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.
836 <term><varname>IgnoreCarrierLoss=
</varname></term>
838 <para>A boolean. Allows networkd to retain both the static and dynamic configuration of the
839 interface even if its carrier is lost. Defaults to false.
844 <term><varname>Xfrm=
</varname></term>
846 <para>The name of the xfrm to create on the link. See
847 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
848 This option may be specified more than once.
</para>
852 <term><varname>KeepConfiguration=
</varname></term>
854 <para>Takes a boolean or one of
<literal>static
</literal>,
<literal>dhcp-on-stop
</literal>,
855 <literal>dhcp
</literal>. When
<literal>static
</literal>,
<command>systemd-networkd
</command>
856 will not drop static addresses and routes on starting up process. When set to
857 <literal>dhcp-on-stop
</literal>,
<command>systemd-networkd
</command> will not drop addresses
858 and routes on stopping the daemon. When
<literal>dhcp
</literal>,
859 the addresses and routes provided by a DHCP server will never be dropped even if the DHCP
860 lease expires. This is contrary to the DHCP specification, but may be the best choice if,
861 e.g., the root filesystem relies on this connection. The setting
<literal>dhcp
</literal>
862 implies
<literal>dhcp-on-stop
</literal>, and
<literal>yes
</literal> implies
863 <literal>dhcp
</literal> and
<literal>static
</literal>. Defaults to
<literal>no
</literal>.
873 <title>[Address] Section Options
</title>
875 <para>An
<literal>[Address]
</literal> section accepts the
876 following keys. Specify several
<literal>[Address]
</literal>
877 sections to configure several addresses.
</para>
879 <variablelist class='network-directives'
>
881 <term><varname>Address=
</varname></term>
883 <para>As in the
<literal>[Network]
</literal> section. This key is mandatory. Each
884 <literal>[Address]
</literal> section can contain one
<varname>Address=
</varname> setting.
</para>
888 <term><varname>Peer=
</varname></term>
890 <para>The peer address in a point-to-point connection.
891 Accepts the same format as the
<varname>Address=
</varname>
896 <term><varname>Broadcast=
</varname></term>
898 <para>The broadcast address, which must be in the format
900 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
901 This key only applies to IPv4 addresses. If it is not
902 given, it is derived from the
<varname>Address=
</varname>
907 <term><varname>Label=
</varname></term>
909 <para>An address label.
</para>
913 <term><varname>PreferredLifetime=
</varname></term>
915 <para>Allows the default
"preferred lifetime" of the address to be overridden.
916 Only three settings are accepted:
<literal>forever
</literal> or
<literal>infinity
</literal>
917 which is the default and means that the address never expires, and
<literal>0</literal> which means
918 that the address is considered immediately
"expired" and will not be used,
919 unless explicitly requested. A setting of PreferredLifetime=
0 is useful for
920 addresses which are added to be used only by a specific application,
921 which is then configured to use them explicitly.
</para>
925 <term><varname>Scope=
</varname></term>
927 <para>The scope of the address, which can be
<literal>global
</literal>,
928 <literal>link
</literal> or
<literal>host
</literal> or an unsigned integer ranges
0 to
255.
929 Defaults to
<literal>global
</literal>.
</para>
933 <term><varname>HomeAddress=
</varname></term>
935 <para>Takes a boolean. Designates this address the
"home address" as defined in
936 <ulink url=
"https://tools.ietf.org/html/rfc6275">RFC
6275</ulink>.
937 Supported only on IPv6. Defaults to false.
</para>
941 <term><varname>DuplicateAddressDetection=
</varname></term>
943 <para>Takes one of
<literal>ipv4
</literal>,
<literal>ipv6
</literal>,
944 <literal>both
</literal>,
<literal>none
</literal>. When
<literal>ipv4
</literal>,
945 performs IPv4 Duplicate Address Detection. See
946 <ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5224</ulink>.
947 When
<literal>ipv6
</literal>, performs IPv6 Duplicate Address Detection. See
948 <ulink url=
"https://tools.ietf.org/html/rfc4862">RFC
4862</ulink>.
949 Defaults to
<literal>ipv6
</literal>.
</para>
953 <term><varname>ManageTemporaryAddress=
</varname></term>
955 <para>Takes a boolean. If true the kernel manage temporary addresses created
956 from this one as template on behalf of Privacy Extensions
957 <ulink url=
"https://tools.ietf.org/html/rfc3041">RFC
3041</ulink>. For this to become
958 active, the use_tempaddr sysctl setting has to be set to a value greater than zero.
959 The given address needs to have a prefix length of
64. This flag allows using privacy
960 extensions in a manually configured network, just like if stateless auto-configuration
961 was active. Defaults to false.
</para>
965 <term><varname>AddPrefixRoute=
</varname></term>
967 <para>Takes a boolean. When true, the prefix route for the address is automatically added.
968 Defaults to true.
</para>
972 <term><varname>AutoJoin=
</varname></term>
974 <para>Takes a boolean. Joining multicast group on ethernet level via
975 <command>ip maddr
</command> command would not work if we have an Ethernet switch that does
976 IGMP snooping since the switch would not replicate multicast packets on ports that did not
977 have IGMP reports for the multicast addresses. Linux vxlan interfaces created via
978 <command>ip link add vxlan
</command> or networkd's netdev kind vxlan have the group option
979 that enables then to do the required join. By extending ip address command with option
980 <literal>autojoin
</literal> we can get similar functionality for openvswitch (OVS) vxlan
981 interfaces as well as other tunneling mechanisms that need to receive multicast traffic.
982 Defaults to
<literal>no
</literal>.
</para>
989 <title>[Neighbor] Section Options
</title>
990 <para>A
<literal>[Neighbor]
</literal> section accepts the
991 following keys. The neighbor section adds a permanent, static
992 entry to the neighbor table (IPv6) or ARP table (IPv4) for
993 the given hardware address on the links matched for the network.
994 Specify several
<literal>[Neighbor]
</literal> sections to configure
995 several static neighbors.
</para>
997 <variablelist class='network-directives'
>
999 <term><varname>Address=
</varname></term>
1001 <para>The IP address of the neighbor.
</para>
1005 <term><varname>LinkLayerAddress=
</varname></term>
1007 <para>The link layer address (MAC address or IP address) of the neighbor.
</para>
1014 <title>[IPv6AddressLabel] Section Options
</title>
1016 <para>An
<literal>[IPv6AddressLabel]
</literal> section accepts the
1017 following keys. Specify several
<literal>[IPv6AddressLabel]
</literal>
1018 sections to configure several address labels. IPv6 address labels are
1019 used for address selection. See
<ulink url=
"https://tools.ietf.org/html/rfc3484">RFC
3484</ulink>.
1020 Precedence is managed by userspace, and only the label itself is stored in the kernel
</para>
1022 <variablelist class='network-directives'
>
1024 <term><varname>Label=
</varname></term>
1026 <para> The label for the prefix (an unsigned integer) ranges
0 to
4294967294.
1027 0xffffffff is reserved. This key is mandatory.
</para>
1031 <term><varname>Prefix=
</varname></term>
1033 <para>IPv6 prefix is an address with a prefix length, separated by a slash
<literal>/
</literal> character.
1034 This key is mandatory.
</para>
1041 <title>[RoutingPolicyRule] Section Options
</title>
1043 <para>An
<literal>[RoutingPolicyRule]
</literal> section accepts the
1044 following keys. Specify several
<literal>[RoutingPolicyRule]
</literal>
1045 sections to configure several rules.
</para>
1047 <variablelist class='network-directives'
>
1049 <term><varname>TypeOfService=
</varname></term>
1051 <para>Specifies the type of service to match a number between
0 to
255.
</para>
1055 <term><varname>From=
</varname></term>
1057 <para>Specifies the source address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1061 <term><varname>To=
</varname></term>
1063 <para>Specifies the destination address prefix to match. Possibly followed by a slash and the prefix length.
</para>
1067 <term><varname>FirewallMark=
</varname></term>
1069 <para>Specifies the iptables firewall mark value to match (a number between
1 and
4294967295).
</para>
1073 <term><varname>Table=
</varname></term>
1075 <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes
1076 one of
<literal>default
</literal>,
<literal>main
</literal>, and
<literal>local
</literal>,
1077 or a number between
1 and
4294967295. Defaults to
<literal>main
</literal>.
</para>
1081 <term><varname>Priority=
</varname></term>
1083 <para>Specifies the priority of this rule.
<varname>Priority=
</varname> is an unsigned
1084 integer. Higher number means lower priority, and rules get processed in order of increasing number.
</para>
1088 <term><varname>IncomingInterface=
</varname></term>
1090 <para>Specifies incoming device to match. If the interface is loopback, the rule only matches packets originating from this host.
</para>
1094 <term><varname>OutgoingInterface=
</varname></term>
1096 <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>
1100 <term><varname>SourcePort=
</varname></term>
1102 <para>Specifies the source IP port or IP port range match in forwarding information base (FIB) rules.
1103 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1107 <term><varname>DestinationPort=
</varname></term>
1109 <para>Specifies the destination IP port or IP port range match in forwarding information base (FIB) rules.
1110 A port range is specified by the lower and upper port separated by a dash. Defaults to unset.
</para>
1114 <term><varname>IPProtocol=
</varname></term>
1116 <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP protocol name such as
<literal>tcp
</literal>,
1117 <literal>udp
</literal> or
<literal>sctp
</literal>, or IP protocol number such as
<literal>6</literal> for
<literal>tcp
</literal> or
1118 <literal>17</literal> for
<literal>udp
</literal>.
1119 Defaults to unset.
</para>
1123 <term><varname>InvertRule=
</varname></term>
1125 <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.
</para>
1129 <term><varname>Family=
</varname></term>
1131 <para>Takes a special value
<literal>ipv4
</literal>,
<literal>ipv6
</literal>, or
1132 <literal>both
</literal>. By default, the address family is determined by the address
1133 specified in
<varname>To=
</varname> or
<varname>From=
</varname>. If neither
1134 <varname>To=
</varname> nor
<varname>From=
</varname> are specified, then defaults to
1135 <literal>ipv4
</literal>.
</para>
1139 <term><varname>User=
</varname></term>
1141 <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to
1146 <term><varname>SuppressPrefixLength=
</varname></term>
1148 <para>Takes a number
<replaceable>N
</replaceable> in the range
0-
128 and rejects routing
1149 decisions that have a prefix length of
<replaceable>N
</replaceable> or less. Defaults to
1157 <title>[NextHop] Section Options
</title>
1158 <para>The
<literal>[NextHop]
</literal> section accepts the
1159 following keys. Specify several
<literal>[NextHop]
</literal>
1160 sections to configure several nexthop. Nexthop is used to manipulate entries in the kernel's nexthop
1163 <variablelist class='network-directives'
>
1165 <term><varname>Gateway=
</varname></term>
1167 <para>As in the
<literal>[Network]
</literal> section. This is mandatory.
</para>
1171 <term><varname>Id=
</varname></term>
1173 <para>The id of the nexthop (an unsigned integer). If unspecified or '
0' then automatically chosen by kernel.
</para>
1180 <title>[Route] Section Options
</title>
1181 <para>The
<literal>[Route]
</literal> section accepts the
1182 following keys. Specify several
<literal>[Route]
</literal>
1183 sections to configure several routes.
</para>
1185 <variablelist class='network-directives'
>
1187 <term><varname>Gateway=
</varname></term>
1189 <para>Takes the gateway address or special value
<literal>_dhcp
</literal>. If
1190 <literal>_dhcp
</literal>, then the gateway address provided by DHCP (or in the IPv6 case,
1191 provided by IPv6 RA) is used.
</para>
1195 <term><varname>GatewayOnLink=
</varname></term>
1197 <para>Takes a boolean. If set to true, the kernel does not have
1198 to check if the gateway is reachable directly by the current machine (i.e., the kernel does
1199 not need to check if the gateway is attached to the local network), so that we can insert the
1200 route in the kernel table without it being complained about. Defaults to
<literal>no
</literal>.
1205 <term><varname>Destination=
</varname></term>
1207 <para>The destination prefix of the route. Possibly
1208 followed by a slash and the prefix length. If omitted, a
1209 full-length host route is assumed.
</para>
1213 <term><varname>Source=
</varname></term>
1215 <para>The source prefix of the route. Possibly followed by
1216 a slash and the prefix length. If omitted, a full-length
1217 host route is assumed.
</para>
1221 <term><varname>Metric=
</varname></term>
1223 <para>The metric of the route (an unsigned integer).
</para>
1227 <term><varname>IPv6Preference=
</varname></term>
1229 <para>Specifies the route preference as defined in
<ulink
1230 url=
"https://tools.ietf.org/html/rfc4191">RFC4191
</ulink> for Router Discovery messages.
1231 Which can be one of
<literal>low
</literal> the route has a lowest priority,
1232 <literal>medium
</literal> the route has a default priority or
1233 <literal>high
</literal> the route has a highest priority.
</para>
1237 <term><varname>Scope=
</varname></term>
1239 <para>The scope of the route, which can be
<literal>global
</literal>,
<literal>site
</literal>,
1240 <literal>link
</literal>,
<literal>host
</literal>, or
<literal>nowhere
</literal>. For IPv4 route,
1241 defaults to
<literal>host
</literal> if
<varname>Type=
</varname> is
<literal>local
</literal>
1242 or
<literal>nat
</literal>, and
<literal>link
</literal> if
<varname>Type=
</varname> is
1243 <literal>broadcast
</literal>,
<literal>multicast
</literal>, or
<literal>anycast
</literal>.
1244 In other cases, defaults to
<literal>global
</literal>.
</para>
1248 <term><varname>PreferredSource=
</varname></term>
1250 <para>The preferred source address of the route. The address
1251 must be in the format described in
1252 <citerefentry project='man-pages'
><refentrytitle>inet_pton
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
1256 <term><varname>Table=
</varname></term>
1258 <para>The table identifier for the route. Takes
<literal>default
</literal>,
1259 <literal>main
</literal>,
<literal>local
</literal> or a number between
1 and
4294967295.
1260 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1261 If unset and
<varname>Type=
</varname> is
<literal>local
</literal>,
<literal>broadcast
</literal>,
1262 <literal>anycast
</literal>, or
<literal>nat
</literal>, then
<literal>local
</literal> is used.
1263 In other cases, defaults to
<literal>main
</literal>.
1268 <term><varname>Protocol=
</varname></term>
1270 <para>The protocol identifier for the route. Takes a number between
0 and
255 or the special values
1271 <literal>kernel
</literal>,
<literal>boot
</literal>,
<literal>static
</literal>,
1272 <literal>ra
</literal> and
<literal>dhcp
</literal>. Defaults to
<literal>static
</literal>.
1277 <term><varname>Type=
</varname></term>
1279 <para>Specifies the type for the route. Takes one of
<literal>unicast
</literal>,
1280 <literal>local
</literal>,
<literal>broadcast
</literal>,
<literal>anycast
</literal>,
1281 <literal>multicast
</literal>,
<literal>blackhole
</literal>,
<literal>unreachable
</literal>,
1282 <literal>prohibit
</literal>,
<literal>throw
</literal>,
<literal>nat
</literal>, and
1283 <literal>xresolve
</literal>. If
<literal>unicast
</literal>, a regular route is defined, i.e. a
1284 route indicating the path to take to a destination network address. If
<literal>blackhole
</literal>, packets
1285 to the defined route are discarded silently. If
<literal>unreachable
</literal>, packets to the defined route
1286 are discarded and the ICMP message
"Host Unreachable" is generated. If
<literal>prohibit
</literal>, packets
1287 to the defined route are discarded and the ICMP message
"Communication Administratively Prohibited" is
1288 generated. If
<literal>throw
</literal>, route lookup in the current routing table will fail and the route
1289 selection process will return to Routing Policy Database (RPDB). Defaults to
<literal>unicast
</literal>.
1294 <term><varname>InitialCongestionWindow=
</varname></term>
1296 <para>The TCP initial congestion window is used during the start of a TCP connection. During the start of a TCP
1297 session, when a client requests a resource, the server's initial congestion window determines how many data bytes
1298 will be sent during the initial burst of data. Takes a size in bytes between
1 and
4294967295 (
2^
32 -
1). The usual
1299 suffixes K, M, G are supported and are understood to the base of
1024. When unset, the kernel's default will be used.
1304 <term><varname>InitialAdvertisedReceiveWindow=
</varname></term>
1306 <para>The TCP initial advertised receive window is the amount of receive data (in bytes) that can initially be buffered at one time
1307 on a connection. The sending host can send only that amount of data before waiting for an acknowledgment and window update
1308 from the receiving host. Takes a size in bytes between
1 and
4294967295 (
2^
32 -
1). The usual suffixes K, M, G are supported
1309 and are understood to the base of
1024. When unset, the kernel's default will be used.
1314 <term><varname>QuickAck=
</varname></term>
1316 <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the kernel's default will be used.
1321 <term><varname>FastOpenNoCookie=
</varname></term>
1323 <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis.
1324 When unset, the kernel's default will be used.
1329 <term><varname>TTLPropagate=
</varname></term>
1331 <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress.
1332 When unset, the kernel's default will be used.
1337 <term><varname>MTUBytes=
</varname></term>
1339 <para>The maximum transmission unit in bytes to set for the
1340 route. The usual suffixes K, M, G, are supported and are
1341 understood to the base of
1024.
</para>
1342 <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
1343 below
1280 (the minimum MTU for IPv6) it will automatically be increased to this value.
</para>
1347 <term><varname>IPServiceType=
</varname></term>
1349 <para>Takes string;
<literal>CS6
</literal> or
<literal>CS4
</literal>. Used to set IP
1350 service type to CS6 (network control) or CS4 (Realtime). Defaults to CS6.
</para>
1354 <term><varname>MultiPathRoute=
<replaceable>address
</replaceable>[@
<replaceable>name
</replaceable>] [
<replaceable>weight
</replaceable>]
</varname></term>
1356 <para>Configures multipath route. Multipath routing is the technique of using multiple
1357 alternative paths through a network. Takes gateway address. Optionally, takes a network
1358 interface name or index separated with
<literal>@
</literal>, and a weight in
1.
.256 for
1359 this multipath route separated with whitespace. This setting can be specified multiple
1360 times. If an empty string is assigned, then the all previous assignments are cleared.
</para>
1367 <title>[DHCPv4] Section Options
</title>
1368 <para>The
<literal>[DHCPv4]
</literal> section configures the
1369 DHCPv4 client, if it is enabled with the
1370 <varname>DHCP=
</varname> setting described above:
</para>
1372 <variablelist class='network-directives'
>
1374 <term><varname>UseDNS=
</varname></term>
1376 <para>When true (the default), the DNS servers received
1377 from the DHCP server will be used and take precedence over
1378 any statically configured ones.
</para>
1380 <para>This corresponds to the
<option>nameserver
</option>
1381 option in
<citerefentry
1382 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1386 <term><varname>RoutesToDNS=
</varname></term>
1388 <para>When true, the routes to the DNS servers received from the DHCP server will be
1389 configured. When
<varname>UseDNS=
</varname> is disabled, this setting is ignored.
1390 Defaults to false.
</para>
1394 <term><varname>UseNTP=
</varname></term>
1396 <para>When true (the default), the NTP servers received
1397 from the DHCP server will be used by systemd-timesyncd
1398 and take precedence over any statically configured ones.
</para>
1402 <term><varname>UseSIP=
</varname></term>
1404 <para>When true (the default), the SIP servers received
1405 from the DHCP server will be saved at the state files and can be
1406 read via
<function>sd_network_link_get_sip_servers()
</function> function.
</para>
1411 <term><varname>UseMTU=
</varname></term>
1413 <para>When true, the interface maximum transmission unit
1414 from the DHCP server will be used on the current link.
1415 If
<varname>MTUBytes=
</varname> is set, then this setting is ignored.
1416 Defaults to false.
</para>
1420 <term><varname>Anonymize=
</varname></term>
1422 <para>Takes a boolean. When true, the options sent to the DHCP server will
1423 follow the
<ulink url=
"https://tools.ietf.org/html/rfc7844">RFC
7844</ulink>
1424 (Anonymity Profiles for DHCP Clients) to minimize disclosure of identifying information.
1425 Defaults to false.
</para>
1427 <para>This option should only be set to true when
1428 <varname>MACAddressPolicy=
</varname> is set to
<literal>random
</literal>
1430 project='man-pages'
><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
</para>
1432 <para>Note that this configuration will overwrite others.
1433 In concrete, the following variables will be ignored:
1434 <varname>SendHostname=
</varname>,
<varname>ClientIdentifier=
</varname>,
1435 <varname>UseRoutes=
</varname>,
<varname>UseMTU=
</varname>,
1436 <varname>VendorClassIdentifier=
</varname>,
<varname>UseTimezone=
</varname>.
</para>
1438 <para>With this option enabled DHCP requests will mimic those generated by Microsoft Windows, in
1439 order to reduce the ability to fingerprint and recognize installations. This means DHCP request
1440 sizes will grow and lease data will be more comprehensive than normally, though most of the
1441 requested data is not actually used.
</para>
1445 <term><varname>SendHostname=
</varname></term>
1447 <para>When true (the default), the machine's hostname will be sent to the DHCP server.
1448 Note that the machine's hostname must consist only of
7-bit ASCII lower-case characters and
1449 no spaces or dots, and be formatted as a valid DNS domain name. Otherwise, the hostname is not
1450 sent even if this is set to true.
</para>
1455 <term><varname>MUDURL=
</varname></term>
1457 <para>When configured, the Manufacturer Usage Descriptions (MUD) URL will be sent to the
1458 DHCPv4 server. Takes an URL of length up to
255 characters. A superficial verification that
1459 the string is a valid URL will be performed. DHCPv4 clients are intended to have at most one
1460 MUD URL associated with them. See
1461 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
</para>
1466 <term><varname>UseHostname=
</varname></term>
1468 <para>When true (the default), the hostname received from
1469 the DHCP server will be set as the transient hostname of the system.
1474 <term><varname>Hostname=
</varname></term>
1476 <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's hostname.
1477 Note that the specified hostname must consist only of
7-bit ASCII lower-case characters and
1478 no spaces or dots, and be formatted as a valid DNS domain name.
</para>
1482 <term><varname>UseDomains=
</varname></term>
1484 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
1485 received from the DHCP server will be used as DNS search domain over this link, similar to the effect of
1486 the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name received from
1487 the DHCP server will be used for routing DNS queries only, but not for searching, similar to the effect of
1488 the
<option>Domains=
</option> setting when the argument is prefixed with
<literal>~
</literal>. Defaults to
1491 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
1492 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
1493 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
1494 single-label names.
</para>
1496 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
1497 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1501 <term><varname>UseRoutes=
</varname></term>
1503 <para>When true (the default), the static routes will be requested from the DHCP server and added to the
1504 routing table with a metric of
1024, and a scope of
"global",
"link" or
"host", depending on the route's
1505 destination and gateway. If the destination is on the local host, e.g.,
127.x.x.x, or the same as the
1506 link's own address, the scope will be set to
"host". Otherwise if the gateway is null (a direct route), a
1507 "link" scope will be used. For anything else, scope defaults to
"global".
</para>
1511 <term><varname>UseGateway=
</varname></term>
1513 <para>When true, the gateway will be requested from the DHCP server and added to the routing table with a
1514 metric of
1024, and a scope of
"link". When unset, the value specified with
<option>UseRoutes=
</option>
1519 <term><varname>UseTimezone=
</varname></term>
1521 <listitem><para>When true, the timezone received from the
1522 DHCP server will be set as timezone of the local
1523 system. Defaults to
<literal>no
</literal>.
</para></listitem>
1527 <term><varname>ClientIdentifier=
</varname></term>
1529 <para>The DHCPv4 client identifier to use. Takes one of
<literal>mac
</literal>,
<literal>duid
</literal> or
<literal>duid-only
</literal>.
1530 If set to
<literal>mac
</literal>, the MAC address of the link is used.
1531 If set to
<literal>duid
</literal>, an RFC4361-compliant Client ID, which is the combination of IAID and DUID (see below), is used.
1532 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.
1533 Defaults to
<literal>duid
</literal>.
</para>
1538 <term><varname>VendorClassIdentifier=
</varname></term>
1540 <para>The vendor class identifier used to identify vendor
1541 type and configuration.
</para>
1546 <term><varname>UserClass=
</varname></term>
1548 <para>A DHCPv4 client can use UserClass option to identify the type or category of user or applications
1549 it represents. The information contained in this option is a string that represents the user class of which
1550 the client is a member. Each class sets an identifying string of information to be used by the DHCP
1551 service to classify clients. Takes a whitespace-separated list of strings.
</para>
1556 <term><varname>MaxAttempts=
</varname></term>
1558 <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a
1559 number or
<literal>infinity
</literal>. Defaults to
<literal>infinity
</literal>.
1560 Note that the time between retries is increased exponentially, so the network will not be
1561 overloaded even if this number is high.
</para>
1566 <term><varname>DUIDType=
</varname></term>
1568 <para>Override the global
<varname>DUIDType
</varname> setting for this network. See
1569 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1570 for a description of possible values.
</para>
1575 <term><varname>DUIDRawData=
</varname></term>
1577 <para>Override the global
<varname>DUIDRawData
</varname> setting for this network. See
1578 <citerefentry><refentrytitle>networkd.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1579 for a description of possible values.
</para>
1584 <term><varname>IAID=
</varname></term>
1586 <para>The DHCP Identity Association Identifier (IAID) for the interface, a
32-bit unsigned integer.
</para>
1591 <term><varname>RequestBroadcast=
</varname></term>
1593 <para>Request the server to use broadcast messages before
1594 the IP address has been configured. This is necessary for
1595 devices that cannot receive RAW packets, or that cannot
1596 receive packets at all before an IP address has been
1597 configured. On the other hand, this must not be enabled on
1598 networks where broadcasts are filtered out.
</para>
1603 <term><varname>RouteMetric=
</varname></term>
1605 <para>Set the routing metric for routes specified by the
1611 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1613 <para>The table identifier for DHCP routes (a number between
1 and
4294967295, or
0 to unset).
1614 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1616 <para>When used in combination with
<varname>VRF=
</varname> the
1617 VRF's routing table is used unless this parameter is specified.
1623 <term><varname>RouteMTUBytes=
</varname></term>
1625 <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further details.
</para>
1630 <term><varname>ListenPort=
</varname></term>
1632 <para>Allow setting custom port for the DHCP client to listen on.
</para>
1637 <term><varname>FallbackLeaseLifetimeSec=
</varname></term>
1639 <para>Allows to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease lifetime.
1640 Takes one of
<literal>forever
</literal> or
<literal>infinity
</literal> means that the address
1641 never expires. Defaults to unset.
</para>
1646 <term><varname>SendRelease=
</varname></term>
1648 <para>When true, the DHCPv4 client sends a DHCP release packet when it stops.
1649 Defaults to true.
</para>
1654 <term><varname>SendDecline=
</varname></term>
1656 <para>A boolean. When
<literal>true
</literal>, DHCPv4 clients receives IP address from DHCP server.
1657 After new IP is received, DHCPv4 performs IPv4 Duplicate Address Detection. If duplicate use of IP is detected
1658 the DHCPv4 client rejects the IP by sending a DHCPDECLINE packet DHCP clients try to obtain an IP address again.
1659 See
<ulink url=
"https://tools.ietf.org/html/rfc5227">RFC
5224</ulink>.
1660 Defaults to
<literal>unset
</literal>.
</para>
1665 <term><varname>BlackList=
</varname></term>
1667 <para>A whitespace-separated list of IPv4 addresses. DHCP offers from servers in the list are rejected.
</para>
1672 <term><varname>RequestOptions=
</varname></term>
1674 <para>When configured, allows to set arbitrary request options in the DHCPv4 request options list and will be
1675 sent to the DHCPV4 server. A whitespace-separated list of integers in the range
1.
.254. Defaults to unset.
</para>
1680 <term><varname>SendOption=
</varname></term>
1682 <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data type
1683 and data separated with a colon
1684 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1685 The option number must be an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
1686 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
1687 <literal>string
</literal>. Special characters in the data string may be escaped using
1688 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1689 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1690 then all options specified earlier are cleared. Defaults to unset.
</para>
1695 <term><varname>SendVendorOption=
</varname></term>
1697 <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data type
1698 and data separated with a colon
1699 (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
1700 The option number must be an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
1701 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
1702 <literal>string
</literal>. Special characters in the data string may be escaped using
1703 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1704 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1705 then all options specified earlier are cleared. Defaults to unset.
</para>
1712 <title>[DHCPv6] Section Options
</title>
1713 <para>The
<literal>[DHCPv6]
</literal> section configures the DHCPv6 client, if it is enabled with the
1714 <varname>DHCP=
</varname> setting described above, or invoked by the IPv6 Router Advertisement:
</para>
1716 <variablelist class='network-directives'
>
1718 <term><varname>UseDNS=
</varname></term>
1719 <term><varname>UseNTP=
</varname></term>
1721 <para>As in the
<literal>[DHCPv4]
</literal> section.
</para>
1726 <term><varname>RapidCommit=
</varname></term>
1728 <para>Takes a boolean. The DHCPv6 client can obtain configuration parameters from a DHCPv6 server through
1729 a rapid two-message exchange (solicit and reply). When the rapid commit option is enabled by both
1730 the DHCPv6 client and the DHCPv6 server, the two-message exchange is used, rather than the default
1731 four-method exchange (solicit, advertise, request, and reply). The two-message exchange provides
1732 faster client configuration and is beneficial in environments in which networks are under a heavy load.
1733 See
<ulink url=
"https://tools.ietf.org/html/rfc3315#section-17.2.1">RFC
3315</ulink> for details.
1734 Defaults to true.
</para>
1739 <term><varname>MUDURL=
</varname></term>
1741 <para>When configured, the Manufacturer Usage Descriptions (MUD) URL will be sent to the DHCPV6 server.
1742 Takes an URL of length up to
255 characters. A superficial verification that the string is a valid URL
1743 will be performed. DHCPv6 clients are intended to have at most one MUD URL associated with them. See
1744 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink>.
</para>
1749 <term><varname>RequestOptions=
</varname></term>
1751 <para>When configured, allows to set arbitrary request options in the DHCPv6 request options list and will
1752 sent to the DHCPV6 server. A whitespace-separated list of integers in the range
1.
.254. Defaults to unset.
</para>
1757 <term><varname>ForceDHCPv6PDOtherInformation=
</varname></term>
1759 <para>Takes a boolean that enforces DHCPv6 stateful mode when the 'Other information' bit is set in
1760 Router Advertisement messages. By default setting only the 'O' bit in Router Advertisements
1761 makes DHCPv6 request network information in a stateless manner using a two-message Information
1762 Request and Information Reply message exchange.
1763 <ulink url=
"https://tools.ietf.org/html/rfc7084">RFC
7084</ulink>, requirement WPD-
4, updates
1764 this behavior for a Customer Edge router so that stateful DHCPv6 Prefix Delegation is also
1765 requested when only the 'O' bit is set in Router Advertisements. This option enables such a CE
1766 behavior as it is impossible to automatically distinguish the intention of the 'O' bit otherwise.
1767 By default this option is set to 'false', enable it if no prefixes are delegated when the device
1768 should be acting as a CE router.
</para>
1773 <term><varname>PrefixDelegationHint=
</varname></term>
1775 <para>Takes an IPv6 address with prefix length as
<varname>Address=
</varname> in
1776 the
"[Network]" section. Specifies the DHCPv6 client for the requesting router to include
1777 a prefix-hint in the DHCPv6 solicitation. Prefix ranges
1.
.128. Defaults to unset.
</para>
1782 <term><varname>WithoutRA=
</varname></term>
1784 <para>When true, DHCPv6 client starts without router advertisements's managed or other address configuration flag.
1785 Defaults to false.
</para>
1790 <term><varname>SendOption=
</varname></term>
1792 <para>As in the
<literal>[DHCPv4]
</literal> section, however because DHCPv6 uses
16-bit fields to store
1793 option numbers, the option number is an integer in the range
1.
.65536.
</para>
1798 <term><varname>UserClass=
</varname></term>
1800 <para>A DHCPv6 client can use User Class option to identify the type or category of user or applications
1801 it represents. The information contained in this option is a string that represents the user class of which
1802 the client is a member. Each class sets an identifying string of information to be used by the DHCP
1803 service to classify clients. Special characters in the data string may be escaped using
1804 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
1805 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
1806 then all options specified earlier are cleared. Takes a whitespace-separated list of strings. Note that
1807 currently NUL bytes are not allowed.
</para>
1812 <term><varname>VendorClass=
</varname></term>
1814 <para>A DHCPv6 client can use VendorClass option to identify the vendor that
1815 manufactured the hardware on which the client is running. The information
1816 contained in the data area of this option is contained in one or more opaque
1817 fields that identify details of the hardware configuration. Takes a
1818 whitespace-separated list of strings.
</para>
1825 <title>[IPv6AcceptRA] Section Options
</title>
1826 <para>The
<literal>[IPv6AcceptRA]
</literal> section configures the IPv6 Router Advertisement
1827 (RA) client, if it is enabled with the
<varname>IPv6AcceptRA=
</varname> setting described
1830 <variablelist class='network-directives'
>
1832 <term><varname>UseDNS=
</varname></term>
1834 <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take
1835 precedence over any statically configured ones.
</para>
1837 <para>This corresponds to the
<option>nameserver
</option> option in
<citerefentry
1838 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1843 <term><varname>UseDomains=
</varname></term>
1845 <para>Takes a boolean, or the special value
<literal>route
</literal>. When true, the domain name
1846 received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
1847 the effect of the
<option>Domains=
</option> setting. If set to
<literal>route
</literal>, the domain name
1848 received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
1849 effect of the
<option>Domains=
</option> setting when the argument is prefixed with
1850 <literal>~
</literal>. Defaults to false.
</para>
1852 <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
1853 of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain
1854 only as routing domain, rather than as search domain, in order to not have it affect local resolution of
1855 single-label names.
</para>
1857 <para>When set to true, this setting corresponds to the
<option>domain
</option> option in
<citerefentry
1858 project='man-pages'
><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
1863 <term><varname>RouteTable=
<replaceable>num
</replaceable></varname></term>
1865 <para>The table identifier for the routes received in the Router Advertisement
1866 (a number between
1 and
4294967295, or
0 to unset).
1867 The table can be retrieved using
<command>ip route show table
<replaceable>num
</replaceable></command>.
1873 <term><varname>UseAutonomousPrefix=
</varname></term>
1875 <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take
1876 precedence over any statically configured ones.
</para>
1881 <term><varname>UseOnLinkPrefix=
</varname></term>
1883 <para>When true (the default), the onlink prefix received in the Router Advertisement will be used and take
1884 precedence over any statically configured ones.
</para>
1889 <term><varname>BlackList=
</varname></term>
1891 <para>A whitespace-separated list of IPv6 prefixes. IPv6 prefixes supplied via router advertisements in the list are ignored.
</para>
1896 <term><varname>DHCPv6Client=
</varname></term>
1898 <para>Takes a boolean, or the special value
<literal>always
</literal>. When true (the default), the DHCPv6 client will be started when the
1899 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
1900 managed or other information flag in the RA.
</para>
1907 <title>[DHCPServer] Section Options
</title>
1908 <para>The
<literal>[DHCPServer]
</literal> section contains
1909 settings for the DHCP server, if enabled via the
1910 <varname>DHCPServer=
</varname> option described above:
</para>
1912 <variablelist class='network-directives'
>
1915 <term><varname>PoolOffset=
</varname></term>
1916 <term><varname>PoolSize=
</varname></term>
1918 <listitem><para>Configures the pool of addresses to hand out. The pool
1919 is a contiguous sequence of IP addresses in the subnet configured for
1920 the server address, which does not include the subnet nor the broadcast
1921 address.
<varname>PoolOffset=
</varname> takes the offset of the pool
1922 from the start of subnet, or zero to use the default value.
1923 <varname>PoolSize=
</varname> takes the number of IP addresses in the
1924 pool or zero to use the default value. By default, the pool starts at
1925 the first address after the subnet address and takes up the rest of
1926 the subnet, excluding the broadcast address. If the pool includes
1927 the server address (the default), this is reserved and not handed
1928 out to clients.
</para></listitem>
1932 <term><varname>DefaultLeaseTimeSec=
</varname></term>
1933 <term><varname>MaxLeaseTimeSec=
</varname></term>
1935 <listitem><para>Control the default and maximum DHCP lease
1936 time to pass to clients. These settings take time values in seconds or
1937 another common time unit, depending on the suffix. The default
1938 lease time is used for clients that did not ask for a specific
1939 lease time. If a client asks for a lease time longer than the
1940 maximum lease time, it is automatically shortened to the
1941 specified time. The default lease time defaults to
1h, the
1942 maximum lease time to
12h. Shorter lease times are beneficial
1943 if the configuration data in DHCP leases changes frequently
1944 and clients shall learn the new settings with shorter
1945 latencies. Longer lease times reduce the generated DHCP
1946 network traffic.
</para></listitem>
1950 <term><varname>EmitDNS=
</varname></term>
1951 <term><varname>DNS=
</varname></term>
1953 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
1954 to clients shall contain DNS server information. Defaults to
<literal>yes
</literal>.
1955 The DNS servers to pass to clients may be configured with the
1956 <varname>DNS=
</varname> option, which takes a list of IPv4
1957 addresses. If the
<varname>EmitDNS=
</varname> option is
1958 enabled but no servers configured, the servers are
1959 automatically propagated from an
"uplink" interface that has
1960 appropriate servers set. The
"uplink" interface is determined
1961 by the default route of the system with the highest
1962 priority. Note that this information is acquired at the time
1963 the lease is handed out, and does not take uplink interfaces
1964 into account that acquire DNS or NTP server information at a
1965 later point. DNS server propagation does not take
1966 <filename>/etc/resolv.conf
</filename> into account. Also, note
1967 that the leases are not refreshed if the uplink network
1968 configuration changes. To ensure clients regularly acquire the
1969 most current uplink DNS server information, it is thus
1970 advisable to shorten the DHCP lease time via
1971 <varname>MaxLeaseTimeSec=
</varname> described
1972 above.
</para></listitem>
1976 <term><varname>EmitNTP=
</varname></term>
1977 <term><varname>NTP=
</varname></term>
1979 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
1980 <varname>DNS=
</varname> settings described above, these
1981 settings configure whether and what NTP server information
1982 shall be emitted as part of the DHCP lease. The same syntax,
1983 propagation semantics and defaults apply as for
1984 <varname>EmitDNS=
</varname> and
1985 <varname>DNS=
</varname>.
</para></listitem>
1989 <term><varname>EmitSIP=
</varname></term>
1990 <term><varname>SIP=
</varname></term>
1992 <listitem><para>Similar to the
<varname>EmitDNS=
</varname> and
1993 <varname>DNS=
</varname> settings described above, these
1994 settings configure whether and what SIP server information
1995 shall be emitted as part of the DHCP lease. The same syntax,
1996 propagation semantics and defaults apply as for
1997 <varname>EmitDNS=
</varname> and
1998 <varname>DNS=
</varname>.
</para></listitem>
2002 <term><varname>POP3Servers=
</varname></term>
2004 <listitem><para>Similar to the
<varname>DNS=
</varname> setting described above, this setting
2005 configures whether and what POP3 server information shall be emitted as part of the DHCP lease. The
2006 same syntax, propagation semantics and defaults apply as for
2007 <varname>DNS=
</varname>.
</para></listitem>
2011 <term><varname>SMTPServers=
</varname></term>
2013 <listitem><para>Similar to the
<varname>DNS=
</varname> setting described above, this
2014 setting configures whether and what SMTP server information shall be emitted as part of
2015 the DHCP lease. The same syntax, propagation semantics and defaults apply as for
2016 <varname>DNS=
</varname>.
</para></listitem>
2020 <term><varname>LPRServers=
</varname></term>
2022 <listitem><para>Similar to the
<varname>DNS=
</varname> setting described above, this
2023 setting configures whether and what LPR (line printer) server information shall be emitted
2024 as part of the DHCP lease. The same syntax, propagation semantics and defaults apply as for
2025 <varname>DNS=
</varname>.
</para></listitem>
2029 <term><varname>EmitRouter=
</varname></term>
2031 <listitem><para>Similar to the
<varname>EmitDNS=
</varname>
2032 setting described above, this setting configures whether the
2033 DHCP lease should contain the router option. The same syntax,
2034 propagation semantics and defaults apply as for
2035 <varname>EmitDNS=
</varname>.
</para></listitem>
2039 <term><varname>EmitTimezone=
</varname></term>
2040 <term><varname>Timezone=
</varname></term>
2042 <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out
2043 to clients shall contain timezone information. Defaults to
<literal>yes
</literal>. The
2044 <varname>Timezone=
</varname> setting takes a timezone string
2045 (such as
<literal>Europe/Berlin
</literal> or
2046 <literal>UTC
</literal>) to pass to clients. If no explicit
2047 timezone is set, the system timezone of the local host is
2048 propagated, as determined by the
2049 <filename>/etc/localtime
</filename> symlink.
</para></listitem>
2053 <term><varname>SendOption=
</varname></term>
2055 <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type
2056 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2057 The option number is an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
2058 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>,
<literal>ipv6address
</literal>, or
2059 <literal>string
</literal>. Special characters in the data string may be escaped using
2060 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2061 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2062 then all options specified earlier are cleared. Defaults to unset.
</para>
2067 <term><varname>SendVendorOption=
</varname></term>
2069 <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type
2070 and data (
<literal><replaceable>option
</replaceable>:
<replaceable>type
</replaceable>:
<replaceable>value
</replaceable></literal>).
2071 The option number is an integer in the range
1.
.254. The type takes one of
<literal>uint8
</literal>,
2072 <literal>uint16
</literal>,
<literal>uint32
</literal>,
<literal>ipv4address
</literal>, or
2073 <literal>string
</literal>. Special characters in the data string may be escaped using
2074 <ulink url=
"https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style
2075 escapes
</ulink>. This setting can be specified multiple times. If an empty string is specified,
2076 then all options specified earlier are cleared. Defaults to unset.
</para>
2084 <title>[IPv6PrefixDelegation] Section Options
</title>
2085 <para>The
<literal>[IPv6PrefixDelegation]
</literal> section contains
2086 settings for sending IPv6 Router Advertisements and whether to act as
2087 a router, if enabled via the
<varname>IPv6PrefixDelegation=
</varname>
2088 option described above. IPv6 network prefixes are defined with one or
2089 more
<literal>[IPv6Prefix]
</literal> sections.
</para>
2091 <variablelist class='network-directives'
>
2094 <term><varname>Managed=
</varname></term>
2095 <term><varname>OtherInformation=
</varname></term>
2097 <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6
2098 addresses on the network link when
<varname>Managed=
</varname>
2099 is set to
<literal>true
</literal> or if only additional network
2100 information can be obtained via DHCPv6 for the network link when
2101 <varname>OtherInformation=
</varname> is set to
2102 <literal>true
</literal>. Both settings default to
2103 <literal>false
</literal>, which means that a DHCPv6 server is not being
2104 used.
</para></listitem>
2108 <term><varname>RouterLifetimeSec=
</varname></term>
2110 <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. If set,
2111 this host also announces itself in Router Advertisements as an IPv6
2112 router for the network link. When unset, the host is not acting as a router.
</para>
2117 <term><varname>RouterPreference=
</varname></term>
2119 <listitem><para>Configures IPv6 router preference if
2120 <varname>RouterLifetimeSec=
</varname> is non-zero. Valid values are
2121 <literal>high
</literal>,
<literal>medium
</literal> and
2122 <literal>low
</literal>, with
<literal>normal
</literal> and
2123 <literal>default
</literal> added as synonyms for
2124 <literal>medium
</literal> just to make configuration easier. See
2125 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2126 for details. Defaults to
<literal>medium
</literal>.
</para></listitem>
2130 <term><varname>EmitDNS=
</varname></term>
2131 <term><varname>DNS=
</varname></term>
2133 <listitem><para><varname>DNS=
</varname> specifies a list of recursive DNS server IPv6 addresses
2134 that are distributed via Router Advertisement messages when
<varname>EmitDNS=
</varname> is
2135 true.
<varname>DNS=
</varname> also takes special value
<literal>_link_local
</literal>; in that
2136 case the IPv6 link local address is distributed. If
<varname>DNS=
</varname> is empty, DNS
2137 servers are read from the
<literal>[Network]
</literal> section. If the
2138 <literal>[Network]
</literal> section does not contain any DNS servers either, DNS servers from
2139 the uplink with the highest priority default route are used. When
<varname>EmitDNS=
</varname>
2140 is false, no DNS server information is sent in Router Advertisement messages.
2141 <varname>EmitDNS=
</varname> defaults to true.
2146 <term><varname>EmitDomains=
</varname></term>
2147 <term><varname>Domains=
</varname></term>
2149 <listitem><para>A list of DNS search domains distributed via Router
2150 Advertisement messages when
<varname>EmitDomains=
</varname> is true. If
2151 <varname>Domains=
</varname> is empty, DNS search domains are read from the
2152 <literal>[Network]
</literal> section. If the
<literal>[Network]
</literal>
2153 section does not contain any DNS search domains either, DNS search
2154 domains from the uplink with the highest priority default route are
2155 used. When
<varname>EmitDomains=
</varname> is false, no DNS search domain
2156 information is sent in Router Advertisement messages.
2157 <varname>EmitDomains=
</varname> defaults to true.
2162 <term><varname>DNSLifetimeSec=
</varname></term>
2164 <listitem><para>Lifetime in seconds for the DNS server addresses listed
2165 in
<varname>DNS=
</varname> and search domains listed in
2166 <varname>Domains=
</varname>.
</para></listitem>
2173 <title>[IPv6Prefix] Section Options
</title>
2174 <para>One or more
<literal>[IPv6Prefix]
</literal> sections contain the IPv6
2175 prefixes that are announced via Router Advertisements. See
2176 <ulink url=
"https://tools.ietf.org/html/rfc4861">RFC
4861</ulink>
2177 for further details.
</para>
2179 <variablelist class='network-directives'
>
2182 <term><varname>AddressAutoconfiguration=
</varname></term>
2183 <term><varname>OnLink=
</varname></term>
2185 <listitem><para>Takes a boolean to specify whether IPv6 addresses can be
2186 autoconfigured with this prefix and whether the prefix can be used for
2187 onlink determination. Both settings default to
<literal>true
</literal>
2188 in order to ease configuration.
2193 <term><varname>Prefix=
</varname></term>
2195 <listitem><para>The IPv6 prefix that is to be distributed to hosts.
2196 Similarly to configuring static IPv6 addresses, the setting is
2197 configured as an IPv6 prefix and its prefix length, separated by a
2198 <literal>/
</literal> character. Use multiple
2199 <literal>[IPv6Prefix]
</literal> sections to configure multiple IPv6
2200 prefixes since prefix lifetimes, address autoconfiguration and onlink
2201 status may differ from one prefix to another.
</para></listitem>
2205 <term><varname>PreferredLifetimeSec=
</varname></term>
2206 <term><varname>ValidLifetimeSec=
</varname></term>
2208 <listitem><para>Preferred and valid lifetimes for the prefix measured in
2209 seconds.
<varname>PreferredLifetimeSec=
</varname> defaults to
604800
2210 seconds (one week) and
<varname>ValidLifetimeSec=
</varname> defaults
2211 to
2592000 seconds (
30 days).
</para></listitem>
2215 <term><varname>Assign=
</varname></term>
2216 <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
2223 <title>[IPv6RoutePrefix] Section Options
</title>
2224 <para>One or more
<literal>[IPv6RoutePrefix]
</literal> sections contain the IPv6
2225 prefix routes that are announced via Router Advertisements. See
2226 <ulink url=
"https://tools.ietf.org/html/rfc4191">RFC
4191</ulink>
2227 for further details.
</para>
2229 <variablelist class='network-directives'
>
2232 <term><varname>Route=
</varname></term>
2234 <listitem><para>The IPv6 route that is to be distributed to hosts.
2235 Similarly to configuring static IPv6 routes, the setting is
2236 configured as an IPv6 prefix routes and its prefix route length,
2237 separated by a
<literal>/
</literal> character. Use multiple
2238 <literal>[IPv6PrefixRoutes]
</literal> sections to configure multiple IPv6
2239 prefix routes.
</para></listitem>
2243 <term><varname>LifetimeSec=
</varname></term>
2245 <listitem><para>Lifetime for the route prefix measured in
2246 seconds.
<varname>LifetimeSec=
</varname> defaults to
604800 seconds (one week).
2254 <title>[Bridge] Section Options
</title>
2255 <para>The
<literal>[Bridge]
</literal> section accepts the
2256 following keys.
</para>
2257 <variablelist class='network-directives'
>
2259 <term><varname>UnicastFlood=
</varname></term>
2261 <para>Takes a boolean. Controls whether the bridge should flood
2262 traffic for which an FDB entry is missing and the destination
2263 is unknown through this port. When unset, the kernel's default will be used.
2268 <term><varname>MulticastFlood=
</varname></term>
2270 <para>Takes a boolean. Controls whether the bridge should flood
2271 traffic for which an MDB entry is missing and the destination
2272 is unknown through this port. When unset, the kernel's default will be used.
2277 <term><varname>MulticastToUnicast=
</varname></term>
2279 <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of
2280 the bridge. Which means unicast copies are only delivered to hosts which are interested in it.
2281 When unset, the kernel's default will be used.
2286 <term><varname>NeighborSuppression=
</varname></term>
2288 <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for
2289 this port. When unset, the kernel's default will be used.
2294 <term><varname>Learning=
</varname></term>
2296 <para>Takes a boolean. Configures whether MAC address learning is enabled for
2297 this port. When unset, the kernel's default will be used.
2302 <term><varname>HairPin=
</varname></term>
2304 <para>Takes a boolean. Configures whether traffic may be sent back
2305 out of the port on which it was received. When this flag is false, and the bridge
2306 will not forward traffic back out of the receiving port.
2307 When unset, the kernel's default will be used.
</para>
2311 <term><varname>UseBPDU=
</varname></term>
2313 <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be
2314 processed by the bridge port. When unset, the kernel's default will be used.
</para>
2318 <term><varname>FastLeave=
</varname></term>
2320 <para>Takes a boolean. This flag allows the bridge to immediately stop multicast
2321 traffic on a port that receives an IGMP Leave message. It is only used with
2322 IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.
</para>
2326 <term><varname>AllowPortToBeRoot=
</varname></term>
2328 <para>Takes a boolean. Configures whether a given port is allowed to
2329 become a root port. Only used when STP is enabled on the bridge.
2330 When unset, the kernel's default will be used.
</para>
2334 <term><varname>ProxyARP=
</varname></term>
2336 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port.
2337 When unset, the kernel's default will be used.
</para>
2341 <term><varname>ProxyARPWiFi=
</varname></term>
2343 <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port
2344 which meets extended requirements by IEEE
802.11 and Hotspot
2.0 specifications.
2345 When unset, the kernel's default will be used.
</para>
2349 <term><varname>MulticastRouter=
</varname></term>
2351 <para>Configures this port for having multicast routers attached. A port with a multicast
2352 router will receive all multicast traffic. Takes one of
<literal>no
</literal>
2353 to disable multicast routers on this port,
<literal>query
</literal> to let the system detect
2354 the presence of routers,
<literal>permanent
</literal> to permanently enable multicast traffic
2355 forwarding on this port, or
<literal>temporary
</literal> to enable multicast routers temporarily
2356 on this port, not depending on incoming queries. When unset, the kernel's default will be used.
</para>
2360 <term><varname>Cost=
</varname></term>
2362 <para>Sets the
"cost" of sending packets of this interface.
2363 Each port in a bridge may have a different speed and the cost
2364 is used to decide which link to use. Faster interfaces
2365 should have lower costs. It is an integer value between
1 and
2370 <term><varname>Priority=
</varname></term>
2372 <para>Sets the
"priority" of sending packets on this interface.
2373 Each port in a bridge may have a different priority which is used
2374 to decide which link to use. Lower value means higher priority.
2375 It is an integer value between
0 to
63. Networkd does not set any
2376 default, meaning the kernel default value of
32 is used.
</para>
2382 <title>[BridgeFDB] Section Options
</title>
2383 <para>The
<literal>[BridgeFDB]
</literal> section manages the
2384 forwarding database table of a port and accepts the following
2385 keys. Specify several
<literal>[BridgeFDB]
</literal> sections to
2386 configure several static MAC table entries.
</para>
2388 <variablelist class='network-directives'
>
2390 <term><varname>MACAddress=
</varname></term>
2392 <para>As in the
<literal>[Network]
</literal> section. This
2393 key is mandatory.
</para>
2397 <term><varname>Destination=
</varname></term>
2399 <para>Takes an IP address of the destination VXLAN tunnel endpoint.
</para>
2403 <term><varname>VLANId=
</varname></term>
2405 <para>The VLAN ID for the new static MAC table entry. If
2406 omitted, no VLAN ID information is appended to the new static MAC
2411 <term><varname>VNI=
</varname></term>
2413 <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to
2414 the remote VXLAN tunnel endpoint. Takes a number in the range
1-
16777215.
2415 Defaults to unset.
</para>
2419 <term><varname>AssociatedWith=
</varname></term>
2421 <para>Specifies where the address is associated with. Takes one of
<literal>use
</literal>,
2422 <literal>self
</literal>,
<literal>master
</literal> or
<literal>router
</literal>.
2423 <literal>use
</literal> means the address is in use. User space can use this option to
2424 indicate to the kernel that the fdb entry is in use.
<literal>self
</literal> means
2425 the address is associated with the port drivers fdb. Usually hardware.
<literal>master
</literal>
2426 means the address is associated with master devices fdb.
<literal>router
</literal> means
2427 the destination address is associated with a router. Note that it's valid if the referenced
2428 device is a VXLAN type device and has route shortcircuit enabled. Defaults to
<literal>self
</literal>.
</para>
2435 <title>[LLDP] Section Options
</title>
2436 <para>The
<literal>[LLDP]
</literal> section manages the Link Layer Discovery Protocol (LLDP) and accepts the
2437 following keys.
</para>
2438 <variablelist class='network-directives'
>
2440 <term><varname>MUDURL=
</varname></term>
2442 <para>Controls support for Ethernet LLDP packet's Manufacturer Usage Description (MUD). MUD is an embedded software
2443 standard defined by the IETF that allows IoT Device makers to advertise device specifications, including the intended
2444 communication patterns for their device when it connects to the network. The network can then use this intent to author
2445 a context-specific access policy, so the device functions only within those parameters. Takes an URL of length up to
255
2446 characters. A superficial verification that the string is a valid URL
2447 will be performed. See
2448 <ulink url=
"https://tools.ietf.org/html/rfc8520">RFC
8520</ulink> for details. The MUD URL received
2449 from the LLDP packets will be saved at the state files and can be read via
2450 <function>sd_lldp_neighbor_get_mud_url()
</function> function.
</para>
2457 <title>[CAN] Section Options
</title>
2458 <para>The
<literal>[CAN]
</literal> section manages the Controller Area Network (CAN bus) and accepts the
2459 following keys.
</para>
2460 <variablelist class='network-directives'
>
2462 <term><varname>BitRate=
</varname></term>
2464 <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of
1000 can
2465 be used here. Takes a number in the range
1.
.4294967295.
</para>
2469 <term><varname>SamplePoint=
</varname></term>
2471 <para>Optional sample point in percent with one decimal (e.g.
<literal>75%
</literal>,
2472 <literal>87.5%
</literal>) or permille (e.g.
<literal>875‰
</literal>).
</para>
2476 <term><varname>DataBitRate=
</varname></term>
2477 <term><varname>DataSamplePoint=
</varname></term>
2479 <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are
2480 analogous to the
<varname>BitRate=
</varname> and
<varname>SamplePoint=
</varname> keys.
</para>
2484 <term><varname>FDMode=
</varname></term>
2486 <para>Takes a boolean. When
<literal>yes
</literal>, CAN-FD mode is enabled for the interface.
2487 Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using
2488 the
<varname>DataBitRate=
</varname> and
<varname>DataSamplePoint=
</varname> keys.
</para>
2492 <term><varname>FDNonISO=
</varname></term>
2494 <para>Takes a boolean. When
<literal>yes
</literal>, non-ISO CAN-FD mode is enabled for the
2495 interface. When unset, the kernel's default will be used.
</para>
2499 <term><varname>RestartSec=
</varname></term>
2501 <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be
2502 triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can
2503 be specified using decimals (e.g.
<literal>0.1s
</literal>) or a
<literal>ms
</literal> or
2504 <literal>us
</literal> postfix. Using
<literal>infinity
</literal> or
<literal>0</literal> will turn the
2505 automatic restart off. By default automatic restart is disabled.
</para>
2509 <term><varname>Termination=
</varname></term>
2511 <para>Takes a boolean. When
<literal>yes
</literal>, the termination resistor will be selected for
2512 the bias network. When unset, the kernel's default will be used.
</para>
2516 <term><varname>TripleSampling=
</varname></term>
2518 <para>Takes a boolean. When
<literal>yes
</literal>, three samples (instead of one) are used to determine
2519 the value of a received bit by majority rule. When unset, the kernel's default will be used.
</para>
2523 <term><varname>ListenOnly=
</varname></term>
2525 <para>Takes a boolean. When
<literal>yes
</literal>, listen-only mode is enabled. When the
2526 interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK
2527 bit. Listen-only mode is important to debug CAN networks without interfering with the
2528 communication or acknowledge the CAN frame. When unset, the kernel's default will be used.
2536 <title>[QDisc] Section Options
</title>
2537 <para>The
<literal>[QDisc]
</literal> section manages the traffic control queueing discipline (qdisc).
</para>
2539 <variablelist class='network-directives'
>
2541 <term><varname>Parent=
</varname></term>
2543 <para>Specifies the parent Queueing Discipline (qdisc). Takes one of
<literal>clsact
</literal>
2544 or
<literal>ingress
</literal>. This is mandatory.
</para>
2548 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2553 <title>[NetworkEmulator] Section Options
</title>
2554 <para>The
<literal>[NetworkEmulator]
</literal> section manages the queueing discipline (qdisc) of
2555 the network emulator. It can be used to configure the kernel packet scheduler and simulate packet
2556 delay and loss for UDP or TCP applications, or limit the bandwidth usage of a particular service to
2557 simulate internet connections.
</para>
2559 <variablelist class='network-directives'
>
2560 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2561 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2564 <term><varname>DelaySec=
</varname></term>
2566 <para>Specifies the fixed amount of delay to be added to all packets going out of the
2567 interface. Defaults to unset.
</para>
2572 <term><varname>DelayJitterSec=
</varname></term>
2574 <para>Specifies the chosen delay to be added to the packets outgoing to the network
2575 interface. Defaults to unset.
</para>
2580 <term><varname>PacketLimit=
</varname></term>
2582 <para>Specifies the maximum number of packets the qdisc may hold queued at a time.
2583 An unsigned integer ranges
0 to
4294967294. Defaults to
1000.
</para>
2588 <term><varname>LossRate=
</varname></term>
2590 <para>Specifies an independent loss probability to be added to the packets outgoing from the
2591 network interface. Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
2596 <term><varname>DuplicateRate=
</varname></term>
2598 <para>Specifies that the chosen percent of packets is duplicated before queuing them.
2599 Takes a percentage value, suffixed with
"%". Defaults to unset.
</para>
2606 <title>[TokenBucketFilter] Section Options
</title>
2607 <para>The
<literal>[TokenBucketFilter]
</literal> section manages the queueing discipline (qdisc) of
2608 token bucket filter (tbf).
</para>
2610 <variablelist class='network-directives'
>
2611 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2612 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2615 <term><varname>LatencySec=
</varname></term>
2617 <para>Specifies the latency parameter, which specifies the maximum amount of time a
2618 packet can sit in the Token Bucket Filter (TBF). Defaults to unset.
</para>
2623 <term><varname>LimitSize=
</varname></term>
2625 <para>Takes the number of bytes that can be queued waiting for tokens to become available.
2626 When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes,
2627 respectively, to the base of
1000. Defaults to unset.
</para>
2632 <term><varname>Burst=
</varname></term>
2634 <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens
2635 can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is
2636 parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1000. Defaults to
2642 <term><varname>Rate=
</varname></term>
2644 <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified
2645 bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000.
2646 Defaults to unset.
</para>
2651 <term><varname>MPUBytes=
</varname></term>
2653 <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes)
2654 for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
2655 Megabytes, or Gigabytes, respectively, to the base of
1000. Defaults to zero.
</para>
2660 <term><varname>PeakRate=
</varname></term>
2662 <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the
2663 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
2664 1000. Defaults to unset.
</para>
2669 <term><varname>MTUBytes=
</varname></term>
2671 <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified
2672 size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1000.
2673 Defaults to unset.
</para>
2680 <title>[PIE] Section Options
</title>
2681 <para>The
<literal>[PIE]
</literal> section manages the queueing discipline
2682 (qdisc) of Proportional Integral controller-Enhanced (PIE).
</para>
2684 <variablelist class='network-directives'
>
2685 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2686 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2689 <term><varname>PacketLimit=
</varname></term>
2691 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
2692 dropped. An unsigned integer ranges
1 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2699 <title>[StochasticFairBlue] Section Options
</title>
2700 <para>The
<literal>[StochasticFairBlue]
</literal> section manages the queueing discipline
2701 (qdisc) of stochastic fair blue (sfb).
</para>
2703 <variablelist class='network-directives'
>
2704 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2705 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2708 <term><varname>PacketLimit=
</varname></term>
2710 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
2711 dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2718 <title>[StochasticFairnessQueueing] Section Options
</title>
2719 <para>The
<literal>[StochasticFairnessQueueing]
</literal> section manages the queueing discipline
2720 (qdisc) of stochastic fairness queueing (sfq).
</para>
2722 <variablelist class='network-directives'
>
2723 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2724 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2727 <term><varname>PerturbPeriodSec=
</varname></term>
2729 <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.
</para>
2736 <title>[BFIFO] Section Options
</title>
2737 <para>The
<literal>[BFIFO]
</literal> section manages the queueing discipline (qdisc) of
2738 Byte limited Packet First In First Out (bfifo).
</para>
2740 <variablelist class='network-directives'
>
2741 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2742 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2745 <term><varname>LimitSize=
</varname></term>
2747 <para>Specifies the hard limit on the FIFO size in bytes. The size limit (a buffer size) to prevent it
2748 from overflowing in case it is unable to dequeue packets as quickly as it receives them. When this limit
2749 is reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed as
2750 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
2757 <title>[PFIFO] Section Options
</title>
2758 <para>The
<literal>[PFIFO]
</literal> section manages the queueing discipline (qdisc) of
2759 Packet First In First Out (pfifo).
</para>
2761 <variablelist class='network-directives'
>
2762 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2763 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2766 <term><varname>PacketLimit=
</varname></term>
2768 <para>Specifies the hard limit on the FIFO size in number of packets. The size limit (a buffer size) to prevent it
2769 from overflowing in case it is unable to dequeue packets as quickly as it receives them. When this limit is reached,
2770 incoming packets are dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2777 <title>[PFIFOHeadDrop] Section Options
</title>
2778 <para>The
<literal>[PFIFOHeadDrop]
</literal> section manages the queueing discipline (qdisc) of
2779 Packet First In First Out Head Drop (pfifo_head_drop).
</para>
2781 <variablelist class='network-directives'
>
2782 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2783 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2786 <term><varname>PacketLimit=
</varname></term>
2788 <para>As in
<literal>[PFIFO]
</literal> section.
</para></listitem>
2794 <title>[PFIFOFast] Section Options
</title>
2795 <para>The
<literal>[PFIFOFast]
</literal> section manages the queueing discipline (qdisc) of
2796 Packet First In First Out Fast (pfifo_fast).
</para>
2798 <variablelist class='network-directives'
>
2799 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2800 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2805 <title>[CAKE] Section Options
</title>
2806 <para>The
<literal>[CAKE]
</literal> section manages the queueing discipline (qdisc) of
2807 Common Applications Kept Enhanced (CAKE).
</para>
2809 <variablelist class='network-directives'
>
2810 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2811 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2814 <term><varname>Overhead=
</varname></term>
2816 <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative.
2817 Takes an integer ranges -
64 to
256. Defaults to unset and kernel's default is used.
</para>
2822 <term><varname>Bandwidth=
</varname></term>
2824 <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is
2825 parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
1000. Defaults to
2826 unset and kernel's default is used.
</para>
2833 <title>[ControlledDelay] Section Options
</title>
2834 <para>The
<literal>[ControlledDelay]
</literal> section manages the queueing discipline (qdisc) of
2835 controlled delay (CoDel).
</para>
2837 <variablelist class='network-directives'
>
2838 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2839 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2842 <term><varname>PacketLimit=
</varname></term>
2844 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
2845 dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
2850 <term><varname>TargetSec=
</varname></term>
2852 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
2853 Defaults to unset and kernel's default is used.
</para>
2858 <term><varname>IntervalSec=
</varname></term>
2860 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
2861 become too stale. Defaults to unset and kernel's default is used.
</para>
2866 <term><varname>ECN=
</varname></term>
2868 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
2869 unset and kernel's default is used.
</para>
2874 <term><varname>CEThresholdSec=
</varname></term>
2876 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
2877 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
2884 <title>[DeficitRoundRobinScheduler] Section Options
</title>
2885 <para>The
<literal>[DeficitRoundRobinScheduler]
</literal> section manages the queueing discipline (qdisc) of
2886 Deficit Round Robin Scheduler (DRR).
</para>
2888 <variablelist class='network-directives'
>
2889 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2890 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2895 <title>[DeficitRoundRobinSchedulerClass] Section Options
</title>
2896 <para>The
<literal>[DeficitRoundRobinSchedulerClass]
</literal> section manages the traffic control class of
2897 Deficit Round Robin Scheduler (DRR).
</para>
2899 <variablelist class='network-directives'
>
2900 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
2901 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
2904 <term><varname>Quantum=
</varname></term>
2906 <para>Specifies the amount of bytes a flow is allowed to dequeue before the
2907 scheduler moves to the next class. An unsigned integer ranges
1 to
4294967294.
2908 Defaults to the MTU of the interface.
</para>
2916 <title>[GenericRandomEarlyDetection] Section Options
</title>
2917 <para>The
<literal>[GenericRandomEarlyDetection]
</literal> section manages the queueing discipline
2918 (qdisc) of Generic Random Early Detection (GRED).
</para>
2920 <variablelist class='network-directives'
>
2921 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2922 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2925 <term><varname>VirtualQueues=
</varname></term>
2927 <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>
2932 <term><varname>DefaultVirtualQueue=
</varname></term>
2934 <para>Specifies the number of default virtual queue. This must be less than
<varname>VirtualQueue=
</varname>.
2935 Defaults to unset and kernel's default is used.
</para>
2940 <term><varname>GenericRIO=
</varname></term>
2942 <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to
2943 unset and kernel's default is used.
</para>
2950 <title>[FairQueueingControlledDelay] Section Options
</title>
2951 <para>The
<literal>[FairQueueingControlledDelay]
</literal> section manages the queueing discipline
2952 (qdisc) of fair queuing controlled delay (FQ-CoDel).
</para>
2954 <variablelist class='network-directives'
>
2955 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
2956 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
2959 <term><varname>PacketLimit=
</varname></term>
2961 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
2962 dropped. Defaults to unset and kernel's default is used.
</para>
2967 <term><varname>MemoryLimit=
</varname></term>
2969 <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance.
2970 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
2971 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
2976 <term><varname>Flows=
</varname></term>
2978 <para>Specifies the number of flows into which the incoming packets are classified.
2979 Defaults to unset and kernel's default is used.
</para>
2984 <term><varname>TargetSec=
</varname></term>
2986 <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay.
2987 Defaults to unset and kernel's default is used.
</para>
2992 <term><varname>IntervalSec=
</varname></term>
2994 <para>Takes a timespan. This is used to ensure that the measured minimum delay does not
2995 become too stale. Defaults to unset and kernel's default is used.
</para>
3000 <term><varname>Quantum=
</varname></term>
3002 <para>Specifies the number of bytes used as 'deficit' in the fair queuing algorithmtimespan.
3003 When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes,
3004 respectively, to the base of
1024. Defaults to unset and kernel's default is used.
</para>
3009 <term><varname>ECN=
</varname></term>
3011 <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to
3012 unset and kernel's default is used.
</para>
3017 <term><varname>CEThresholdSec=
</varname></term>
3019 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3020 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3027 <title>[FairQueueing] Section Options
</title>
3028 <para>The
<literal>[FairQueueing]
</literal> section manages the queueing discipline
3029 (qdisc) of fair queue traffic policing (FQ).
</para>
3031 <variablelist class='network-directives'
>
3032 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3033 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3036 <term><varname>PacketLimit=
</varname></term>
3038 <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are
3039 dropped. Defaults to unset and kernel's default is used.
</para>
3044 <term><varname>FlowLimit=
</varname></term>
3046 <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to
3047 unset and kernel's default is used.
</para>
3052 <term><varname>Quantum=
</varname></term>
3054 <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed
3055 to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes,
3056 Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and kernel's
3057 default is used.
</para>
3062 <term><varname>InitialQuantum=
</varname></term>
3064 <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is
3065 allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as
3066 Kilobytes, Megabytes, or Gigabytes, respectively, to the base of
1024. Defaults to unset and
3067 kernel's default is used.
</para>
3072 <term><varname>MaximumRate=
</varname></term>
3074 <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the
3075 specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of
3076 1000. Defaults to unset and kernel's default is used.
</para>
3081 <term><varname>Buckets=
</varname></term>
3083 <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and
3084 kernel's default is used.
</para>
3089 <term><varname>OrphanMask=
</varname></term>
3091 <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part
3092 of hash and reduce number of buckets associated with the traffic. Defaults to unset and
3093 kernel's default is used.
</para>
3098 <term><varname>Pacing=
</varname></term>
3100 <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's
3101 default is used.
</para>
3106 <term><varname>CEThresholdSec=
</varname></term>
3108 <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN
3109 Congestion Experienced (CE). Defaults to unset and kernel's default is used.
</para>
3116 <title>[TrivialLinkEqualizer] Section Options
</title>
3117 <para>The
<literal>[TrivialLinkEqualizer]
</literal> section manages the queueing discipline (qdisc) of
3118 trivial link equalizer (teql).
</para>
3120 <variablelist class='network-directives'
>
3121 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3122 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3125 <term><varname>Id=
</varname></term>
3127 <para>Specifies the interface ID
<literal>N
</literal> of teql. Defaults to
<literal>0</literal>.
3128 Note that when teql is used, currently, the module
<constant>sch_teql
</constant> with
3129 <constant>max_equalizers=N+
1</constant> option must be loaded before
3130 <command>systemd-networkd
</command> is started.
</para>
3137 <title>[HierarchyTokenBucket] Section Options
</title>
3138 <para>The
<literal>[HierarchyTokenBucket]
</literal> section manages the queueing discipline (qdisc) of
3139 hierarchy token bucket (htb).
</para>
3141 <variablelist class='network-directives'
>
3142 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3143 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3146 <term><varname>DefaultClass=
</varname></term>
3148 <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent
3149 to the class. Defaults to unset.
</para>
3156 <title>[HierarchyTokenBucketClass] Section Options
</title>
3157 <para>The
<literal>[HierarchyTokenBucketClass]
</literal> section manages the traffic control class of
3158 hierarchy token bucket (htb).
</para>
3160 <variablelist class='network-directives'
>
3161 <xi:include href=
"tc.xml" xpointer=
"tclass-parent" />
3162 <xi:include href=
"tc.xml" xpointer=
"tclass-classid" />
3165 <term><varname>Priority=
</varname></term>
3167 <para>Specifies the priority of the class. In the round-robin process, classes with the lowest
3168 priority field are tried for packets first. This setting is mandatory.
</para>
3173 <term><varname>Rate=
</varname></term>
3175 <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed
3176 with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively,
3177 to the base of
1000. This setting is mandatory.
</para>
3182 <term><varname>CeilRate=
</varname></term>
3184 <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare.
3185 When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits,
3186 respectively, to the base of
1000. When unset, the value specified with
<varname>Rate=
</varname>
3194 <title>[HeavyHitterFilter] Section Options
</title>
3195 <para>The
<literal>[HeavyHitterFilter]
</literal> section manages the queueing discipline
3196 (qdisc) of Heavy Hitter Filter (hhf).
</para>
3198 <variablelist class='network-directives'
>
3199 <xi:include href=
"tc.xml" xpointer=
"qdisc-parent" />
3200 <xi:include href=
"tc.xml" xpointer=
"qdisc-handle" />
3203 <term><varname>PacketLimit=
</varname></term>
3205 <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, incoming packets are
3206 dropped. An unsigned integer ranges
0 to
4294967294. Defaults to unset and kernel's default is used.
</para>
3213 <title>[BridgeVLAN] Section Options
</title>
3214 <para>The
<literal>[BridgeVLAN]
</literal> section manages the VLAN ID configuration of a bridge port and accepts
3215 the following keys. Specify several
<literal>[BridgeVLAN]
</literal> sections to configure several VLAN entries.
3216 The
<varname>VLANFiltering=
</varname> option has to be enabled, see
<literal>[Bridge]
</literal> section in
3217 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
3219 <variablelist class='network-directives'
>
3221 <term><varname>VLAN=
</varname></term>
3223 <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. VLAN IDs are valid
3224 from
1 to
4094.
</para>
3228 <term><varname>EgressUntagged=
</varname></term>
3230 <para>The VLAN ID specified here will be used to untag frames on egress. Configuring
3231 <varname>EgressUntagged=
</varname> implicates the use of
<varname>VLAN=
</varname> above and will enable the
3232 VLAN ID for ingress as well. This can be either a single ID or a range M-N.
</para>
3236 <term><varname>PVID=
</varname></term>
3238 <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress.
3239 <varname>PVID=
</varname> can be used only once. Configuring
<varname>PVID=
</varname> implicates the use of
3240 <varname>VLAN=
</varname> above and will enable the VLAN ID for ingress as well.
</para>
3247 <title>Examples
</title>
3249 <title>Static network configuration
</title>
3251 <programlisting># /etc/systemd/network/
50-static.network
3256 Address=
192.168.0.15/
24
3257 Gateway=
192.168.0.1</programlisting>
3259 <para>This brings interface
<literal>enp2s0
</literal> up with a static address. The
3260 specified gateway will be used for a default route.
</para>
3264 <title>DHCP on ethernet links
</title>
3266 <programlisting># /etc/systemd/network/
80-dhcp.network
3271 DHCP=yes
</programlisting>
3273 <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with
3274 <literal>en
</literal> (i.e. ethernet interfaces).
</para>
3278 <title>IPv6 Prefix Delegation
</title>
3280 <programlisting># /etc/systemd/network/
55-ipv6-pd-upstream.network
3285 DHCP=ipv6
</programlisting>
3287 <programlisting># /etc/systemd/network/
56-ipv6-pd-downstream.network
3292 IPv6PrefixDelegation=dhcpv6
</programlisting>
3294 <para>This will enable IPv6 PD on the interface enp1s0 as an upstream interface where the
3295 DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to.
</para>
3299 <title>A bridge with two enslaved links
</title>
3301 <programlisting># /etc/systemd/network/
25-bridge-static.network
3306 Address=
192.168.0.15/
24
3308 DNS=
192.168.0.1</programlisting>
3310 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
1.network
3315 Bridge=bridge0
</programlisting>
3317 <programlisting># /etc/systemd/network/
25-bridge-slave-interface-
2.network
3322 Bridge=bridge0
</programlisting>
3324 <para>This creates a bridge and attaches devices
<literal>enp2s0
</literal> and
3325 <literal>wlp3s0
</literal> to it. The bridge will have the specified static address
3326 and network assigned, and a default route via the specified gateway will be
3327 added. The specified DNS server will be added to the global list of DNS resolvers.
3335 # /etc/systemd/network/
20-bridge-slave-interface-vlan.network
3351 EgressUntagged=
300-
400</programlisting>
3353 <para>This overrides the configuration specified in the previous example for the
3354 interface
<literal>enp2s0
</literal>, and enables VLAN on that bridge port. VLAN IDs
3355 1-
32,
42,
100-
400 will be allowed. Packets tagged with VLAN IDs
42,
300-
400 will be
3356 untagged when they leave on this interface. Untagged packets which arrive on this
3357 interface will be assigned VLAN ID
42.
</para>
3361 <title>Various tunnels
</title>
3363 <programlisting>/etc/systemd/network/
25-tunnels.network
3374 <programlisting>/etc/systemd/network/
25-tunnel-ipip.netdev
3380 <programlisting>/etc/systemd/network/
25-tunnel-sit.netdev
3386 <programlisting>/etc/systemd/network/
25-tunnel-gre.netdev
3392 <programlisting>/etc/systemd/network/
25-tunnel-vti.netdev
3398 <para>This will bring interface
<literal>ens1
</literal> up and create an IPIP tunnel,
3399 a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.
</para>
3403 <title>A bond device
</title>
3405 <programlisting># /etc/systemd/network/
30-bond1.network
3413 <programlisting># /etc/systemd/network/
30-bond1.netdev
3419 <programlisting># /etc/systemd/network/
30-bond1-dev1.network
3421 MACAddress=
52:
54:
00:e9:
64:
41
3427 <programlisting># /etc/systemd/network/
30-bond1-dev2.network
3429 MACAddress=
52:
54:
00:e9:
64:
42
3435 <para>This will create a bond device
<literal>bond1
</literal> and enslave the two
3436 devices with MAC addresses
52:
54:
00:e9:
64:
41 and
52:
54:
00:e9:
64:
42 to it. IPv6 DHCP
3437 will be used to acquire an address.
</para>
3441 <title>Virtual Routing and Forwarding (VRF)
</title>
3442 <para>Add the
<literal>bond1
</literal> interface to the VRF master interface
3443 <literal>vrf1
</literal>. This will redirect routes generated on this interface to be
3444 within the routing table defined during VRF creation. For kernels before
4.8 traffic
3445 won't be redirected towards the VRFs routing table unless specific ip-rules are added.
3447 <programlisting># /etc/systemd/network/
25-vrf.network
3457 <title>MacVTap
</title>
3458 <para>This brings up a network interface
<literal>macvtap-test
</literal>
3459 and attaches it to
<literal>enp0s25
</literal>.
</para>
3460 <programlisting># /usr/lib/systemd/network/
25-macvtap.network
3465 MACVTAP=macvtap-test
3470 <title>A Xfrm interface with physical underlying device.
</title>
3472 <programlisting># /etc/systemd/network/
27-xfrm.netdev
3477 InterfaceId=
7</programlisting>
3479 <programlisting># /etc/systemd/network/
27-eth0.network
3484 Xfrm=xfrm0
</programlisting>
3486 <para>This creates a
<literal>xfrm0
</literal> interface and binds it to the
<literal>eth0
</literal> device.
3487 This allows hardware based ipsec offloading to the
<literal>eth0
</literal> nic.
3488 If offloading is not needed, xfrm interfaces can be assigned to the
<literal>lo
</literal> device.
3494 <title>See Also
</title>
3496 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
3497 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
3498 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
3499 <citerefentry><refentrytitle>systemd.netdev
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
3500 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
projects / thirdparty / systemd.git / blob