1 <?xml version='
1.0'
?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
6 SPDX-License-Identifier: LGPL-2.1+
8 This file is part of systemd.
10 Copyright 2013 Tom Gundersen
12 systemd is free software; you can redistribute it and/or modify it
13 under the terms of the GNU Lesser General Public License as published by
14 the Free Software Foundation; either version 2.1 of the License, or
15 (at your option) any later version.
17 systemd is distributed in the hope that it will be useful, but
18 WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 Lesser General Public License for more details.
22 You should have received a copy of the GNU Lesser General Public License
23 along with systemd; If not, see <http://www.gnu.org/licenses/>.
26 <refentry id=
"systemd.netdev" conditional='ENABLE_NETWORKD'
>
29 <title>systemd.network
</title>
30 <productname>systemd
</productname>
34 <contrib>Developer
</contrib>
35 <firstname>Tom
</firstname>
36 <surname>Gundersen
</surname>
37 <email>teg@jklm.no
</email>
43 <refentrytitle>systemd.netdev
</refentrytitle>
44 <manvolnum>5</manvolnum>
48 <refname>systemd.netdev
</refname>
49 <refpurpose>Virtual Network Device configuration
</refpurpose>
53 <para><filename><replaceable>netdev
</replaceable>.netdev
</filename></para>
57 <title>Description
</title>
59 <para>Network setup is performed by
60 <citerefentry><refentrytitle>systemd-networkd
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
63 <para>The main Virtual Network Device file must have the extension
<filename>.netdev
</filename>;
64 other extensions are ignored. Virtual network devices are created as soon as networkd is
65 started. If a netdev with the specified name already exists, networkd will use that as-is rather
66 than create its own. Note that the settings of the pre-existing netdev will not be changed by
69 <para>The
<filename>.netdev
</filename> files are read from the files located in the system
70 network directory
<filename>/usr/lib/systemd/network
</filename>, the volatile runtime network
71 directory
<filename>/run/systemd/network
</filename> and the local administration network
72 directory
<filename>/etc/systemd/network
</filename>. All configuration files are collectively
73 sorted and processed in lexical order, regardless of the directories in which they live.
74 However, files with identical filenames replace each other. Files in
<filename>/etc
</filename>
75 have the highest priority, files in
<filename>/run
</filename> take precedence over files with
76 the same name in
<filename>/usr/lib
</filename>. This can be used to override a system-supplied
77 configuration file with a local file if needed. As a special case, an empty file (file size
0)
78 or symlink with the same name pointing to
<filename>/dev/null
</filename> disables the
79 configuration file entirely (it is
"masked").
</para>
81 <para>Along with the netdev file
<filename>foo.netdev
</filename>, a
"drop-in" directory
82 <filename>foo.netdev.d/
</filename> may exist. All files with the suffix
<literal>.conf
</literal>
83 from this directory will be parsed after the file itself is parsed. This is useful to alter or
84 add configuration settings, without having to modify the main configuration file. Each drop-in
85 file must have appropriate section headers.
</para>
87 <para>In addition to
<filename>/etc/systemd/network
</filename>, drop-in
<literal>.d
</literal>
88 directories can be placed in
<filename>/usr/lib/systemd/network
</filename> or
89 <filename>/run/systemd/network
</filename> directories. Drop-in files in
90 <filename>/etc
</filename> take precedence over those in
<filename>/run
</filename> which in turn
91 take precedence over those in
<filename>/usr/lib
</filename>. Drop-in files under any of these
92 directories take precedence over the main netdev file wherever located. (Of course, since
93 <filename>/run
</filename> is temporary and
<filename>/usr/lib
</filename> is for vendors, it is
94 unlikely drop-ins should be used in either of those places.)
</para>
98 <title>Supported netdev kinds
</title>
100 <para>The following kinds of virtual network devices may be
101 configured in
<filename>.netdev
</filename> files:
</para>
104 <title>Supported kinds of virtual network devices
</title>
107 <colspec colname='kind'
/>
108 <colspec colname='explanation'
/>
111 <entry>Description
</entry>
114 <row><entry><varname>bond
</varname></entry>
115 <entry>A bond device is an aggregation of all its slave devices. See
<ulink url=
"https://www.kernel.org/doc/Documentation/networking/bonding.txt">Linux Ethernet Bonding Driver HOWTO
</ulink> for details.Local configuration
</entry></row>
117 <row><entry><varname>bridge
</varname></entry>
118 <entry>A bridge device is a software switch, and each of its slave devices and the bridge itself are ports of the switch.
</entry></row>
120 <row><entry><varname>dummy
</varname></entry>
121 <entry>A dummy device drops all packets sent to it.
</entry></row>
123 <row><entry><varname>gre
</varname></entry>
124 <entry>A Level
3 GRE tunnel over IPv4. See
<ulink url=
"https://tools.ietf.org/html/rfc2784">RFC
2784</ulink> for details.
</entry></row>
126 <row><entry><varname>gretap
</varname></entry>
127 <entry>A Level
2 GRE tunnel over IPv4.
</entry></row>
129 <row><entry><varname>ip6gre
</varname></entry>
130 <entry>A Level
3 GRE tunnel over IPv6.
</entry></row>
132 <row><entry><varname>ip6tnl
</varname></entry>
133 <entry>An IPv4 or IPv6 tunnel over IPv6
</entry></row>
135 <row><entry><varname>ip6gretap
</varname></entry>
136 <entry>A Level
2 GRE tunnel over IPv6.
</entry></row>
138 <row><entry><varname>ipip
</varname></entry>
139 <entry>An IPv4 over IPv4 tunnel.
</entry></row>
141 <row><entry><varname>ipvlan
</varname></entry>
142 <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.
</entry></row>
144 <row><entry><varname>macvlan
</varname></entry>
145 <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.
</entry></row>
147 <row><entry><varname>macvtap
</varname></entry>
148 <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.
</entry></row>
150 <row><entry><varname>sit
</varname></entry>
151 <entry>An IPv6 over IPv4 tunnel.
</entry></row>
153 <row><entry><varname>tap
</varname></entry>
154 <entry>A persistent Level
2 tunnel between a network device and a device node.
</entry></row>
156 <row><entry><varname>tun
</varname></entry>
157 <entry>A persistent Level
3 tunnel between a network device and a device node.
</entry></row>
159 <row><entry><varname>veth
</varname></entry>
160 <entry>An Ethernet tunnel between a pair of network devices.
</entry></row>
162 <row><entry><varname>vlan
</varname></entry>
163 <entry>A VLAN is a stacked device which receives packets from its underlying device based on VLAN tagging. See
<ulink url=
"http://www.ieee802.org/1/pages/802.1Q.html">IEEE
802.1Q
</ulink> for details.
</entry></row>
165 <row><entry><varname>vti
</varname></entry>
166 <entry>An IPv4 over IPSec tunnel.
</entry></row>
168 <row><entry><varname>vti6
</varname></entry>
169 <entry>An IPv6 over IPSec tunnel.
</entry></row>
171 <row><entry><varname>vxlan
</varname></entry>
172 <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.
</entry></row>
174 <row><entry><varname>geneve
</varname></entry>
175 <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.
</entry></row>
177 <row><entry><varname>vrf
</varname></entry>
178 <entry>A Virtual Routing and Forwarding (
<ulink url=
"https://www.kernel.org/doc/Documentation/networking/vrf.txt">VRF
</ulink>) interface to create separate routing and forwarding domains.
</entry></row>
180 <row><entry><varname>vcan
</varname></entry>
181 <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.
</entry></row>
183 <row><entry><varname>vxcan
</varname></entry>
184 <entry>The virtual CAN tunnel driver (vxcan). Similar to the virtual ethernet driver veth, vxcan implements a local CAN traffic tunnel between two virtual CAN network devices. When creating a vxcan, two vxcan devices are created as pair. When one end receives the packet it appears on its pair and vice versa. The vxcan can be used for cross namespace communication.
187 <row><entry><varname>wireguard
</varname></entry>
188 <entry>WireGuard Secure Network Tunnel.
</entry></row>
197 <title>[Match] Section Options
</title>
199 <para>A virtual network device is only created if the
200 <literal>[Match]
</literal> section matches the current
201 environment, or if the section is empty. The following keys are
204 <variablelist class='network-directives'
>
206 <term><varname>Host=
</varname></term>
208 <para>Matches against the hostname or machine ID of the
209 host. See
<literal>ConditionHost=
</literal> in
210 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
216 <term><varname>Virtualization=
</varname></term>
218 <para>Checks whether the system is executed in a virtualized
219 environment and optionally test whether it is a specific
221 <literal>ConditionVirtualization=
</literal> in
222 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
228 <term><varname>KernelCommandLine=
</varname></term>
230 <para>Checks whether a specific kernel command line option
231 is set (or if prefixed with the exclamation mark unset). See
232 <literal>ConditionKernelCommandLine=
</literal> in
233 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
239 <term><varname>KernelVersion=
</varname></term>
241 <para>Checks whether the kernel version (as reported by
<command>uname -r
</command>) matches a certain
242 expression (or if prefixed with the exclamation mark does not match it). See
243 <literal>ConditionKernelVersion=
</literal> in
244 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
249 <term><varname>Architecture=
</varname></term>
251 <para>Checks whether the system is running on a specific
252 architecture. See
<literal>ConditionArchitecture=
</literal> in
253 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
263 <title>[NetDev] Section Options
</title>
265 <para>The
<literal>[NetDev]
</literal> section accepts the
266 following keys:
</para>
268 <variablelist class='network-directives'
>
270 <term><varname>Description=
</varname></term>
272 <para>A free-form description of the netdev.
</para>
276 <term><varname>Name=
</varname></term>
278 <para>The interface name used when creating the netdev.
279 This option is compulsory.
</para>
283 <term><varname>Kind=
</varname></term>
285 <para>The netdev kind. This option is compulsory. See the
286 <literal>Supported netdev kinds
</literal> section for the
291 <term><varname>MTUBytes=
</varname></term>
293 <para>The maximum transmission unit in bytes to set for
294 the device. The usual suffixes K, M, G, are supported and
295 are understood to the base of
1024. This key is not
296 currently supported for
<literal>tun
</literal> or
297 <literal>tap
</literal> devices.
302 <term><varname>MACAddress=
</varname></term>
304 <para>The MAC address to use for the device. If none is
305 given, one is generated based on the interface name and
307 <citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
308 This key is not currently supported for
309 <literal>tun
</literal> or
<literal>tap
</literal> devices.
317 <title>[Bridge] Section Options
</title>
319 <para>The
<literal>[Bridge]
</literal> section only applies for
320 netdevs of kind
<literal>bridge
</literal>, and accepts the
321 following keys:
</para>
323 <variablelist class='network-directives'
>
325 <term><varname>HelloTimeSec=
</varname></term>
327 <para>HelloTimeSec specifies the number of seconds between two hello packets
328 sent out by the root bridge and the designated bridges. Hello packets are
329 used to communicate information about the topology throughout the entire
330 bridged local area network.
</para>
334 <term><varname>MaxAgeSec=
</varname></term>
336 <para>MaxAgeSec specifies the number of seconds of maximum message age.
337 If the last seen (received) hello packet is more than this number of
338 seconds old, the bridge in question will start the takeover procedure
339 in attempt to become the Root Bridge itself.
</para>
343 <term><varname>ForwardDelaySec=
</varname></term>
345 <para>ForwardDelaySec specifies the number of seconds spent in each
346 of the Listening and Learning states before the Forwarding state is entered.
</para>
350 <term><varname>AgeingTimeSec=
</varname></term>
352 <para>This specifies the number of seconds a MAC Address will be kept in
353 the forwarding database after having a packet received from this MAC Address.
</para>
357 <term><varname>Priority=
</varname></term>
359 <para>The priority of the bridge. An integer between
0 and
65535. A lower value
360 means higher priority. The bridge having the lowest priority will be elected as root bridge.
</para>
364 <term><varname>GroupForwardMask=
</varname></term>
366 <para>A
16-bit bitmask represented as an integer which allows forwarding of link
367 local frames with
802.1D reserved addresses (
01:
80:C2:
00:
00:
0X). A logical AND
368 is performed between the specified bitmask and the exponentiation of
2^X, the
369 lower nibble of the last octet of the MAC address. For example, a value of
8
370 would allow forwarding of frames addressed to
01:
80:C2:
00:
00:
03 (
802.1X PAE).
</para>
374 <term><varname>DefaultPVID=
</varname></term>
376 <para>This specifies the default port VLAN ID of a newly attached bridge port.
377 Set this to an integer in the range
1–
4094 or
<literal>none
</literal> to disable the PVID.
</para>
381 <term><varname>MulticastQuerier=
</varname></term>
383 <para>A boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
384 If enabled, the kernel will send general ICMP queries from a zero source address.
385 This feature should allow faster convergence on startup, but it causes some
386 multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
387 When unset, the kernel's default setting applies.
392 <term><varname>MulticastSnooping=
</varname></term>
394 <para>A boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
395 If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
396 between hosts and multicast routers. When unset, the kernel's default setting applies.
401 <term><varname>VLANFiltering=
</varname></term>
403 <para>A boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
404 If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's
405 default setting applies.
410 <term><varname>STP=
</varname></term>
412 <para>A boolean. This enables the bridge's Spanning Tree Protocol (STP). When unset,
413 the kernel's default setting applies.
421 <title>[VLAN] Section Options
</title>
423 <para>The
<literal>[VLAN]
</literal> section only applies for
424 netdevs of kind
<literal>vlan
</literal>, and accepts the
425 following key:
</para>
427 <variablelist class='network-directives'
>
429 <term><varname>Id=
</varname></term>
431 <para>The VLAN ID to use. An integer in the range
0–
4094.
432 This option is compulsory.
</para>
436 <term><varname>GVRP=
</varname></term>
438 <para>The Generic VLAN Registration Protocol (GVRP) is a protocol that
439 allows automatic learning of VLANs on a network. A boolean. When unset,
440 the kernel's default setting applies.
</para>
444 <term><varname>MVRP=
</varname></term>
446 <para>Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
447 Registration Protocol (GVRP) is a standards-based Layer
2 network protocol,
448 for automatic configuration of VLAN information on switches. It was defined
449 in the
802.1ak amendment to
802.1Q-
2005. A boolean. When unset, the kernel's
450 default setting applies.
</para>
454 <term><varname>LooseBinding=
</varname></term>
456 <para>The VLAN loose binding mode, in which only the operational state is passed
457 from the parent to the associated VLANs, but the VLAN device state is not changed.
458 A boolean. When unset, the kernel's default setting applies.
</para>
462 <term><varname>ReorderHeader=
</varname></term>
464 <para>The VLAN reorder header is set VLAN interfaces behave like physical interfaces.
465 A boolean. When unset, the kernel's default setting applies.
</para>
472 <title>[MACVLAN] Section Options
</title>
474 <para>The
<literal>[MACVLAN]
</literal> section only applies for
475 netdevs of kind
<literal>macvlan
</literal>, and accepts the
476 following key:
</para>
478 <variablelist class='network-directives'
>
480 <term><varname>Mode=
</varname></term>
482 <para>The MACVLAN mode to use. The supported options are
483 <literal>private
</literal>,
484 <literal>vepa
</literal>,
485 <literal>bridge
</literal>, and
486 <literal>passthru
</literal>.
495 <title>[MACVTAP] Section Options
</title>
497 <para>The
<literal>[MACVTAP]
</literal> section applies for
498 netdevs of kind
<literal>macvtap
</literal> and accepts the
499 same key as
<literal>[MACVLAN]
</literal>.
</para>
504 <title>[IPVLAN] Section Options
</title>
506 <para>The
<literal>[IPVLAN]
</literal> section only applies for
507 netdevs of kind
<literal>ipvlan
</literal>, and accepts the
508 following key:
</para>
510 <variablelist class='network-directives'
>
512 <term><varname>Mode=
</varname></term>
514 <para>The IPVLAN mode to use. The supported options are
515 <literal>L2
</literal>,
<literal>L3
</literal> and
<literal>L3S
</literal>.
520 <term><varname>Flags=
</varname></term>
522 <para>The IPVLAN flags to use. The supported options are
523 <literal>bridge
</literal>,
<literal>private
</literal> and
<literal>vepa
</literal>.
532 <title>[VXLAN] Section Options
</title>
533 <para>The
<literal>[VXLAN]
</literal> section only applies for
534 netdevs of kind
<literal>vxlan
</literal>, and accepts the
535 following keys:
</para>
537 <variablelist class='network-directives'
>
539 <term><varname>Id=
</varname></term>
541 <para>The VXLAN ID to use.
</para>
545 <term><varname>Remote=
</varname></term>
547 <para>Configures destination IP address.
</para>
551 <term><varname>Local=
</varname></term>
553 <para>Configures local IP address.
</para>
557 <term><varname>TOS=
</varname></term>
559 <para>The Type Of Service byte value for a vxlan interface.
</para>
563 <term><varname>TTL=
</varname></term>
565 <para>A fixed Time To Live N on Virtual eXtensible Local
566 Area Network packets. N is a number in the range
1–
255.
0
567 is a special value meaning that packets inherit the TTL
572 <term><varname>MacLearning=
</varname></term>
574 <para>A boolean. When true, enables dynamic MAC learning
575 to discover remote MAC addresses.
</para>
579 <term><varname>FDBAgeingSec=
</varname></term>
581 <para>The lifetime of Forwarding Database entry learnt by
582 the kernel, in seconds.
</para>
586 <term><varname>MaximumFDBEntries=
</varname></term>
588 <para>Configures maximum number of FDB entries.
</para>
592 <term><varname>ReduceARPProxy=
</varname></term>
594 <para>A boolean. When true, bridge-connected VXLAN tunnel
595 endpoint answers ARP requests from the local bridge on behalf
596 of remote Distributed Overlay Virtual Ethernet
597 <ulink url=
"https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
598 (DVOE)
</ulink> clients. Defaults to false.
</para>
602 <term><varname>L2MissNotification=
</varname></term>
604 <para>A boolean. When true, enables netlink LLADDR miss
605 notifications.
</para>
609 <term><varname>L3MissNotification=
</varname></term>
611 <para>A boolean. When true, enables netlink IP address miss
612 notifications.
</para>
616 <term><varname>RouteShortCircuit=
</varname></term>
618 <para>A boolean. When true, route short circuiting is turned
623 <term><varname>UDPChecksum=
</varname></term>
625 <para>A boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.
</para>
629 <term><varname>UDP6ZeroChecksumTx=
</varname></term>
631 <para>A boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.
</para>
635 <term><varname>UDP6ZeroChecksumRx=
</varname></term>
637 <para>A boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.
</para>
641 <term><varname>RemoteChecksumTx=
</varname></term>
643 <para>A boolean. When true, remote transmit checksum offload of VXLAN is turned on.
</para>
647 <term><varname>RemoteChecksumRx=
</varname></term>
649 <para>A boolean. When true, remote receive checksum offload in VXLAN is turned on.
</para>
653 <term><varname>GroupPolicyExtension=
</varname></term>
655 <para>A boolean. When true, it enables Group Policy VXLAN extension security label mechanism
656 across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
657 <ulink url=
"https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
658 VXLAN Group Policy
</ulink> document. Defaults to false.
</para>
662 <term><varname>DestinationPort=
</varname></term>
664 <para>Configures the default destination UDP port on a per-device basis.
665 If destination port is not specified then Linux kernel default will be used.
666 Set destination port
4789 to get the IANA assigned value. If not set or if the
667 destination port is assigned the empty string the default port of
4789 is used.
</para>
671 <term><varname>PortRange=
</varname></term>
673 <para>Configures VXLAN port range. VXLAN bases source
674 UDP port based on flow to help the receiver to be able
675 to load balance based on outer header flow. It
676 restricts the port range to the normal UDP local
677 ports, and allows overriding via configuration.
</para>
681 <term><varname>FlowLabel=
</varname></term>
683 <para>Specifies the flow label to use in outgoing packets.
684 The valid range is
0-
1048575.
691 <title>[GENEVE] Section Options
</title>
692 <para>The
<literal>[GENEVE]
</literal> section only applies for
693 netdevs of kind
<literal>geneve
</literal>, and accepts the
694 following keys:
</para>
696 <variablelist class='network-directives'
>
698 <term><varname>Id=
</varname></term>
700 <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [
0-
16777215].
</para>
704 <term><varname>Remote=
</varname></term>
706 <para>Specifies the unicast destination IP address to use in outgoing packets.
</para>
710 <term><varname>TOS=
</varname></term>
712 <para>Specifies the TOS value to use in outgoing packets. Ranges [
1-
255].
</para>
716 <term><varname>TTL=
</varname></term>
718 <para>Specifies the TTL value to use in outgoing packets. Ranges [
1-
255].
</para>
722 <term><varname>UDPChecksum=
</varname></term>
724 <para>A boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.
</para>
728 <term><varname>UDP6ZeroChecksumTx=
</varname></term>
730 <para>A boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.
</para>
734 <term><varname>UDP6ZeroChecksumRx=
</varname></term>
736 <para>A boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.
</para>
740 <term><varname>DestinationPort=
</varname></term>
742 <para>Specifies destination port. Defaults to
6081. If not set or assigned the empty string, the default
743 port of
6081 is used.
</para>
747 <term><varname>FlowLabel=
</varname></term>
749 <para>Specifies the flow label to use in outgoing packets.
</para>
755 <title>[Tunnel] Section Options
</title>
757 <para>The
<literal>[Tunnel]
</literal> section only applies for
759 <literal>ipip
</literal>,
760 <literal>sit
</literal>,
761 <literal>gre
</literal>,
762 <literal>gretap
</literal>,
763 <literal>ip6gre
</literal>,
764 <literal>ip6gretap
</literal>,
765 <literal>vti
</literal>,
766 <literal>vti6
</literal>, and
767 <literal>ip6tnl
</literal> and accepts
768 the following keys:
</para>
770 <variablelist class='network-directives'
>
772 <term><varname>Local=
</varname></term>
774 <para>A static local address for tunneled packets. It must
775 be an address on another interface of this host.
</para>
779 <term><varname>Remote=
</varname></term>
781 <para>The remote endpoint of the tunnel.
</para>
785 <term><varname>TOS=
</varname></term>
787 <para>The Type Of Service byte value for a tunnel interface.
788 For details about the TOS, see the
789 <ulink url=
"http://tools.ietf.org/html/rfc1349"> Type of
790 Service in the Internet Protocol Suite
</ulink> document.
795 <term><varname>TTL=
</varname></term>
797 <para>A fixed Time To Live N on tunneled packets. N is a
798 number in the range
1–
255.
0 is a special value meaning that
799 packets inherit the TTL value. The default value for IPv4
800 tunnels is: inherit. The default value for IPv6 tunnels is
805 <term><varname>DiscoverPathMTU=
</varname></term>
807 <para>A boolean. When true, enables Path MTU Discovery on
812 <term><varname>IPv6FlowLabel=
</varname></term>
814 <para>Configures the
20-bit flow label (see
<ulink url=
"https://tools.ietf.org/html/rfc6437">
815 RFC
6437</ulink>) field in the IPv6 header (see
<ulink url=
"https://tools.ietf.org/html/rfc2460">
816 RFC
2460</ulink>), which is used by a node to label packets of a flow.
817 It is only used for IPv6 tunnels.
818 A flow label of zero is used to indicate packets that have
820 It can be configured to a value in the range
0–
0xFFFFF, or be
821 set to
<literal>inherit
</literal>, in which case the original flowlabel is used.
</para>
825 <term><varname>CopyDSCP=
</varname></term>
827 <para>A boolean. When true, the Differentiated Service Code
828 Point (DSCP) field will be copied to the inner header from
829 outer header during the decapsulation of an IPv6 tunnel
830 packet. DSCP is a field in an IP packet that enables different
831 levels of service to be assigned to network traffic.
832 Defaults to
<literal>no
</literal>.
837 <term><varname>EncapsulationLimit=
</varname></term>
839 <para>The Tunnel Encapsulation Limit option specifies how many additional
840 levels of encapsulation are permitted to be prepended to the packet.
841 For example, a Tunnel Encapsulation Limit option containing a limit
842 value of zero means that a packet carrying that option may not enter
843 another tunnel before exiting the current tunnel.
844 (see
<ulink url=
"https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC
2473</ulink>).
845 The valid range is
0–
255 and
<literal>none
</literal>. Defaults to
4.
850 <term><varname>Key=
</varname></term>
852 <para>The
<varname>Key=
</varname> parameter specifies the same key to use in
853 both directions (
<varname>InputKey=
</varname> and
<varname>OutputKey=
</varname>).
854 The
<varname>Key=
</varname> is either a number or an IPv4 address-like dotted quad.
855 It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
856 and control path) in ip xfrm (framework used to implement IPsec protocol).
857 See
<ulink url=
"http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
858 ip-xfrm — transform configuration
</ulink> for details. It is only used for VTI/VTI6
863 <term><varname>InputKey=
</varname></term>
865 <para>The
<varname>InputKey=
</varname> parameter specifies the key to use for input.
866 The format is same as
<varname>Key=
</varname>. It is only used for VTI/VTI6 tunnels.
</para>
870 <term><varname>OutputKey=
</varname></term>
872 <para>The
<varname>OutputKey=
</varname> parameter specifies the key to use for output.
873 The format is same as
<varname>Key=
</varname>. It is only used for VTI/VTI6 tunnels.
</para>
877 <term><varname>Mode=
</varname></term>
879 <para>An
<literal>ip6tnl
</literal> tunnel can be in one of three
881 <literal>ip6ip6
</literal> for IPv6 over IPv6,
882 <literal>ipip6
</literal> for IPv4 over IPv6 or
883 <literal>any
</literal> for either.
888 <term><varname>Independent=
</varname></term>
890 <para>A boolean. When true tunnel does not require .network file. Created as
"tunnel@NONE".
891 Defaults to
<literal>false
</literal>.
896 <term><varname>AllowLocalRemote=
</varname></term>
898 <para>A boolean. When true allows tunnel traffic on
<varname>ip6tnl
</varname> devices where the remote endpoint is a local host address.
906 <title>[Peer] Section Options
</title>
908 <para>The
<literal>[Peer]
</literal> section only applies for
909 netdevs of kind
<literal>veth
</literal> and accepts the
910 following keys:
</para>
912 <variablelist class='network-directives'
>
914 <term><varname>Name=
</varname></term>
916 <para>The interface name used when creating the netdev.
917 This option is compulsory.
</para>
921 <term><varname>MACAddress=
</varname></term>
923 <para>The peer MACAddress, if not set, it is generated in
924 the same way as the MAC address of the main
931 <title>[VXCAN] Section Options
</title>
932 <para>The
<literal>[VXCAN]
</literal> section only applies for
933 netdevs of kind
<literal>vxcan
</literal> and accepts the
934 following key:
</para>
936 <variablelist class='network-directives'
>
938 <term><varname>Peer=
</varname></term>
940 <para>The peer interface name used when creating the netdev.
941 This option is compulsory.
</para>
947 <title>[Tun] Section Options
</title>
949 <para>The
<literal>[Tun]
</literal> section only applies for
950 netdevs of kind
<literal>tun
</literal>, and accepts the following
953 <variablelist class='network-directives'
>
955 <term><varname>OneQueue=
</varname></term>
956 <listitem><para>Takes a boolean argument. Configures whether
957 all packets are queued at the device (enabled), or a fixed
958 number of packets are queued at the device and the rest at the
959 <literal>qdisc
</literal>. Defaults to
960 <literal>no
</literal>.
</para>
964 <term><varname>MultiQueue=
</varname></term>
965 <listitem><para>Takes a boolean argument. Configures whether
966 to use multiple file descriptors (queues) to parallelize
967 packets sending and receiving. Defaults to
968 <literal>no
</literal>.
</para>
972 <term><varname>PacketInfo=
</varname></term>
973 <listitem><para>Takes a boolean argument. Configures whether
974 packets should be prepended with four extra bytes (two flag
975 bytes and two protocol bytes). If disabled, it indicates that
976 the packets will be pure IP packets. Defaults to
977 <literal>no
</literal>.
</para>
981 <term><varname>VNetHeader=
</varname></term>
982 <listitem><para>Takes a boolean argument. Configures
983 IFF_VNET_HDR flag for a tap device. It allows sending
984 and receiving larger Generic Segmentation Offload (GSO)
985 packets. This may increase throughput significantly.
987 <literal>no
</literal>.
</para>
991 <term><varname>User=
</varname></term>
992 <listitem><para>User to grant access to the
993 <filename>/dev/net/tun
</filename> device.
</para>
997 <term><varname>Group=
</varname></term>
998 <listitem><para>Group to grant access to the
999 <filename>/dev/net/tun
</filename> device.
</para>
1008 <title>[Tap] Section Options
</title>
1010 <para>The
<literal>[Tap]
</literal> section only applies for
1011 netdevs of kind
<literal>tap
</literal>, and accepts the same keys
1012 as the
<literal>[Tun]
</literal> section.
</para>
1016 <title>[WireGuard] Section Options
</title>
1018 <para>The
<literal>[WireGuard]
</literal> section accepts the following
1021 <variablelist class='network-directives'
>
1023 <term><varname>PrivateKey=
</varname></term>
1025 <para>The Base64 encoded private key for the interface. It can be
1026 generated using the
<command>wg genkey
</command> command
1027 (see
<citerefentry project=
"wireguard"><refentrytitle>wg
</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1028 This option is mandatory to use WireGuard.
1029 Note that because this information is secret, you may want to set
1030 the permissions of the .netdev file to be owned by
<literal>root:systemd-networkd
</literal>
1031 with a
<literal>0640</literal> file mode.
</para>
1035 <term><varname>ListenPort=
</varname></term>
1037 <para>Sets UDP port for listening. Takes either value between
1 and
65535
1038 or
<literal>auto
</literal>. If
<literal>auto
</literal> is specified,
1039 the port is automatically generated based on interface name.
1040 Defaults to
<literal>auto
</literal>.
</para>
1044 <term><varname>FwMark=
</varname></term>
1046 <para>Sets a firewall mark on outgoing WireGuard packets from this interface.
</para>
1053 <title>[WireGuardPeer] Section Options
</title>
1055 <para>The
<literal>[WireGuardPeer]
</literal> section accepts the following
1058 <variablelist class='network-directives'
>
1060 <term><varname>PublicKey=
</varname></term>
1062 <para>Sets a Base64 encoded public key calculated by
<command>wg pubkey
</command>
1063 (see
<citerefentry project=
"wireguard"><refentrytitle>wg
</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1064 from a private key, and usually transmitted out of band to the
1065 author of the configuration file. This option is mandatory for this
1070 <term><varname>PresharedKey=
</varname></term>
1072 <para>Optional preshared key for the interface. It can be generated
1073 by the
<command>wg genpsk
</command> command. This option adds an
1074 additional layer of symmetric-key cryptography to be mixed into the
1075 already existing public-key cryptography, for post-quantum
1077 Note that because this information is secret, you may want to set
1078 the permissions of the .netdev file to be owned by
<literal>root:systemd-networkd
</literal>
1079 with a
<literal>0640</literal> file mode.
</para>
1083 <term><varname>AllowedIPs=
</varname></term>
1085 <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks
1086 from which this peer is allowed to send incoming traffic and to
1087 which outgoing traffic for this peer is directed. The catch-all
1088 0.0.0.0/
0 may be specified for matching all IPv4 addresses, and
1089 ::/
0 may be specified for matching all IPv6 addresses.
</para>
1093 <term><varname>Endpoint=
</varname></term>
1095 <para>Sets an endpoint IP address or hostname, followed by a colon, and then
1096 a port number. This endpoint will be updated automatically once to
1097 the most recent source IP address and port of correctly
1098 authenticated packets from the peer at configuration time.
</para>
1102 <term><varname>PersistentKeepalive=
</varname></term>
1104 <para>Sets a seconds interval, between
1 and
65535 inclusive, of how often
1105 to send an authenticated empty packet to the peer for the purpose
1106 of keeping a stateful firewall or NAT mapping valid persistently.
1107 For example, if the interface very rarely sends traffic, but it
1108 might at anytime receive traffic from a peer, and it is behind NAT,
1109 the interface might benefit from having a persistent keepalive
1110 interval of
25 seconds. If set to
0 or
"off", this option is
1111 disabled. By default or when unspecified, this option is off.
1112 Most users will not need this.
</para>
1119 <title>[Bond] Section Options
</title>
1121 <para>The
<literal>[Bond]
</literal> section accepts the following
1124 <variablelist class='network-directives'
>
1126 <term><varname>Mode=
</varname></term>
1128 <para>Specifies one of the bonding policies. The default is
1129 <literal>balance-rr
</literal> (round robin). Possible values are
1130 <literal>balance-rr
</literal>,
1131 <literal>active-backup
</literal>,
1132 <literal>balance-xor
</literal>,
1133 <literal>broadcast
</literal>,
1134 <literal>802.3ad
</literal>,
1135 <literal>balance-tlb
</literal>, and
1136 <literal>balance-alb
</literal>.
1142 <term><varname>TransmitHashPolicy=
</varname></term>
1144 <para>Selects the transmit hash policy to use for slave
1145 selection in balance-xor,
802.3ad, and tlb modes. Possible
1147 <literal>layer2
</literal>,
1148 <literal>layer3+
4</literal>,
1149 <literal>layer2+
3</literal>,
1150 <literal>encap2+
3</literal>, and
1151 <literal>encap3+
4</literal>.
1157 <term><varname>LACPTransmitRate=
</varname></term>
1159 <para>Specifies the rate with which link partner transmits
1160 Link Aggregation Control Protocol Data Unit packets in
1161 802.3ad mode. Possible values are
<literal>slow
</literal>,
1162 which requests partner to transmit LACPDUs every
30 seconds,
1163 and
<literal>fast
</literal>, which requests partner to
1164 transmit LACPDUs every second. The default value is
1165 <literal>slow
</literal>.
</para>
1170 <term><varname>MIIMonitorSec=
</varname></term>
1172 <para>Specifies the frequency that Media Independent
1173 Interface link monitoring will occur. A value of zero
1174 disables MII link monitoring. This value is rounded down to
1175 the nearest millisecond. The default value is
0.
</para>
1180 <term><varname>UpDelaySec=
</varname></term>
1182 <para>Specifies the delay before a link is enabled after a
1183 link up status has been detected. This value is rounded down
1184 to a multiple of MIIMonitorSec. The default value is
1190 <term><varname>DownDelaySec=
</varname></term>
1192 <para>Specifies the delay before a link is disabled after a
1193 link down status has been detected. This value is rounded
1194 down to a multiple of MIIMonitorSec. The default value is
1200 <term><varname>LearnPacketIntervalSec=
</varname></term>
1202 <para>Specifies the number of seconds between instances where the bonding
1203 driver sends learning packets to each slave peer switch.
1204 The valid range is
1–
0x7fffffff; the default value is
1. This option
1205 has an effect only for the balance-tlb and balance-alb modes.
</para>
1210 <term><varname>AdSelect=
</varname></term>
1212 <para>Specifies the
802.3ad aggregation selection logic to use. Possible values are
1213 <literal>stable
</literal>,
1214 <literal>bandwidth
</literal> and
1215 <literal>count
</literal>.
1221 <term><varname>FailOverMACPolicy=
</varname></term>
1223 <para>Specifies whether the active-backup mode should set all slaves to
1224 the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1225 bond's MAC address in accordance with the selected policy. The default policy is none.
1227 <literal>none
</literal>,
1228 <literal>active
</literal> and
1229 <literal>follow
</literal>.
1235 <term><varname>ARPValidate=
</varname></term>
1237 <para>Specifies whether or not ARP probes and replies should be
1238 validated in any mode that supports ARP monitoring, or whether
1239 non-ARP traffic should be filtered (disregarded) for link
1240 monitoring purposes. Possible values are
1241 <literal>none
</literal>,
1242 <literal>active
</literal>,
1243 <literal>backup
</literal> and
1244 <literal>all
</literal>.
1250 <term><varname>ARPIntervalSec=
</varname></term>
1252 <para>Specifies the ARP link monitoring frequency in milliseconds.
1253 A value of
0 disables ARP monitoring. The default value is
0.
1259 <term><varname>ARPIPTargets=
</varname></term>
1261 <para>Specifies the IP addresses to use as ARP monitoring peers when
1262 ARPIntervalSec is greater than
0. These are the targets of the ARP request
1263 sent to determine the health of the link to the targets.
1264 Specify these values in IPv4 dotted decimal format. At least one IP
1265 address must be given for ARP monitoring to function. The
1266 maximum number of targets that can be specified is
16. The
1267 default value is no IP addresses.
1273 <term><varname>ARPAllTargets=
</varname></term>
1275 <para>Specifies the quantity of ARPIPTargets that must be reachable
1276 in order for the ARP monitor to consider a slave as being up.
1277 This option affects only active-backup mode for slaves with
1278 ARPValidate enabled. Possible values are
1279 <literal>any
</literal> and
1280 <literal>all
</literal>.
1286 <term><varname>PrimaryReselectPolicy=
</varname></term>
1288 <para>Specifies the reselection policy for the primary slave. This
1289 affects how the primary slave is chosen to become the active slave
1290 when failure of the active slave or recovery of the primary slave
1291 occurs. This option is designed to prevent flip-flopping between
1292 the primary slave and other slaves. Possible values are
1293 <literal>always
</literal>,
1294 <literal>better
</literal> and
1295 <literal>failure
</literal>.
1301 <term><varname>ResendIGMP=
</varname></term>
1303 <para>Specifies the number of IGMP membership reports to be issued after
1304 a failover event. One membership report is issued immediately after
1305 the failover, subsequent packets are sent in each
200ms interval.
1306 The valid range is
0–
255. Defaults to
1. A value of
0
1307 prevents the IGMP membership report from being issued in response
1308 to the failover event.
1314 <term><varname>PacketsPerSlave=
</varname></term>
1316 <para>Specify the number of packets to transmit through a slave before
1317 moving to the next one. When set to
0, then a slave is chosen at
1318 random. The valid range is
0–
65535. Defaults to
1. This option
1319 only has effect when in balance-rr mode.
1325 <term><varname>GratuitousARP=
</varname></term>
1327 <para>Specify the number of peer notifications (gratuitous ARPs and
1328 unsolicited IPv6 Neighbor Advertisements) to be issued after a
1329 failover event. As soon as the link is up on the new slave,
1330 a peer notification is sent on the bonding device and each
1331 VLAN sub-device. This is repeated at each link monitor interval
1332 (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1333 greater than
1. The valid range is
0–
255. The default value is
1.
1334 These options affect only the active-backup mode.
1340 <term><varname>AllSlavesActive=
</varname></term>
1342 <para>A boolean. Specifies that duplicate frames (received on inactive ports)
1343 should be dropped when false, or delivered when true. Normally, bonding will drop
1344 duplicate frames (received on inactive ports), which is desirable for
1345 most users. But there are some times it is nice to allow duplicate
1346 frames to be delivered. The default value is false (drop duplicate frames
1347 received on inactive ports).
1353 <term><varname>MinLinks=
</varname></term>
1355 <para>Specifies the minimum number of links that must be active before
1356 asserting carrier. The default value is
0.
1362 <para>For more detail information see
1363 <ulink url=
"https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1364 Linux Ethernet Bonding Driver HOWTO
</ulink></para>
1369 <title>Example
</title>
1371 <title>/etc/systemd/network/
25-bridge.netdev
</title>
1373 <programlisting>[NetDev]
1375 Kind=bridge
</programlisting>
1379 <title>/etc/systemd/network/
25-vlan1.netdev
</title>
1381 <programlisting>[Match]
1389 Id=
1</programlisting>
1392 <title>/etc/systemd/network/
25-ipip.netdev
</title>
1393 <programlisting>[NetDev]
1399 Local=
192.168.223.238
1400 Remote=
192.169.224.239
1401 TTL=
64</programlisting>
1404 <title>/etc/systemd/network/
25-tap.netdev
</title>
1405 <programlisting>[NetDev]
1411 PacketInfo=true
</programlisting> </example>
1414 <title>/etc/systemd/network/
25-sit.netdev
</title>
1415 <programlisting>[NetDev]
1422 Remote=
10.65.223.239</programlisting>
1426 <title>/etc/systemd/network/
25-gre.netdev
</title>
1427 <programlisting>[NetDev]
1434 Remote=
10.65.223.239</programlisting>
1438 <title>/etc/systemd/network/
25-vti.netdev
</title>
1440 <programlisting>[NetDev]
1447 Remote=
10.65.223.239</programlisting>
1451 <title>/etc/systemd/network/
25-veth.netdev
</title>
1452 <programlisting>[NetDev]
1457 Name=veth-peer
</programlisting>
1461 <title>/etc/systemd/network/
25-bond.netdev
</title>
1462 <programlisting>[NetDev]
1468 TransmitHashPolicy=layer3+
4
1470 LACPTransmitRate=fast
1475 <title>/etc/systemd/network/
25-dummy.netdev
</title>
1476 <programlisting>[NetDev]
1479 MACAddress=
12:
34:
56:
78:
9a:bc
</programlisting>
1482 <title>/etc/systemd/network/
25-vrf.netdev
</title>
1483 <para>Create a VRF interface with table
42.
</para>
1484 <programlisting>[NetDev]
1489 Table=
42</programlisting>
1493 <title>/etc/systemd/network/
25-macvtap.netdev
</title>
1494 <para>Create a MacVTap device.
</para>
1495 <programlisting>[NetDev]
1501 <title>/etc/systemd/network/
25-wireguard.netdev
</title>
1502 <programlisting>[NetDev]
1507 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
1511 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
1512 AllowedIPs=fd31:bf08:
57cb::/
48,
192.168.26.0/
24
1513 Endpoint=wireguard.example.com:
51820</programlisting>
1517 <title>See Also
</title>
1519 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1520 <citerefentry><refentrytitle>systemd-networkd
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1521 <citerefentry><refentrytitle>systemd.link
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1522 <citerefentry><refentrytitle>systemd.network
</refentrytitle><manvolnum>5</manvolnum></citerefentry>