literal> section manages the queueing discipline (qdisc) of
2557 the network emulator. It can be used to configure the kernel packet scheduler and simulate packet
2558 delay and loss for UDP or TCP applications, or limit the bandwidth usage of a particular service to
2559 simulate internet connections.
</para>
2561 <variablelist class='network-directives'
>
2562 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2563 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2566 <term><varname>DelaySec=
</varname></term>
2568 <para>Specifies the fixed amount of delay to be added to all packets going out of the
2569 interface. Defaults to unset.
</para>
2574 <term><varname>DelayJitterSec=
</varname></term>
2576 <para>Specifies the chosen delay to be added to the packets outgoing to the network
2577 interface. Defaults to unset.
</para>
2582 <term><varname>PacketLimit=
</varname></term>
2584 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
2585 An unsigned integer ranges
0 to
4294967294. Defaults to
1000.
</para>
2590 <term><varname>LossRate=
</varname></term>
2592 <para>Specifies an independent loss probability to be added to the packets outgoing from the
2593 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
2598 <term><varname>DuplicateRate=
</varname></term>
2600 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
2601 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
2608 <title>[TokenBucketFilter] Section Options
</title>
2609 <para>The
<literal>[TokenBucketFilter]
</literal> section manages the queueing discipline (qdisc) of
2610 token bucket filter (tbf).
</para>
2612 <variablelist class='network-directives'
>
2613 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2614 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2617 <term><varname>LatencySec=
</varname></term>
2619 <para>Specifies the latency parameter, which specifies the maximum amount of time a
2620 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
2625 <term><varname>LimitSize=
</varname></term>
2627 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
2628 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
2629 respectively, to the base of
1000. Defaults to unset.
</para>
2634 <term><varname>Burst=
</varname></term>
2636 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
2637 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
2638 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1000. Defaults to
2644 <term><varname>Rate=
</varname></term>
2646 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
2647 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
2648 Defaults to unset.
</para>
2653 <term><varname>MPUBytes=
</varname></term>
2655 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
2656 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
2657 Megabytes, or Gigabytes, respectively, to the base of
1000. Defaults to zero.
</para>
2662 <term><varname>PeakRate=
</varname></term>
2664 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
2665 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
2666 1000. Defaults to unset.
</para>
2671 <term><varname>MTUBytes=
</varname></term>
2673 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
2674 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1000.
2675 Defaults to unset.
</para>
2682 <title>[PIE] Section Options
</title>
2683 <para>The
<literal>[PIE]
</literal> section manages the queueing discipline
2684 (qdisc) of Proportional Integral controller-Enhanced (PIE).
</para>
2686 <variablelist class='network-directives'
>
2687 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2688 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2691 <term><varname>PacketLimit=
</varname></term>
2693 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
2694 dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2701 <title>[StochasticFairBlue] Section Options
</title>
2702 <para>The
<literal>[StochasticFairBlue]
</literal> section manages the queueing discipline
2703 (qdisc) of stochastic fair blue (sfb).
</para>
2705 <variablelist class='network-directives'
>
2706 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2707 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2710 <term><varname>PacketLimit=
</varname></term>
2712 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
2713 dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2720 <title>[StochasticFairnessQueueing] Section Options
</title>
2721 <para>The
<literal>[StochasticFairnessQueueing]
</literal> section manages the queueing discipline
2722 (qdisc) of stochastic fairness queueing (sfq).
</para>
2724 <variablelist class='network-directives'
>
2725 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2726 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2729 <term><varname>PerturbPeriodSec=
</varname></term>
2731 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
2738 <title>[BFIFO] Section Options
</title>
2739 <para>The
<literal>[BFIFO]
</literal> section manages the queueing discipline (qdisc) of
2740 Byte limited Packet First In First Out (bfifo).
</para>
2742 <variablelist class='network-directives'
>
2743 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2744 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2747 <term><varname>LimitSize=
</varname></term>
2749 <para>Specifies the hard limit on the FIFO size in bytes. The size limit (a buffer size) to prevent it
2750 from overflowing in case it is unable to dequeue packets as quickly as it receives them. When this limit
2751 is reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed as
2752 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
2759 <title>[PFIFO] Section Options
</title>
2760 <para>The
<literal>[PFIFO]
</literal> section manages the queueing discipline (qdisc) of
2761 Packet First In First Out (pfifo).
</para>
2763 <variablelist class='network-directives'
>
2764 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2765 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2768 <term><varname>PacketLimit=
</varname></term>
2770 <para>Specifies the hard limit on the FIFO size in number of packets. The size limit (a buffer size) to prevent it
2771 from overflowing in case it is unable to dequeue packets as quickly as it receives them. When this limit is reached,
2772 incoming packets are dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2779 <title>[PFIFOHeadDrop] Section Options
</title>
2780 <para>The
<literal>[PFIFOHeadDrop]
</literal> section manages the queueing discipline (qdisc) of
2781 Packet First In First Out Head Drop (pfifo_head_drop).
</para>
2783 <variablelist class='network-directives'
>
2784 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2785 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2788 <term><varname>PacketLimit=
</varname></term>
2790 <para>As in
<literal>[PFIFO]
</literal> section.
</para></listitem>
2796 <title>[PFIFOFast] Section Options
</title>
2797 <para>The
<literal>[PFIFOFast]
</literal> section manages the queueing discipline (qdisc) of
2798 Packet First In First Out Fast (pfifo_fast).
</para>
2800 <variablelist class='network-directives'
>
2801 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2802 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2807 <title>[CAKE] Section Options
</title>
2808 <para>The
<literal>[CAKE]
</literal> section manages the queueing discipline (qdisc) of
2809 Common Applications Kept Enhanced (CAKE).
</para>
2811 <variablelist class='network-directives'
>
2812 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2813 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2816 <term><varname>Overhead=
</varname></term>
2818 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative.
2819 Takes an integer ranges -
64 to
256. Defaults to unset and kernel's default is used.
</para>
2824 <term><varname>Bandwidth=
</varname></term>
2826 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
2827 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
2828 unset and kernel's default is used.
</para>
2835 <title>[ControlledDelay] Section Options
</title>
2836 <para>The
<literal>[ControlledDelay]
</literal> section manages the queueing discipline (qdisc) of
2837 controlled delay (CoDel).
</para>
2839 <variablelist class='network-directives'
>
2840 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2841 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2844 <term><varname>PacketLimit=
</varname></term>
2846 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
2847 dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2852 <term><varname>TargetSec=
</varname></term>
2854 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
2855 Defaults to unset and kernel's default is used.
</para>
2860 <term><varname>IntervalSec=
</varname></term>
2862 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
2863 become too stale. Defaults to unset and kernel's default is used.
</para>
2868 <term><varname>ECN=
</varname></term>
2870 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
2871 unset and kernel's default is used.
</para>
2876 <term><varname>CEThresholdSec=
</varname></term>
2878 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
2879 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
2886 <title>[DeficitRoundRobinScheduler] Section Options
</title>
2887 <para>The
<literal>[DeficitRoundRobinScheduler]
</literal> section manages the queueing discipline (qdisc) of
2888 Deficit Round Robin Scheduler (DRR).
</para>
2890 <variablelist class='network-directives'
>
2891 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2892 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2897 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
2898 <para>The
<literal>[DeficitRoundRobinSchedulerClass]
</literal> section manages the traffic control class of
2899 Deficit Round Robin Scheduler (DRR).
</para>
2901 <variablelist class='network-directives'
>
2902 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
2903 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
2906 <term><varname>Quantum=
</varname></term>
2908 <para>Specifies the amount of bytes a flow is allowed to dequeue before the
2909 scheduler moves to the next class. An unsigned integer ranges
1 to
4294967294.
2910 Defaults to the MTU of the interface.
</para>
2918 <title>[GenericRandomEarlyDetection] Section Options
</title>
2919 <para>The
<literal>[GenericRandomEarlyDetection]
</literal> section manages the queueing discipline
2920 (qdisc) of Generic Random Early Detection (GRED).
</para>
2922 <variablelist class='network-directives'
>
2923 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2924 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2927 <term><varname>VirtualQueues=
</varname></term>
2929 <para>Specifies the number of virtual queues. Takes a integer in the range
1-
16. Defaults to unset and kernel's default is used.
</para>
2934 <term><varname>DefaultVirtualQueue=
</varname></term>
2936 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
2937 Defaults to unset and kernel's default is used.
</para>
2942 <term><varname>GenericRIO=
</varname></term>
2944 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
2945 unset and kernel's default is used.
</para>
2952 <title>[FairQueueingControlledDelay] Section Options
</title>
2953 <para>The
<literal>[FairQueueingControlledDelay]
</literal> section manages the queueing discipline
2954 (qdisc) of fair queuing controlled delay (FQ-CoDel).
</para>
2956 <variablelist class='network-directives'
>
2957 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2958 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2961 <term><varname>PacketLimit=
</varname></term>
2963 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
2964 dropped. Defaults to unset and kernel's default is used.
</para>
2969 <term><varname>MemoryLimit=
</varname></term>
2971 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
2972 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
2973 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
2978 <term><varname>Flows=
</varname></term>
2980 <para>Specifies the number of flows into which the incoming packets are classified.
2981 Defaults to unset and kernel's default is used.
</para>
2986 <term><varname>TargetSec=
</varname></term>
2988 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
2989 Defaults to unset and kernel's default is used.
</para>
2994 <term><varname>IntervalSec=
</varname></term>
2996 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
2997 become too stale. Defaults to unset and kernel's default is used.
</para>
3002 <term><varname>Quantum=
</varname></term>
3004 <para>Specifies the number of bytes used as 'deficit' in the fair queuing algorithmtimespan.
3005 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3006 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
3011 <term><varname>ECN=
</varname></term>
3013 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3014 unset and kernel's default is used.
</para>
3019 <term><varname>CEThresholdSec=
</varname></term>
3021 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3022 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3029 <title>[FairQueueing] Section Options
</title>
3030 <para>The
<literal>[FairQueueing]
</literal> section manages the queueing discipline
3031 (qdisc) of fair queue traffic policing (FQ).
</para>
3033 <variablelist class='network-directives'
>
3034 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3035 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3038 <term><varname>PacketLimit=
</varname></term>
3040 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
3041 dropped. Defaults to unset and kernel's default is used.
</para>
3046 <term><varname>FlowLimit=
</varname></term>
3048 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
3049 unset and kernel's default is used.
</para>
3054 <term><varname>Quantum=
</varname></term>
3056 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
3057 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3058 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
3059 default is used.
</para>
3064 <term><varname>InitialQuantum=
</varname></term>
3066 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
3067 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
3068 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3069 kernel's default is used.
</para>
3074 <term><varname>MaximumRate=
</varname></term>
3076 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
3077 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3078 1000. Defaults to unset and kernel's default is used.
</para>
3083 <term><varname>Buckets=
</varname></term>
3085 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
3086 kernel's default is used.
</para>
3091 <term><varname>OrphanMask=
</varname></term>
3093 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
3094 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
3095 kernel's default is used.
</para>
3100 <term><varname>Pacing=
</varname></term>
3102 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
3103 default is used.
</para>
3108 <term><varname>CEThresholdSec=
</varname></term>
3110 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3111 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3118 <title>[TrivialLinkEqualizer] Section Options
</title>
3119 <para>The
<literal>[TrivialLinkEqualizer]
</literal> section manages the queueing discipline (qdisc) of
3120 trivial link equalizer (teql).
</para>
3122 <variablelist class='network-directives'
>
3123 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3124 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3127 <term><varname>Id=
</varname></term>
3129 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
3130 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
3131 <constant>max_equalizers=N+
1</constant> option must be loaded before
3132 <command>systemd-networkd
</command> is started.
</para>
3139 <title>[HierarchyTokenBucket] Section Options
</title>
3140 <para>The
<literal>[HierarchyTokenBucket]
</literal> section manages the queueing discipline (qdisc) of
3141 hierarchy token bucket (htb).
</para>
3143 <variablelist class='network-directives'
>
3144 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3145 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3148 <term><varname>DefaultClass=
</varname></term>
3150 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
3151 to the class. Defaults to unset.
</para>
3158 <title>[HierarchyTokenBucketClass] Section Options
</title>
3159 <para>The
<literal>[HierarchyTokenBucketClass]
</literal> section manages the traffic control class of
3160 hierarchy token bucket (htb).
</para>
3162 <variablelist class='network-directives'
>
3163 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3164 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3167 <term><varname>Priority=
</varname></term>
3169 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
3170 priority field are tried for packets first. This setting is mandatory.
</para>
3175 <term><varname>Rate=
</varname></term>
3177 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
3178 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
3179 to the base of
1000. This setting is mandatory.
</para>
3184 <term><varname>CeilRate=
</varname></term>
3186 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
3187 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
3188 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
3196 <title>[HeavyHitterFilter] Section Options
</title>
3197 <para>The
<literal>[HeavyHitterFilter]
</literal> section manages the queueing discipline
3198 (qdisc) of Heavy Hitter Filter (hhf).
</para>
3200 <variablelist class='network-directives'
>
3201 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3202 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3205 <term><varname>PacketLimit=
</varname></term>
3207 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
3208 dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
3215 <title>[BridgeVLAN] Section Options
</title>
3216 <para>The
<literal>[BridgeVLAN]
</literal> section manages the VLAN ID configuration of a bridge port and accepts
3217 the following keys. Specify several
<literal>[BridgeVLAN]
</literal> sections to configure several VLAN entries.
3218 The
<varname>VLANFiltering=
</varname> option has to be enabled, see
<literal>[Bridge]
</literal> section in
3219 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
3221 <variablelist class='network-directives'
>
3223 <term><varname>VLAN=
</varname></term>
3225 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. VLAN IDs are valid
3226 from
1 to
4094.
</para>
3230 <term><varname>EgressUntagged=
</varname></term>
3232 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
3233 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
3234 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
3238 <term><varname>PVID=
</varname></term>
3240 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
3241 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
3242 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
3249 <title>Examples
</title>
3251 <title>Static network configuration
</title>
3253 <programlisting># /etc/systemd/network/
50-static.network
3258 Address=
192.168.0.15/
24
3259 Gateway=
192.168.0.1</programlisting>
3261 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
3262 specified gateway will be used for a default route.
</para>
3266 <title>DHCP on ethernet links
</title>
3268 <programlisting># /etc/systemd/network/
80-dhcp.network
3273 DHCP=yes
</programlisting>
3275 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
3276 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
3280 <title>IPv6 Prefix Delegation
</title>
3282 <programlisting># /etc/systemd/network/
55-ipv6-pd-upstream.network
3287 DHCP=ipv6
</programlisting>
3289 <programlisting># /etc/systemd/network/
56-ipv6-pd-downstream.network
3294 IPv6PrefixDelegation=dhcpv6
</programlisting>
3296 <para>This will enable IPv6 PD on the interface enp1s0 as an upstream interface where the
3297 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
</para>
3301 <title>A bridge with two enslaved links
</title>
3303 <programlisting># /etc/systemd/network/
25-bridge-static.network
3308 Address=
192.168.0.15/
24
3310 DNS=
192.168.0.1</programlisting>
3312 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
3317 Bridge=bridge0
</programlisting>
3319 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
3324 Bridge=bridge0
</programlisting>
3326 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
3327 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
3328 and network assigned, and a default route via the specified gateway will be
3329 added. The specified DNS server will be added to the global list of DNS resolvers.
3337 # /etc/systemd/network/
20-bridge-slave-interface-vlan.network
3353 EgressUntagged=
300-
400</programlisting>
3355 <para>This overrides the configuration specified in the previous example for the
3356 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
3357 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
3358 untagged when they leave on this interface. Untagged packets which arrive on this
3359 interface will be assigned VLAN ID
42.
</para>
3363 <title>Various tunnels
</title>
3365 <programlisting>/etc/systemd/network/
25-tunnels.network
3376 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
3382 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
3388 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
3394 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
3400 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
3401 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
3405 <title>A bond device
</title>
3407 <programlisting># /etc/systemd/network/
30-bond1.network
3415 <programlisting># /etc/systemd/network/
30-bond1.netdev
3421 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
3423 MACAddress=
52:
54:
00:e9:
64:
41
3429 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
3431 MACAddress=
52:
54:
00:e9:
64:
42
3437 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
3438 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
3439 will be used to acquire an address.
</para>
3443 <title>Virtual Routing and Forwarding (VRF)
</title>
3444 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
3445 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
3446 within the routing table defined during VRF creation. For kernels before
4.8 traffic
3447 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
3449 <programlisting># /etc/systemd/network/
25-vrf.network
3459 <title>MacVTap
</title>
3460 <para>This brings up a network interface
<literal>macvtap-test
</literal>
3461 and attaches it to
<literal>enp0s25
</literal>.
</para>
3462 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
3467 MACVTAP=macvtap-test
3472 <title>A Xfrm interface with physical underlying device.
</title>
3474 <programlisting># /etc/systemd/network/
27-xfrm.netdev
3479 InterfaceId=
7</programlisting>
3481 <programlisting># /etc/systemd/network/
27-eth0.network
3486 Xfrm=xfrm0
</programlisting>
3488 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
3489 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
3490 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
3496 <title>See Also
</title>
3498 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
3499 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
3500 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
3501 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
3502 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob