man/systemd.netdev.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd.network</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd.netdev</refentrytitle>
  16     <manvolnum>5</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd.netdev</refname>
  21     <refpurpose>Virtual Network Device configuration</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  26   </refsynopsisdiv>
  27
  28   <refsect1>
  29     <title>Description</title>
  30
  31     <para>A plain ini-style text file that encodes configuration about a virtual network device, used by
  32     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  33     See <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  34     for a general description of the syntax.</para>
  35
  36     <para>The main Virtual Network Device file must have the extension <filename>.netdev</filename>;
  37     other extensions are ignored. Virtual network devices are created as soon as networkd is
  38     started. If a netdev with the specified name already exists, networkd will use that as-is rather
  39     than create its own. Note that the settings of the pre-existing netdev will not be changed by
  40     networkd.</para>
  41
  42     <para>The <filename>.netdev</filename> files are read from the files located in the system network
  43     directory <filename>/usr/lib/systemd/network</filename> and
  44     <filename>/usr/local/lib/systemd/network</filename>, the volatile runtime network directory
  45     <filename>/run/systemd/network</filename> and the local administration network directory
  46     <filename>/etc/systemd/network</filename>. All configuration files are collectively sorted and
  47     processed in alphanumeric order, regardless of the directories in which they live. However, files
  48     with identical filenames replace each other. It is recommended that each filename is prefixed with
  49     a number smaller than <literal>70</literal> (e.g. <filename>10-vlan.netdev</filename>). Otherwise,
  50     <filename>.netdev</filename> files generated by
  51     <citerefentry><refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  52     may take precedence over user configured files. Files in <filename>/etc/</filename> have the
  53     highest priority, files in <filename>/run/</filename> take precedence over files with the same name
  54     in <filename>/usr/lib/</filename>. This can be used to override a system-supplied configuration
  55     file with a local file if needed. As a special case, an empty file (file size 0) or symlink with
  56     the same name pointing to <filename>/dev/null</filename> disables the configuration file entirely
  57     (it is "masked").</para>
  58
  59     <para>Along with the netdev file <filename>foo.netdev</filename>, a "drop-in" directory
  60     <filename>foo.netdev.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  61     from this directory will be merged in the alphanumeric order and parsed after the main file itself
  62     has been parsed. This is useful to alter or add configuration settings, without having to modify
  63     the main configuration file. Each drop-in file must have appropriate section headers.</para>
  64
  65     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  66     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  67     <filename>/run/systemd/network</filename> directories. Drop-in files in
  68     <filename>/etc/</filename> take precedence over those in <filename>/run/</filename> which in turn
  69     take precedence over those in <filename>/usr/lib/</filename>. Drop-in files under any of these
  70     directories take precedence over the main netdev file wherever located. (Of course, since
  71     <filename>/run/</filename> is temporary and <filename>/usr/lib/</filename> is for vendors, it is
  72     unlikely drop-ins should be used in either of those places.)</para>
  73   </refsect1>
  74
  75   <refsect1>
  76     <title>Supported netdev kinds</title>
  77
  78     <para>The following kinds of virtual network devices may be
  79     configured in <filename>.netdev</filename> files:</para>
  80
  81     <table>
  82       <title>Supported kinds of virtual network devices</title>
  83
  84       <tgroup cols='2'>
  85         <colspec colname='kind' />
  86         <colspec colname='explanation' />
  87         <thead><row>
  88           <entry>Kind</entry>
  89           <entry>Description</entry>
  90         </row></thead>
  91         <tbody>
  92           <row><entry><varname>bond</varname></entry>
  93           <entry>A bond device is an aggregation of all its slave devices. See <ulink url="https://docs.kernel.org/networking/bonding.html">Linux Ethernet Bonding Driver HOWTO</ulink> for details.</entry></row>
  94
  95           <row><entry><varname>bridge</varname></entry>
  96           <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>
  97
  98           <row><entry><varname>dummy</varname></entry>
  99           <entry>A dummy device drops all packets sent to it.</entry></row>
 100
 101           <row><entry><varname>gre</varname></entry>
 102           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details. Name <literal>gre0</literal> should not be used, as the kernel creates a device with this name when the corresponding kernel module is loaded.</entry></row>
 103
 104           <row><entry><varname>gretap</varname></entry>
 105           <entry>A Level 2 GRE tunnel over IPv4. Name <literal>gretap0</literal> should not be used, as the kernel creates a device with this name when the corresponding kernel module is loaded.</entry></row>
 106
 107           <row><entry><varname>erspan</varname></entry>
 108           <entry>ERSPAN mirrors traffic on one or more source ports and delivers the mirrored traffic to one or more destination ports on another switch. The traffic is encapsulated in generic routing encapsulation (GRE) and is therefore routable across a layer 3 network between the source switch and the destination switch. Name <literal>erspan0</literal> should not be used, as the kernel creates a device with this name when the corresponding kernel module is loaded.</entry></row>
 109
 110           <row><entry><varname>ip6gre</varname></entry>
 111           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 112
 113           <row><entry><varname>ip6tnl</varname></entry>
 114           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 115
 116           <row><entry><varname>ip6gretap</varname></entry>
 117           <entry>A Level 2 GRE tunnel over IPv6.</entry></row>
 118
 119           <row><entry><varname>ipip</varname></entry>
 120           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 121
 122           <row><entry><varname>ipvlan</varname></entry>
 123           <entry>An IPVLAN device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 124
 125           <row><entry><varname>ipvtap</varname></entry>
 126           <entry>An IPVTAP device is a stacked device which receives packets from its underlying device based on IP address filtering and can be accessed using the tap user space interface.</entry></row>
 127
 128           <row><entry><varname>macvlan</varname></entry>
 129           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 130
 131           <row><entry><varname>macvtap</varname></entry>
 132           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 133
 134           <row><entry><varname>sit</varname></entry>
 135           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 136
 137           <row><entry><varname>tap</varname></entry>
 138           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 139
 140           <row><entry><varname>tun</varname></entry>
 141           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 142
 143           <row><entry><varname>veth</varname></entry>
 144           <entry>An Ethernet tunnel between a pair of network devices.</entry></row>
 145
 146           <row><entry><varname>vlan</varname></entry>
 147           <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>
 148
 149           <row><entry><varname>vti</varname></entry>
 150           <entry>An IPv4 over IPSec tunnel.</entry></row>
 151
 152           <row><entry><varname>vti6</varname></entry>
 153           <entry>An IPv6 over IPSec tunnel.</entry></row>
 154
 155           <row><entry><varname>vxlan</varname></entry>
 156           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 157
 158           <row><entry><varname>geneve</varname></entry>
 159           <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.</entry></row>
 160
 161           <row><entry><varname>l2tp</varname></entry>
 162           <entry>A Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to support virtual private networks (VPNs) or as part of the delivery of services by ISPs. It does not provide any encryption or confidentiality by itself</entry></row>
 163
 164           <row><entry><varname>macsec</varname></entry>
 165           <entry>Media Access Control Security (MACsec) is an 802.1AE IEEE industry-standard security technology that provides secure communication for all traffic on Ethernet links. MACsec provides point-to-point security on Ethernet links between directly connected nodes and is capable of identifying and preventing most security threats.</entry></row>
 166
 167           <row><entry><varname>vrf</varname></entry>
 168           <entry>A Virtual Routing and Forwarding (<ulink url="https://docs.kernel.org/networking/vrf.html">VRF</ulink>) interface to create separate routing and forwarding domains.</entry></row>
 169
 170           <row><entry><varname>vcan</varname></entry>
 171           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 172
 173           <row><entry><varname>vxcan</varname></entry>
 174           <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.
 175           </entry></row>
 176
 177           <row><entry><varname>wireguard</varname></entry>
 178           <entry>WireGuard Secure Network Tunnel.</entry></row>
 179
 180           <row><entry><varname>nlmon</varname></entry>
 181           <entry>A Netlink monitor device. Use an nlmon device when you want to monitor system Netlink messages.</entry></row>
 182
 183           <row><entry><varname>fou</varname></entry>
 184           <entry>Foo-over-UDP tunneling.</entry></row>
 185
 186           <row><entry><varname>xfrm</varname></entry>
 187           <entry>A virtual tunnel interface like vti/vti6 but with several advantages.</entry></row>
 188
 189           <row><entry><varname>ifb</varname></entry>
 190           <entry>The Intermediate Functional Block (ifb) pseudo network interface acts as a QoS concentrator for multiple different sources of traffic.</entry></row>
 191
 192           <row><entry><varname>bareudp</varname></entry>
 193           <entry>Bare UDP tunnels provide a generic L3 encapsulation support for tunnelling different L3 protocols like MPLS, IP etc. inside of a UDP tunnel.</entry></row>
 194
 195           <row><entry><varname>batadv</varname></entry>
 196           <entry><ulink url="https://www.open-mesh.org/projects/open-mesh/wiki">B.A.T.M.A.N. Advanced</ulink> is a routing protocol for multi-hop mobile ad-hoc networks which operates on layer 2.</entry></row>
 197
 198           <row><entry><varname>ipoib</varname></entry>
 199           <entry>An IP over Infiniband subinterface.</entry></row>
 200
 201           <row><entry><varname>wlan</varname></entry>
 202           <entry>A virtual wireless network (WLAN) interface.</entry></row>
 203         </tbody>
 204       </tgroup>
 205     </table>
 206
 207   </refsect1>
 208
 209   <refsect1>
 210     <title>[Match] Section Options</title>
 211
 212     <para>A virtual network device is only created if the [Match] section matches the current
 213     environment, or if the section is empty. The following keys are accepted:</para>
 214
 215     <variablelist class='network-directives'>
 216       <xi:include href="systemd.link.xml" xpointer="host" />
 217       <xi:include href="systemd.link.xml" xpointer="virtualization" />
 218       <xi:include href="systemd.link.xml" xpointer="kernel-command-line" />
 219       <xi:include href="systemd.link.xml" xpointer="kernel-version" />
 220       <xi:include href="systemd.link.xml" xpointer="credential" />
 221       <xi:include href="systemd.link.xml" xpointer="architecture" />
 222       <xi:include href="systemd.link.xml" xpointer="firmware" />
 223     </variablelist>
 224   </refsect1>
 225
 226   <refsect1>
 227     <title>[NetDev] Section Options</title>
 228
 229     <para>The [NetDev] section accepts the
 230     following keys:</para>
 231
 232     <variablelist class='network-directives'>
 233       <varlistentry>
 234         <term><varname>Description=</varname></term>
 235         <listitem>
 236           <para>A free-form description of the netdev.</para>
 237
 238         <xi:include href="version-info.xml" xpointer="v215"/>
 239         </listitem>
 240       </varlistentry>
 241       <varlistentry>
 242         <term><varname>Name=</varname></term>
 243         <listitem>
 244           <para>The interface name used when creating the netdev.
 245           This setting is compulsory.</para>
 246
 247           <xi:include href="version-info.xml" xpointer="v211"/>
 248         </listitem>
 249       </varlistentry>
 250       <varlistentry>
 251         <term><varname>Kind=</varname></term>
 252         <listitem>
 253           <para>The netdev kind. This setting is compulsory. See the
 254           <literal>Supported netdev kinds</literal> section for the
 255           valid keys.</para>
 256
 257           <xi:include href="version-info.xml" xpointer="v211"/>
 258         </listitem>
 259       </varlistentry>
 260       <varlistentry>
 261         <term><varname>MTUBytes=</varname></term>
 262         <listitem>
 263           <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M, G
 264           are supported and are understood to the base of 1024. For <literal>tun</literal> or
 265           <literal>tap</literal> devices, <varname>MTUBytes=</varname> setting is not currently supported in
 266           [NetDev] section. Please specify it in [Link] section of
 267           corresponding
 268           <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 269           files.</para>
 270
 271           <xi:include href="version-info.xml" xpointer="v215"/>
 272         </listitem>
 273       </varlistentry>
 274       <varlistentry>
 275         <term><varname>MACAddress=</varname></term>
 276         <listitem>
 277           <para>Specifies the MAC address to use for the device, or takes the special value
 278           <literal>none</literal>. When <literal>none</literal>, <command>systemd-networkd</command>
 279           does not request the MAC address for the device, and the kernel will assign a random MAC
 280           address. For <literal>tun</literal>, <literal>tap</literal>, or <literal>l2tp</literal>
 281           devices, the <varname>MACAddress=</varname> setting in the [NetDev] section is not
 282           supported and will be ignored. Please specify it in the [Link] section of the corresponding
 283           <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 284           file. If this option is not set, <literal>vlan</literal> device inherits the MAC address of
 285           the master interface. For other kind of netdevs, if this option is not set, then the MAC
 286           address is generated based on the interface name and the
 287           <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 288           </para>
 289           <para>Note, even if <literal>none</literal> is specified, <command>systemd-udevd</command>
 290           will assign the persistent MAC address for the device, as <filename>99-default.link</filename>
 291           has <varname>MACAddressPolicy=persistent</varname>. So, it is also necessary to create a
 292           custom .link file for the device, if the MAC address assignment is not desired.</para>
 293
 294           <xi:include href="version-info.xml" xpointer="v215"/>
 295         </listitem>
 296       </varlistentry>
 297     </variablelist>
 298   </refsect1>
 299
 300   <refsect1>
 301     <title>[Bridge] Section Options</title>
 302
 303     <para>The [Bridge] section only applies for
 304     netdevs of kind <literal>bridge</literal>, and accepts the
 305     following keys:</para>
 306
 307     <variablelist class='network-directives'>
 308       <varlistentry>
 309         <term><varname>HelloTimeSec=</varname></term>
 310         <listitem>
 311           <para>HelloTimeSec specifies the number of seconds between two hello packets
 312           sent out by the root bridge and the designated bridges. Hello packets are
 313           used to communicate information about the topology throughout the entire
 314           bridged local area network.</para>
 315
 316           <xi:include href="version-info.xml" xpointer="v227"/>
 317         </listitem>
 318       </varlistentry>
 319       <varlistentry>
 320         <term><varname>MaxAgeSec=</varname></term>
 321         <listitem>
 322           <para>MaxAgeSec specifies the number of seconds of maximum message age.
 323           If the last seen (received) hello packet is more than this number of
 324           seconds old, the bridge in question will start the takeover procedure
 325           in attempt to become the Root Bridge itself.</para>
 326
 327           <xi:include href="version-info.xml" xpointer="v227"/>
 328         </listitem>
 329       </varlistentry>
 330       <varlistentry>
 331         <term><varname>ForwardDelaySec=</varname></term>
 332         <listitem>
 333           <para>ForwardDelaySec specifies the number of seconds spent in each
 334           of the Listening and Learning states before the Forwarding state is entered.</para>
 335
 336           <xi:include href="version-info.xml" xpointer="v227"/>
 337         </listitem>
 338       </varlistentry>
 339       <varlistentry>
 340         <term><varname>AgeingTimeSec=</varname></term>
 341         <listitem>
 342           <para>This specifies the number of seconds a MAC Address will be kept in
 343           the forwarding database after having a packet received from this MAC Address.</para>
 344
 345           <xi:include href="version-info.xml" xpointer="v232"/>
 346         </listitem>
 347       </varlistentry>
 348       <varlistentry>
 349         <term><varname>Priority=</varname></term>
 350         <listitem>
 351           <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 352           means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 353
 354           <xi:include href="version-info.xml" xpointer="v232"/>
 355         </listitem>
 356       </varlistentry>
 357       <varlistentry>
 358         <term><varname>GroupForwardMask=</varname></term>
 359         <listitem>
 360           <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 361           local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 362           is performed between the specified bitmask and the exponentiation of 2^X, the
 363           lower nibble of the last octet of the MAC address. For example, a value of 8
 364           would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 365
 366           <xi:include href="version-info.xml" xpointer="v235"/>
 367         </listitem>
 368       </varlistentry>
 369       <varlistentry>
 370         <term><varname>DefaultPVID=</varname></term>
 371         <listitem>
 372           <para>This specifies the default port VLAN ID of a newly attached bridge port.
 373           Set this to an integer in the range 1…4094 or <literal>none</literal> to disable the PVID.</para>
 374
 375           <xi:include href="version-info.xml" xpointer="v232"/>
 376         </listitem>
 377       </varlistentry>
 378       <varlistentry>
 379         <term><varname>MulticastQuerier=</varname></term>
 380         <listitem>
 381           <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 382           If enabled, the kernel will send general ICMP queries from a zero source address.
 383           This feature should allow faster convergence on startup, but it causes some
 384           multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 385           When unset, the kernel's default will be used.
 386           </para>
 387
 388           <xi:include href="version-info.xml" xpointer="v230"/>
 389         </listitem>
 390       </varlistentry>
 391       <varlistentry>
 392         <term><varname>MulticastSnooping=</varname></term>
 393         <listitem>
 394           <para>Takes 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 will be used.
 397           </para>
 398
 399           <xi:include href="version-info.xml" xpointer="v230"/>
 400         </listitem>
 401       </varlistentry>
 402       <varlistentry>
 403         <term><varname>VLANFiltering=</varname></term>
 404         <listitem>
 405           <para>Takes a boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 406           If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's default will be used.
 407           </para>
 408
 409           <xi:include href="version-info.xml" xpointer="v231"/>
 410         </listitem>
 411       </varlistentry>
 412       <varlistentry>
 413         <term><varname>VLANProtocol=</varname></term>
 414         <listitem>
 415           <para>Allows setting the protocol used for VLAN filtering. Takes
 416           <option>802.1q</option> or,
 417           <option>802.1ad</option>, and defaults to unset and kernel's default is used.
 418           </para>
 419
 420           <xi:include href="version-info.xml" xpointer="v246"/>
 421         </listitem>
 422       </varlistentry>
 423       <varlistentry>
 424         <term><varname>STP=</varname></term>
 425         <listitem>
 426           <para>Takes a boolean. This enables the bridge's Spanning Tree Protocol (STP).
 427           When unset, the kernel's default will be used.
 428           </para>
 429
 430           <xi:include href="version-info.xml" xpointer="v232"/>
 431         </listitem>
 432       </varlistentry>
 433       <varlistentry>
 434         <term><varname>MulticastIGMPVersion=</varname></term>
 435         <listitem>
 436           <para>Allows changing bridge's multicast Internet Group Management Protocol (IGMP) version.
 437           Takes an integer 2 or 3. When unset, the kernel's default will be used.
 438           </para>
 439
 440           <xi:include href="version-info.xml" xpointer="v243"/>
 441         </listitem>
 442       </varlistentry>
 443     </variablelist>
 444   </refsect1>
 445
 446   <refsect1>
 447     <title>[VLAN] Section Options</title>
 448
 449     <para>The [VLAN] section only applies for
 450     netdevs of kind <literal>vlan</literal>, and accepts the
 451     following key:</para>
 452
 453     <variablelist class='network-directives'>
 454       <varlistentry>
 455         <term><varname>Id=</varname></term>
 456         <listitem>
 457           <para>The VLAN ID to use. An integer in the range 0…4094.
 458           This setting is compulsory.</para>
 459
 460           <xi:include href="version-info.xml" xpointer="v211"/>
 461         </listitem>
 462       </varlistentry>
 463       <varlistentry>
 464         <term><varname>Protocol=</varname></term>
 465         <listitem>
 466           <para>Allows setting the protocol used for the VLAN interface. Takes <literal>802.1q</literal> or,
 467           <literal>802.1ad</literal>, and defaults to unset and kernel's default is used.</para>
 468
 469         <xi:include href="version-info.xml" xpointer="v248"/>
 470         </listitem>
 471       </varlistentry>
 472       <varlistentry>
 473         <term><varname>GVRP=</varname></term>
 474         <listitem>
 475           <para>Takes a boolean. The Generic VLAN Registration Protocol (GVRP) is a protocol that
 476           allows automatic learning of VLANs on a network.
 477           When unset, the kernel's default will be used.
 478           </para>
 479
 480           <xi:include href="version-info.xml" xpointer="v234"/>
 481         </listitem>
 482       </varlistentry>
 483       <varlistentry>
 484         <term><varname>MVRP=</varname></term>
 485         <listitem>
 486           <para>Takes a boolean. Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 487           Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 488           for automatic configuration of VLAN information on switches. It was defined
 489           in the 802.1ak amendment to 802.1Q-2005. When unset, the kernel's default will be used.
 490           </para>
 491
 492           <xi:include href="version-info.xml" xpointer="v234"/>
 493         </listitem>
 494       </varlistentry>
 495       <varlistentry>
 496         <term><varname>LooseBinding=</varname></term>
 497         <listitem>
 498           <para>Takes a boolean. The VLAN loose binding mode, in which only the operational state is passed
 499           from the parent to the associated VLANs, but the VLAN device state is not changed.
 500           When unset, the kernel's default will be used.</para>
 501
 502           <xi:include href="version-info.xml" xpointer="v234"/>
 503         </listitem>
 504       </varlistentry>
 505       <varlistentry>
 506         <term><varname>ReorderHeader=</varname></term>
 507         <listitem>
 508           <para>Takes a boolean. When enabled, the VLAN reorder header is used and VLAN interfaces behave
 509           like physical interfaces. When unset, the kernel's default will be used.</para>
 510
 511           <xi:include href="version-info.xml" xpointer="v234"/>
 512         </listitem>
 513       </varlistentry>
 514       <varlistentry>
 515         <term><varname>EgressQOSMaps=</varname></term>
 516         <term><varname>IngressQOSMaps=</varname></term>
 517         <listitem>
 518           <para>Defines a mapping of Linux internal packet priority (<constant>SO_PRIORITY</constant>)
 519           to VLAN header PCP field for outgoing and incoming frames, respectively. Takes a
 520           whitespace-separated list of integer pairs, where each integer must be in the range
 521           1…4294967294, in the format <literal>from</literal>-<literal>to</literal>, e.g.,
 522           <literal>21-7 45-5</literal>. Note that <literal>from</literal> must be greater than or equal
 523           to <literal>to</literal>. When unset, the kernel's default will be used.</para>
 524
 525         <xi:include href="version-info.xml" xpointer="v248"/>
 526         </listitem>
 527       </varlistentry>
 528     </variablelist>
 529   </refsect1>
 530
 531   <refsect1>
 532     <title>[MACVLAN] Section Options</title>
 533
 534     <para>The [MACVLAN] section only applies for
 535     netdevs of kind <literal>macvlan</literal>, and accepts the
 536     following key:</para>
 537
 538     <variablelist class='network-directives'>
 539       <varlistentry>
 540         <term><varname>Mode=</varname></term>
 541         <listitem>
 542           <para>The MACVLAN mode to use. The supported options are
 543           <literal>private</literal>,
 544           <literal>vepa</literal>,
 545           <literal>bridge</literal>,
 546           <literal>passthru</literal>, and
 547           <literal>source</literal>.
 548           </para>
 549
 550           <xi:include href="version-info.xml" xpointer="v211"/>
 551         </listitem>
 552       </varlistentry>
 553       <varlistentry>
 554         <term><varname>SourceMACAddress=</varname></term>
 555         <listitem>
 556           <para>A whitespace-separated list of remote hardware addresses allowed on the MACVLAN. This
 557           option only has an effect in source mode. Use full colon-, hyphen- or dot-delimited
 558           hexadecimal. This option may appear more than once, in which case the lists are merged. If
 559           the empty string is assigned to this option, the list of hardware addresses defined prior
 560           to this is reset. Defaults to unset.</para>
 561
 562           <xi:include href="version-info.xml" xpointer="v246"/>
 563         </listitem>
 564       </varlistentry>
 565       <varlistentry>
 566         <term><varname>BroadcastMulticastQueueLength=</varname></term>
 567         <listitem>
 568           <para>Specifies the length of the receive queue for broadcast/multicast packets. An unsigned
 569           integer in the range 0…4294967294. Defaults to unset.</para>
 570
 571           <xi:include href="version-info.xml" xpointer="v248"/>
 572         </listitem>
 573       </varlistentry>
 574     </variablelist>
 575   </refsect1>
 576
 577   <refsect1>
 578     <title>[MACVTAP] Section Options</title>
 579
 580     <para>The [MACVTAP] section applies for netdevs of kind <literal>macvtap</literal> and accepts the same
 581     keys as [MACVLAN].</para>
 582   </refsect1>
 583
 584   <refsect1>
 585     <title>[IPVLAN] Section Options</title>
 586
 587     <para>The [IPVLAN] section only applies for
 588     netdevs of kind <literal>ipvlan</literal>, and accepts the
 589     following key:</para>
 590
 591     <variablelist class='network-directives'>
 592       <varlistentry>
 593         <term><varname>Mode=</varname></term>
 594         <listitem>
 595           <para>The IPVLAN mode to use. The supported options are
 596           <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 597           </para>
 598
 599           <xi:include href="version-info.xml" xpointer="v219"/>
 600         </listitem>
 601       </varlistentry>
 602       <varlistentry>
 603         <term><varname>Flags=</varname></term>
 604         <listitem>
 605           <para>The IPVLAN flags to use. The supported options are
 606           <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 607           </para>
 608
 609           <xi:include href="version-info.xml" xpointer="v237"/>
 610         </listitem>
 611       </varlistentry>
 612     </variablelist>
 613   </refsect1>
 614
 615   <refsect1>
 616     <title>[IPVTAP] Section Options</title>
 617
 618     <para>The [IPVTAP] section only applies for netdevs of kind <literal>ipvtap</literal> and accepts the
 619     same keys as [IPVLAN].</para>
 620   </refsect1>
 621
 622   <refsect1>
 623     <title>[VXLAN] Section Options</title>
 624
 625     <para>The [VXLAN] section only applies for
 626     netdevs of kind <literal>vxlan</literal>, and accepts the
 627     following keys:</para>
 628
 629     <variablelist class='network-directives'>
 630       <varlistentry>
 631         <term><varname>VNI=</varname></term>
 632         <listitem>
 633           <para>The VXLAN Network Identifier (or VXLAN Segment ID). Takes a number in the range 1…16777215.</para>
 634
 635         <xi:include href="version-info.xml" xpointer="v243"/>
 636         </listitem>
 637       </varlistentry>
 638       <varlistentry>
 639         <term><varname>Remote=</varname></term>
 640         <listitem>
 641           <para>Configures destination IP address.</para>
 642
 643         <xi:include href="version-info.xml" xpointer="v233"/>
 644         </listitem>
 645       </varlistentry>
 646       <varlistentry>
 647         <term><varname>Local=</varname></term>
 648         <listitem>
 649           <para>Configures local IP address. It must be an address on the underlying interface of the
 650           VXLAN interface, or one of the special values <literal>ipv4_link_local</literal>,
 651           <literal>ipv6_link_local</literal>, <literal>dhcp4</literal>, <literal>dhcp6</literal>, and
 652           <literal>slaac</literal>. If one of the special values is specified, an address which matches
 653           the corresponding type on the underlying interface will be used. Defaults to unset.</para>
 654
 655           <xi:include href="version-info.xml" xpointer="v233"/>
 656         </listitem>
 657       </varlistentry>
 658       <varlistentry>
 659         <term><varname>Group=</varname></term>
 660         <listitem>
 661           <para>Configures VXLAN multicast group IP address. All members of a VXLAN must use the same
 662           multicast group address.</para>
 663
 664           <xi:include href="version-info.xml" xpointer="v243"/>
 665         </listitem>
 666       </varlistentry>
 667       <varlistentry>
 668         <term><varname>TOS=</varname></term>
 669         <listitem>
 670           <para>The Type Of Service byte value for a vxlan interface.</para>
 671
 672         <xi:include href="version-info.xml" xpointer="v215"/>
 673         </listitem>
 674       </varlistentry>
 675       <varlistentry>
 676         <term><varname>TTL=</varname></term>
 677         <listitem>
 678           <para>A fixed Time To Live N on Virtual eXtensible Local Area Network packets.
 679           Takes <literal>inherit</literal> or a number in the range 0…255. 0 is a special
 680           value meaning inherit the inner protocol's TTL value. <literal>inherit</literal>
 681           means that it will inherit the outer protocol's TTL value.</para>
 682
 683           <xi:include href="version-info.xml" xpointer="v215"/>
 684         </listitem>
 685       </varlistentry>
 686       <varlistentry>
 687         <term><varname>MacLearning=</varname></term>
 688         <listitem>
 689           <para>Takes a boolean. When true, enables dynamic MAC learning
 690           to discover remote MAC addresses.</para>
 691
 692           <xi:include href="version-info.xml" xpointer="v215"/>
 693         </listitem>
 694       </varlistentry>
 695       <varlistentry>
 696         <term><varname>FDBAgeingSec=</varname></term>
 697         <listitem>
 698           <para>The lifetime of Forwarding Database entry learnt by
 699           the kernel, in seconds.</para>
 700
 701           <xi:include href="version-info.xml" xpointer="v218"/>
 702         </listitem>
 703       </varlistentry>
 704       <varlistentry>
 705         <term><varname>MaximumFDBEntries=</varname></term>
 706         <listitem>
 707           <para>Configures maximum number of FDB entries.</para>
 708
 709         <xi:include href="version-info.xml" xpointer="v228"/>
 710         </listitem>
 711       </varlistentry>
 712       <varlistentry>
 713         <term><varname>ReduceARPProxy=</varname></term>
 714         <listitem>
 715           <para>Takes a boolean. When true, bridge-connected VXLAN tunnel endpoint answers ARP requests from
 716           the local bridge on behalf of remote
 717           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 718             Distributed Overlay Virtual Ethernet (DOVE)</ulink>
 719           clients. Defaults to false.</para>
 720
 721           <xi:include href="version-info.xml" xpointer="v233"/>
 722         </listitem>
 723       </varlistentry>
 724       <varlistentry>
 725         <term><varname>L2MissNotification=</varname></term>
 726         <listitem>
 727           <para>Takes a boolean. When true, enables netlink LLADDR miss
 728           notifications.</para>
 729
 730           <xi:include href="version-info.xml" xpointer="v218"/>
 731         </listitem>
 732       </varlistentry>
 733       <varlistentry>
 734         <term><varname>L3MissNotification=</varname></term>
 735         <listitem>
 736           <para>Takes a boolean. When true, enables netlink IP address miss notifications.</para>
 737
 738         <xi:include href="version-info.xml" xpointer="v218"/>
 739         </listitem>
 740       </varlistentry>
 741       <varlistentry>
 742         <term><varname>RouteShortCircuit=</varname></term>
 743         <listitem>
 744           <para>Takes a boolean. When true, route short circuiting is turned
 745           on.</para>
 746
 747           <xi:include href="version-info.xml" xpointer="v218"/>
 748         </listitem>
 749       </varlistentry>
 750       <varlistentry>
 751         <term><varname>UDPChecksum=</varname></term>
 752         <listitem>
 753           <para>Takes a boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 754
 755         <xi:include href="version-info.xml" xpointer="v220"/>
 756         </listitem>
 757       </varlistentry>
 758       <varlistentry>
 759         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 760         <listitem>
 761           <para>Takes a boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 762
 763         <xi:include href="version-info.xml" xpointer="v220"/>
 764         </listitem>
 765       </varlistentry>
 766       <varlistentry>
 767         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 768         <listitem>
 769           <para>Takes a boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 770
 771         <xi:include href="version-info.xml" xpointer="v220"/>
 772         </listitem>
 773       </varlistentry>
 774       <varlistentry>
 775         <term><varname>RemoteChecksumTx=</varname></term>
 776         <listitem>
 777           <para>Takes a boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 778
 779         <xi:include href="version-info.xml" xpointer="v232"/>
 780         </listitem>
 781       </varlistentry>
 782       <varlistentry>
 783         <term><varname>RemoteChecksumRx=</varname></term>
 784         <listitem>
 785           <para>Takes a boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 786
 787         <xi:include href="version-info.xml" xpointer="v232"/>
 788         </listitem>
 789       </varlistentry>
 790       <varlistentry>
 791         <term><varname>GroupPolicyExtension=</varname></term>
 792         <listitem>
 793           <para>Takes a boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 794           across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 795           <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 796           VXLAN Group Policy </ulink> document. Defaults to false.</para>
 797
 798           <xi:include href="version-info.xml" xpointer="v224"/>
 799         </listitem>
 800       </varlistentry>
 801       <varlistentry>
 802         <term><varname>GenericProtocolExtension=</varname></term>
 803         <listitem>
 804           <para>Takes a boolean. When true, Generic Protocol Extension extends the existing VXLAN protocol
 805           to provide protocol typing, OAM, and versioning capabilities. For details about the VXLAN GPE
 806           Header, see the <ulink url="https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-07">
 807           Generic Protocol Extension for VXLAN </ulink> document. If destination port is not specified and
 808           Generic Protocol Extension is set then default port of 4790 is used. Defaults to false.</para>
 809
 810           <xi:include href="version-info.xml" xpointer="v243"/>
 811         </listitem>
 812       </varlistentry>
 813       <varlistentry>
 814         <term><varname>DestinationPort=</varname></term>
 815         <listitem>
 816           <para>Configures the default destination UDP port. If the destination port is not specified then
 817           Linux kernel default will be used. Set to 4789 to get the IANA assigned value.</para>
 818
 819           <xi:include href="version-info.xml" xpointer="v229"/>
 820         </listitem>
 821       </varlistentry>
 822       <varlistentry>
 823         <term><varname>PortRange=</varname></term>
 824         <listitem>
 825           <para>Configures the source port range for the VXLAN. The kernel assigns the source UDP port based
 826           on the flow to help the receiver to do load balancing. When this option is not set, the normal
 827           range of local UDP ports is used.</para>
 828
 829           <xi:include href="version-info.xml" xpointer="v229"/>
 830         </listitem>
 831       </varlistentry>
 832       <varlistentry>
 833         <term><varname>FlowLabel=</varname></term>
 834         <listitem>
 835           <para>Specifies the flow label to use in outgoing packets.
 836           The valid range is 0-1048575.
 837           </para>
 838
 839           <xi:include href="version-info.xml" xpointer="v234"/>
 840         </listitem>
 841       </varlistentry>
 842       <varlistentry>
 843         <term><varname>IPDoNotFragment=</varname></term>
 844         <listitem>
 845           <para>Allows setting the IPv4 Do not Fragment (DF) bit in outgoing packets, or to inherit its
 846           value from the IPv4 inner header. Takes a boolean value, or <literal>inherit</literal>. Set
 847           to <literal>inherit</literal> if the encapsulated protocol is IPv6. When unset, the kernel's
 848           default will be used.</para>
 849
 850           <xi:include href="version-info.xml" xpointer="v243"/>
 851         </listitem>
 852       </varlistentry>
 853       <varlistentry>
 854         <term><varname>Independent=</varname></term>
 855         <listitem>
 856           <para>Takes a boolean. When true, the vxlan interface is created without any underlying network
 857           interface. Defaults to false, which means that a .network file that requests this VXLAN interface
 858           using <varname>VXLAN=</varname> is required for the VXLAN to be created.</para>
 859
 860           <xi:include href="version-info.xml" xpointer="v247"/>
 861         </listitem>
 862       </varlistentry>
 863     </variablelist>
 864   </refsect1>
 865
 866   <refsect1>
 867     <title>[GENEVE] Section Options</title>
 868
 869     <para>The [GENEVE] section only applies for
 870     netdevs of kind <literal>geneve</literal>, and accepts the
 871     following keys:</para>
 872
 873     <variablelist class='network-directives'>
 874       <varlistentry>
 875         <term><varname>Id=</varname></term>
 876         <listitem>
 877           <para>Specifies the Virtual Network Identifier (VNI) to use, a number between 0 and 16777215. This
 878           field is mandatory.</para>
 879
 880           <xi:include href="version-info.xml" xpointer="v234"/>
 881         </listitem>
 882       </varlistentry>
 883       <varlistentry>
 884         <term><varname>Remote=</varname></term>
 885         <listitem>
 886           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 887
 888         <xi:include href="version-info.xml" xpointer="v234"/>
 889         </listitem>
 890       </varlistentry>
 891       <varlistentry>
 892         <term><varname>TOS=</varname></term>
 893         <listitem>
 894           <para>Specifies the TOS value to use in outgoing packets. Takes a number between 1 and 255.</para>
 895
 896         <xi:include href="version-info.xml" xpointer="v234"/>
 897         </listitem>
 898       </varlistentry>
 899       <varlistentry>
 900         <term><varname>TTL=</varname></term>
 901         <listitem>
 902           <para>Accepts the same values as in the [VXLAN] section, except that when unset
 903           or set to 0, the kernel's default will be used, meaning that packet TTL will be set from
 904           <filename>/proc/sys/net/ipv4/ip_default_ttl</filename>.</para>
 905
 906           <xi:include href="version-info.xml" xpointer="v234"/>
 907         </listitem>
 908       </varlistentry>
 909       <varlistentry>
 910         <term><varname>UDPChecksum=</varname></term>
 911         <listitem>
 912           <para>Takes a boolean. When true, specifies that UDP checksum is calculated for transmitted packets
 913           over IPv4.</para>
 914
 915           <xi:include href="version-info.xml" xpointer="v234"/>
 916         </listitem>
 917       </varlistentry>
 918       <varlistentry>
 919         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 920         <listitem>
 921           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 922
 923         <xi:include href="version-info.xml" xpointer="v234"/>
 924         </listitem>
 925       </varlistentry>
 926       <varlistentry>
 927         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 928         <listitem>
 929           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 930
 931         <xi:include href="version-info.xml" xpointer="v234"/>
 932         </listitem>
 933       </varlistentry>
 934       <varlistentry>
 935         <term><varname>DestinationPort=</varname></term>
 936         <listitem>
 937           <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 938           port of 6081 is used.</para>
 939
 940           <xi:include href="version-info.xml" xpointer="v234"/>
 941         </listitem>
 942       </varlistentry>
 943       <varlistentry>
 944         <term><varname>FlowLabel=</varname></term>
 945         <listitem>
 946           <para>Specifies the flow label to use in outgoing packets.</para>
 947
 948         <xi:include href="version-info.xml" xpointer="v234"/>
 949         </listitem>
 950       </varlistentry>
 951       <varlistentry>
 952         <term><varname>IPDoNotFragment=</varname></term>
 953         <listitem>
 954           <para>Accepts the same key as in [VXLAN] section.</para>
 955
 956         <xi:include href="version-info.xml" xpointer="v243"/>
 957         </listitem>
 958       </varlistentry>
 959       <varlistentry>
 960         <term><varname>InheritInnerProtocol=</varname></term>
 961         <listitem>
 962           <para>Takes a boolean. When true, inner Layer 3 protocol is set as Protocol Type in the GENEVE
 963           header instead of Ethernet. Defaults to false.</para>
 964
 965           <xi:include href="version-info.xml" xpointer="v254"/>
 966         </listitem>
 967       </varlistentry>
 968     </variablelist>
 969   </refsect1>
 970
 971   <refsect1>
 972     <title>[BareUDP] Section Options</title>
 973
 974     <para>The [BareUDP] section only applies for
 975     netdevs of kind <literal>bareudp</literal>, and accepts the
 976     following keys:</para>
 977
 978     <variablelist class='network-directives'>
 979       <varlistentry>
 980         <term><varname>DestinationPort=</varname></term>
 981         <listitem>
 982           <para>Specifies the destination UDP port (in range 1…65535). This is mandatory.</para>
 983
 984         <xi:include href="version-info.xml" xpointer="v247"/>
 985         </listitem>
 986       </varlistentry>
 987
 988       <varlistentry>
 989         <term><varname>EtherType=</varname></term>
 990         <listitem>
 991           <para>Specifies the L3 protocol. Takes one of <literal>ipv4</literal>, <literal>ipv6</literal>, <literal>mpls-uc</literal>
 992           or <literal>mpls-mc</literal>. This is mandatory.</para>
 993
 994         <xi:include href="version-info.xml" xpointer="v247"/>
 995         </listitem>
 996       </varlistentry>
 997     </variablelist>
 998   </refsect1>
 999
1000   <refsect1>
1001     <title>[L2TP] Section Options</title>
1002
1003     <para>The [L2TP] section only applies for
1004     netdevs of kind <literal>l2tp</literal>, and accepts the
1005     following keys:</para>
1006
1007     <variablelist class='network-directives'>
1008       <varlistentry>
1009         <term><varname>TunnelId=</varname></term>
1010         <listitem>
1011           <para>Specifies the tunnel identifier. Takes an number in the range 1…4294967295. The value used
1012           must match the <literal>PeerTunnelId=</literal> value being used at the peer. This setting is
1013           compulsory.</para>
1014
1015           <xi:include href="version-info.xml" xpointer="v242"/>
1016         </listitem>
1017       </varlistentry>
1018       <varlistentry>
1019         <term><varname>PeerTunnelId=</varname></term>
1020         <listitem>
1021           <para>Specifies the peer tunnel id. Takes a number in the range 1…4294967295. The value used must
1022           match the <literal>TunnelId=</literal> value being used at the peer. This setting is compulsory.
1023           </para>
1024
1025           <xi:include href="version-info.xml" xpointer="v242"/>
1026         </listitem>
1027       </varlistentry>
1028       <varlistentry>
1029         <term><varname>Remote=</varname></term>
1030         <listitem>
1031           <para>Specifies the IP address of the remote peer. This setting is compulsory.</para>
1032
1033         <xi:include href="version-info.xml" xpointer="v242"/>
1034         </listitem>
1035       </varlistentry>
1036       <varlistentry>
1037         <term><varname>Local=</varname></term>
1038         <listitem>
1039           <para>Specifies the IP address of a local interface. Takes an IP address, or the special
1040           values <literal>auto</literal>, <literal>static</literal>, or <literal>dynamic</literal>.
1041           Optionally a name of a local interface can be specified after <literal>@</literal>, e.g.
1042           <literal>192.168.0.1@eth0</literal> or <literal>auto@eth0</literal>. When an address is
1043           specified, then a local or specified interface must have the address, and the remote address
1044           must be accessible through the local address. If <literal>auto</literal>, then one of the
1045           addresses on a local or specified interface which is accessible to the remote address will be
1046           used. Similarly, if <literal>static</literal> or <literal>dynamic</literal> is set, then one
1047           of the static or dynamic addresses will be used. Defaults to <literal>auto</literal>.</para>
1048
1049           <xi:include href="version-info.xml" xpointer="v242"/>
1050         </listitem>
1051       </varlistentry>
1052       <varlistentry>
1053         <term><varname>EncapsulationType=</varname></term>
1054         <listitem>
1055           <para>Specifies the encapsulation type of the tunnel. Takes one of <literal>udp</literal> or
1056           <literal>ip</literal>.</para>
1057
1058         <xi:include href="version-info.xml" xpointer="v242"/>
1059         </listitem>
1060       </varlistentry>
1061       <varlistentry>
1062         <term><varname>UDPSourcePort=</varname></term>
1063         <listitem>
1064           <para>Specifies the UDP source port to be used for the tunnel. When UDP encapsulation is selected
1065           it's mandatory. Ignored when IP encapsulation is selected.</para>
1066
1067           <xi:include href="version-info.xml" xpointer="v242"/>
1068         </listitem>
1069       </varlistentry>
1070       <varlistentry>
1071         <term><varname>UDPDestinationPort=</varname></term>
1072         <listitem>
1073           <para>Specifies destination port. When UDP encapsulation is selected it's mandatory. Ignored when IP
1074           encapsulation is selected.</para>
1075
1076           <xi:include href="version-info.xml" xpointer="v245"/>
1077         </listitem>
1078       </varlistentry>
1079       <varlistentry>
1080         <term><varname>UDPChecksum=</varname></term>
1081         <listitem>
1082           <para>Takes a boolean. When true, specifies that UDP checksum is calculated for transmitted packets
1083           over IPv4.</para>
1084
1085           <xi:include href="version-info.xml" xpointer="v242"/>
1086         </listitem>
1087       </varlistentry>
1088       <varlistentry>
1089         <term><varname>UDP6ZeroChecksumTx=</varname></term>
1090         <listitem>
1091           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
1092
1093         <xi:include href="version-info.xml" xpointer="v242"/>
1094         </listitem>
1095       </varlistentry>
1096       <varlistentry>
1097         <term><varname>UDP6ZeroChecksumRx=</varname></term>
1098         <listitem>
1099           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
1100
1101         <xi:include href="version-info.xml" xpointer="v242"/>
1102         </listitem>
1103       </varlistentry>
1104     </variablelist>
1105   </refsect1>
1106
1107   <refsect1>
1108     <title>[L2TPSession] Section Options</title>
1109
1110     <para>The [L2TPSession] section only applies for
1111     netdevs of kind <literal>l2tp</literal>, and accepts the
1112     following keys:</para>
1113     <variablelist class='network-directives'>
1114       <varlistentry>
1115         <term><varname>Name=</varname></term>
1116         <listitem>
1117           <para>Specifies the name of the session. This setting is compulsory.</para>
1118
1119         <xi:include href="version-info.xml" xpointer="v242"/>
1120         </listitem>
1121       </varlistentry>
1122       <varlistentry>
1123         <term><varname>SessionId=</varname></term>
1124         <listitem>
1125           <para>Specifies the session identifier. Takes an number in the range 1…4294967295. The value used
1126           must match the <literal>SessionId=</literal> value being used at the peer. This setting is
1127           compulsory.</para>
1128
1129           <xi:include href="version-info.xml" xpointer="v242"/>
1130         </listitem>
1131       </varlistentry>
1132       <varlistentry>
1133         <term><varname>PeerSessionId=</varname></term>
1134         <listitem>
1135           <para>Specifies the peer session identifier. Takes an number in the range 1…4294967295.
1136           The value used must match the <literal>PeerSessionId=</literal> value being used at the peer.
1137           This setting is compulsory.</para>
1138
1139           <xi:include href="version-info.xml" xpointer="v242"/>
1140         </listitem>
1141       </varlistentry>
1142       <varlistentry>
1143         <term><varname>Layer2SpecificHeader=</varname></term>
1144         <listitem>
1145           <para>Specifies layer2specific header type of the session. One of <literal>none</literal> or <literal>default</literal>. Defaults to <literal>default</literal>.</para>
1146
1147         <xi:include href="version-info.xml" xpointer="v242"/>
1148         </listitem>
1149       </varlistentry>
1150     </variablelist>
1151   </refsect1>
1152
1153   <refsect1>
1154     <title>[MACsec] Section Options</title>
1155
1156     <para>The [MACsec] section only applies for network devices of kind
1157     <literal>macsec</literal>, and accepts the following keys:</para>
1158
1159     <variablelist class='network-directives'>
1160       <varlistentry>
1161         <term><varname>Port=</varname></term>
1162         <listitem>
1163           <para>Specifies the port to be used for the MACsec transmit channel. The port is used to make
1164           secure channel identifier (SCI). Takes a value between 1 and 65535. Defaults to unset.
1165           </para>
1166
1167           <xi:include href="version-info.xml" xpointer="v243"/>
1168         </listitem>
1169       </varlistentry>
1170       <varlistentry>
1171         <term><varname>Encrypt=</varname></term>
1172         <listitem>
1173           <para>Takes a boolean. When true, enable encryption. Defaults to unset.</para>
1174
1175         <xi:include href="version-info.xml" xpointer="v243"/>
1176         </listitem>
1177       </varlistentry>
1178     </variablelist>
1179   </refsect1>
1180
1181   <refsect1>
1182     <title>[MACsecReceiveChannel] Section Options</title>
1183     <para>The [MACsecReceiveChannel] section only applies for network devices of
1184     kind <literal>macsec</literal>, and accepts the following keys:</para>
1185
1186     <variablelist class='network-directives'>
1187       <varlistentry>
1188         <term><varname>Port=</varname></term>
1189         <listitem>
1190           <para>Specifies the port to be used for the MACsec receive channel. The port is used to make
1191           secure channel identifier (SCI). Takes a value between 1 and 65535. This option is
1192           compulsory, and is not set by default.</para>
1193
1194           <xi:include href="version-info.xml" xpointer="v243"/>
1195         </listitem>
1196       </varlistentry>
1197       <varlistentry>
1198         <term><varname>MACAddress=</varname></term>
1199         <listitem>
1200           <para>Specifies the MAC address to be used for the MACsec receive channel. The MAC address
1201           used to make secure channel identifier (SCI). This setting is compulsory, and is not set by
1202           default.</para>
1203
1204           <xi:include href="version-info.xml" xpointer="v243"/>
1205         </listitem>
1206       </varlistentry>
1207     </variablelist>
1208   </refsect1>
1209
1210   <refsect1>
1211     <title>[MACsecTransmitAssociation] Section Options</title>
1212
1213     <para>The [MACsecTransmitAssociation] section only applies for network devices
1214     of kind <literal>macsec</literal>, and accepts the following keys:</para>
1215
1216     <variablelist class='network-directives'>
1217       <varlistentry>
1218         <term><varname>PacketNumber=</varname></term>
1219         <listitem>
1220           <para>Specifies the packet number to be used for replay protection and the construction of
1221           the initialization vector (along with the secure channel identifier [SCI]). Takes a value
1222           between 1-4,294,967,295. Defaults to unset.
1223           </para>
1224
1225           <xi:include href="version-info.xml" xpointer="v243"/>
1226         </listitem>
1227       </varlistentry>
1228       <varlistentry>
1229         <term><varname>KeyId=</varname></term>
1230         <listitem>
1231           <para>Specifies the identification for the key. Takes a number between 0-255. This option
1232           is compulsory, and is not set by default.</para>
1233
1234           <xi:include href="version-info.xml" xpointer="v243"/>
1235         </listitem>
1236       </varlistentry>
1237       <varlistentry>
1238         <term><varname>Key=</varname></term>
1239         <listitem>
1240           <para>Specifies the encryption key used in the transmission channel. The same key must be
1241           configured on the peer’s matching receive channel. This setting is compulsory, and is not set
1242           by default. Takes a 128-bit key encoded in a hexadecimal string, for example
1243           <literal>dffafc8d7b9a43d5b9a3dfbbf6a30c16</literal>.</para>
1244
1245           <xi:include href="version-info.xml" xpointer="v243"/>
1246         </listitem>
1247       </varlistentry>
1248       <varlistentry>
1249         <term><varname>KeyFile=</varname></term>
1250         <listitem>
1251           <para>Takes an absolute path to a file which contains a 128-bit key encoded in a hexadecimal string,
1252           which will be used in the transmission channel. When this option is specified,
1253           <varname>Key=</varname> is ignored. Note that the file must be readable by the user
1254           <literal>systemd-network</literal>, so it should be, e.g., owned by
1255           <literal>root:systemd-network</literal> with a <literal>0640</literal> file mode. If the path
1256           refers to an <constant>AF_UNIX</constant> stream socket in the file system a connection is made to
1257           it and the key read from it.</para>
1258
1259           <xi:include href="version-info.xml" xpointer="v243"/>
1260         </listitem>
1261       </varlistentry>
1262       <varlistentry>
1263         <term><varname>Activate=</varname></term>
1264         <listitem>
1265           <para>Takes a boolean. If enabled, then the security association is activated. Defaults to
1266           unset.</para>
1267
1268           <xi:include href="version-info.xml" xpointer="v243"/>
1269         </listitem>
1270       </varlistentry>
1271       <varlistentry>
1272         <term><varname>UseForEncoding=</varname></term>
1273         <listitem>
1274           <para>Takes a boolean. If enabled, then the security association is used for encoding. Only
1275           one [MACsecTransmitAssociation] section can enable this option. When enabled,
1276           <varname>Activate=yes</varname> is implied. Defaults to unset.</para>
1277
1278           <xi:include href="version-info.xml" xpointer="v243"/>
1279         </listitem>
1280       </varlistentry>
1281     </variablelist>
1282   </refsect1>
1283
1284   <refsect1>
1285     <title>[MACsecReceiveAssociation] Section Options</title>
1286
1287     <para>The [MACsecReceiveAssociation] section only applies for
1288     network devices of kind <literal>macsec</literal>, and accepts the
1289     following keys:</para>
1290
1291     <variablelist class='network-directives'>
1292       <varlistentry>
1293         <term><varname>Port=</varname></term>
1294         <listitem>
1295           <para>Accepts the same key as in [MACsecReceiveChannel] section.</para>
1296
1297         <xi:include href="version-info.xml" xpointer="v243"/>
1298         </listitem>
1299       </varlistentry>
1300       <varlistentry>
1301         <term><varname>MACAddress=</varname></term>
1302         <listitem>
1303           <para>Accepts the same key as in [MACsecReceiveChannel] section.</para>
1304
1305         <xi:include href="version-info.xml" xpointer="v243"/>
1306         </listitem>
1307       </varlistentry>
1308       <varlistentry>
1309         <term><varname>PacketNumber=</varname></term>
1310         <listitem>
1311           <para>Accepts the same key as in [MACsecTransmitAssociation] section.</para>
1312
1313         <xi:include href="version-info.xml" xpointer="v243"/>
1314         </listitem>
1315       </varlistentry>
1316       <varlistentry>
1317         <term><varname>KeyId=</varname></term>
1318         <listitem>
1319           <para>Accepts the same key as in [MACsecTransmitAssociation] section.</para>
1320
1321         <xi:include href="version-info.xml" xpointer="v243"/>
1322         </listitem>
1323       </varlistentry>
1324       <varlistentry>
1325         <term><varname>Key=</varname></term>
1326         <listitem>
1327           <para>Accepts the same key as in [MACsecTransmitAssociation] section.</para>
1328
1329         <xi:include href="version-info.xml" xpointer="v243"/>
1330         </listitem>
1331       </varlistentry>
1332       <varlistentry>
1333         <term><varname>KeyFile=</varname></term>
1334         <listitem>
1335           <para>Accepts the same key as in [MACsecTransmitAssociation] section.</para>
1336
1337         <xi:include href="version-info.xml" xpointer="v243"/>
1338         </listitem>
1339       </varlistentry>
1340       <varlistentry>
1341         <term><varname>Activate=</varname></term>
1342         <listitem>
1343           <para>Accepts the same key as in [MACsecTransmitAssociation] section.</para>
1344
1345         <xi:include href="version-info.xml" xpointer="v243"/>
1346         </listitem>
1347       </varlistentry>
1348     </variablelist>
1349   </refsect1>
1350
1351   <refsect1>
1352     <title>[Tunnel] Section Options</title>
1353
1354     <para>The [Tunnel] section only applies for
1355     netdevs of kind
1356     <literal>ipip</literal>,
1357     <literal>sit</literal>,
1358     <literal>gre</literal>,
1359     <literal>gretap</literal>,
1360     <literal>ip6gre</literal>,
1361     <literal>ip6gretap</literal>,
1362     <literal>vti</literal>,
1363     <literal>vti6</literal>,
1364     <literal>ip6tnl</literal>, and
1365     <literal>erspan</literal> and accepts
1366     the following keys:</para>
1367
1368     <variablelist class='network-directives'>
1369       <varlistentry>
1370         <term><varname>External=</varname></term>
1371         <listitem>
1372           <para>Takes a boolean value. When true, then the tunnel is externally controlled, which is
1373           also known as collect metadata mode, and most settings below like <varname>Local=</varname>
1374           or <varname>Remote=</varname> are ignored. This implies <varname>Independent=</varname>.
1375           Defaults to false.</para>
1376
1377           <xi:include href="version-info.xml" xpointer="v251"/>
1378         </listitem>
1379       </varlistentry>
1380       <varlistentry>
1381         <term><varname>Local=</varname></term>
1382         <listitem>
1383           <para>A static local address for tunneled packets. It must be an address on another interface
1384           of this host, or one of the special values <literal>any</literal>,
1385           <literal>ipv4_link_local</literal>, <literal>ipv6_link_local</literal>,
1386           <literal>dhcp4</literal>, <literal>dhcp6</literal>, and <literal>slaac</literal>. If one
1387           of the special values except for <literal>any</literal> is specified, an address which
1388           matches the corresponding type on the underlying interface will be used. Defaults to
1389           <literal>any</literal>.</para>
1390
1391           <xi:include href="version-info.xml" xpointer="v215"/>
1392         </listitem>
1393       </varlistentry>
1394       <varlistentry>
1395         <term><varname>Remote=</varname></term>
1396         <listitem>
1397           <para>The remote endpoint of the tunnel. Takes an IP address or the special value
1398           <literal>any</literal>.</para>
1399
1400           <xi:include href="version-info.xml" xpointer="v215"/>
1401         </listitem>
1402       </varlistentry>
1403       <varlistentry>
1404         <term><varname>TOS=</varname></term>
1405         <listitem>
1406           <para>The Type Of Service byte value for a tunnel interface.
1407           For details about the TOS, see the
1408           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
1409           Service in the Internet Protocol Suite </ulink> document.
1410           </para>
1411
1412           <xi:include href="version-info.xml" xpointer="v215"/>
1413         </listitem>
1414       </varlistentry>
1415       <varlistentry>
1416         <term><varname>TTL=</varname></term>
1417         <listitem>
1418           <para>A fixed Time To Live N on tunneled packets. N is a
1419           number in the range 1…255. 0 is a special value meaning that
1420           packets inherit the TTL value. The default value for IPv4
1421           tunnels is 0 (inherit). The default value for IPv6 tunnels is
1422           64.</para>
1423
1424           <xi:include href="version-info.xml" xpointer="v215"/>
1425         </listitem>
1426       </varlistentry>
1427       <varlistentry>
1428         <term><varname>DiscoverPathMTU=</varname></term>
1429         <listitem>
1430           <para>Takes a boolean. When true, enables Path MTU Discovery on
1431           the tunnel.
1432           When <varname>IgnoreDontFragment=</varname> is enabled,
1433           defaults to false. Otherwise, defaults to true.</para>
1434
1435           <xi:include href="version-info.xml" xpointer="v215"/>
1436         </listitem>
1437       </varlistentry>
1438       <varlistentry>
1439         <term><varname>IgnoreDontFragment=</varname></term>
1440         <listitem>
1441           <para>Takes a boolean. When true, enables IPv4 Don't Fragment (DF) suppression on
1442           the tunnel. Defaults to false.
1443           Note that if <varname>IgnoreDontFragment=</varname> is set to true,
1444           <varname>DiscoverPathMTU=</varname> cannot be set to true.
1445           Only applicable to GRE, GRETAP, and ERSPAN tunnels.</para>
1446
1447           <xi:include href="version-info.xml" xpointer="v254"/>
1448         </listitem>
1449       </varlistentry>
1450       <varlistentry>
1451         <term><varname>IPv6FlowLabel=</varname></term>
1452         <listitem>
1453           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
1454           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
1455           RFC 2460</ulink>), which is used by a node to label packets of a flow.
1456           It is only used for IPv6 tunnels.
1457           A flow label of zero is used to indicate packets that have
1458           not been labeled.
1459           It can be configured to a value in the range 0…0xFFFFF, or be
1460           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
1461
1462         <xi:include href="version-info.xml" xpointer="v223"/>
1463         </listitem>
1464       </varlistentry>
1465       <varlistentry>
1466         <term><varname>CopyDSCP=</varname></term>
1467         <listitem>
1468           <para>Takes a boolean. When true, the Differentiated Service Code
1469           Point (DSCP) field will be copied to the inner header from
1470           outer header during the decapsulation of an IPv6 tunnel
1471           packet. DSCP is a field in an IP packet that enables different
1472           levels of service to be assigned to network traffic.
1473           Defaults to <literal>no</literal>.
1474           </para>
1475
1476           <xi:include href="version-info.xml" xpointer="v223"/>
1477         </listitem>
1478       </varlistentry>
1479       <varlistentry>
1480         <term><varname>EncapsulationLimit=</varname></term>
1481         <listitem>
1482           <para>The Tunnel Encapsulation Limit option specifies how many additional
1483           levels of encapsulation are permitted to be prepended to the packet.
1484           For example, a Tunnel Encapsulation Limit option containing a limit
1485           value of zero means that a packet carrying that option may not enter
1486           another tunnel before exiting the current tunnel.
1487           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
1488           The valid range is 0…255 and <literal>none</literal>. Defaults to 4.
1489         </para>
1490
1491           <xi:include href="version-info.xml" xpointer="v226"/>
1492         </listitem>
1493       </varlistentry>
1494       <varlistentry>
1495         <term><varname>Key=</varname></term>
1496         <listitem>
1497           <para>The <varname>Key=</varname> parameter specifies the same key to use in
1498           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
1499           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
1500           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
1501           and control path) in IP XFRM (framework used to implement IPsec protocol).
1502           See <ulink url="https://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
1503           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6,
1504           GRE, GRETAP, and ERSPAN tunnels.</para>
1505
1506         <xi:include href="version-info.xml" xpointer="v231"/>
1507         </listitem>
1508       </varlistentry>
1509       <varlistentry>
1510         <term><varname>InputKey=</varname></term>
1511         <listitem>
1512           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
1513           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1514           and ERSPAN tunnels.</para>
1515
1516         <xi:include href="version-info.xml" xpointer="v231"/>
1517         </listitem>
1518       </varlistentry>
1519       <varlistentry>
1520         <term><varname>OutputKey=</varname></term>
1521         <listitem>
1522           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
1523           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1524           and ERSPAN tunnels.</para>
1525
1526         <xi:include href="version-info.xml" xpointer="v231"/>
1527         </listitem>
1528       </varlistentry>
1529       <varlistentry>
1530         <term><varname>Mode=</varname></term>
1531         <listitem>
1532           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
1533           modes
1534           <literal>ip6ip6</literal> for IPv6 over IPv6,
1535           <literal>ipip6</literal> for IPv4 over IPv6 or
1536           <literal>any</literal> for either.
1537           </para>
1538
1539         <xi:include href="version-info.xml" xpointer="v219"/>
1540         </listitem>
1541       </varlistentry>
1542       <varlistentry>
1543         <term><varname>Independent=</varname></term>
1544         <listitem>
1545           <para>Takes a boolean. When false (the default), the tunnel is always created over some network
1546           device, and a .network file that requests this tunnel using <varname>Tunnel=</varname> is required
1547           for the tunnel to be created. When true, the tunnel is created independently of any network as
1548           "tunnel@NONE".</para>
1549
1550           <xi:include href="version-info.xml" xpointer="v235"/>
1551         </listitem>
1552       </varlistentry>
1553       <varlistentry>
1554         <term><varname>AssignToLoopback=</varname></term>
1555         <listitem>
1556           <para>Takes a boolean. If set to <literal>yes</literal>, the loopback interface <literal>lo</literal>
1557           is used as the underlying device of the tunnel interface. Defaults to <literal>no</literal>.</para>
1558
1559         <xi:include href="version-info.xml" xpointer="v243"/>
1560         </listitem>
1561       </varlistentry>
1562       <varlistentry>
1563         <term><varname>AllowLocalRemote=</varname></term>
1564         <listitem>
1565           <para>Takes a boolean. When true allows tunnel traffic on <varname>ip6tnl</varname> devices where the remote endpoint is a local host address.
1566           When unset, the kernel's default will be used.
1567           </para>
1568
1569         <xi:include href="version-info.xml" xpointer="v237"/>
1570         </listitem>
1571       </varlistentry>
1572       <varlistentry>
1573         <term><varname>FooOverUDP=</varname></term>
1574         <listitem>
1575           <para>Takes a boolean. Specifies whether <varname>FooOverUDP=</varname> tunnel is to be configured.
1576           Defaults to false. This takes effects only for IPIP, SIT, GRE, and GRETAP tunnels.
1577           For more detail information see
1578           <ulink url="https://lwn.net/Articles/614348">Foo over UDP</ulink></para>
1579
1580         <xi:include href="version-info.xml" xpointer="v240"/>
1581         </listitem>
1582       </varlistentry>
1583       <varlistentry>
1584         <term><varname>FOUDestinationPort=</varname></term>
1585         <listitem>
1586           <para>This setting specifies the UDP destination port for encapsulation.
1587           This field is mandatory when <varname>FooOverUDP=yes</varname>, and is not set by default.</para>
1588
1589           <xi:include href="version-info.xml" xpointer="v240"/>
1590         </listitem>
1591       </varlistentry>
1592       <varlistentry>
1593         <term><varname>FOUSourcePort=</varname></term>
1594         <listitem>
1595           <para>This setting specifies the UDP source port for encapsulation. Defaults to <constant>0</constant>
1596           — that is, the source port for packets is left to the network stack to decide.</para>
1597
1598         <xi:include href="version-info.xml" xpointer="v240"/>
1599         </listitem>
1600       </varlistentry>
1601       <varlistentry>
1602         <term><varname>Encapsulation=</varname></term>
1603         <listitem>
1604           <para>Accepts the same key as in the [FooOverUDP] section.</para>
1605
1606         <xi:include href="version-info.xml" xpointer="v240"/>
1607         </listitem>
1608       </varlistentry>
1609       <varlistentry>
1610         <term><varname>IPv6RapidDeploymentPrefix=</varname></term>
1611         <listitem>
1612           <para>Reconfigure the tunnel for <ulink url="https://tools.ietf.org/html/rfc5569">IPv6 Rapid
1613           Deployment</ulink>, also known as 6rd. The value is an ISP-specific IPv6 prefix with a non-zero length. Only
1614           applicable to SIT tunnels.</para>
1615
1616         <xi:include href="version-info.xml" xpointer="v240"/>
1617         </listitem>
1618       </varlistentry>
1619       <varlistentry>
1620         <term><varname>ISATAP=</varname></term>
1621         <listitem>
1622           <para>Takes a boolean. If set, configures the tunnel as Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) tunnel.
1623           Only applicable to SIT tunnels. When unset, the kernel's default will be used.</para>
1624
1625           <xi:include href="version-info.xml" xpointer="v240"/>
1626         </listitem>
1627       </varlistentry>
1628       <varlistentry>
1629         <term><varname>SerializeTunneledPackets=</varname></term>
1630         <listitem>
1631           <para>Takes a boolean. If set to yes, then packets are serialized. Only applies for GRE,
1632           GRETAP, and ERSPAN tunnels. When unset, the kernel's default will be used.
1633           </para>
1634
1635           <xi:include href="version-info.xml" xpointer="v240"/>
1636         </listitem>
1637       </varlistentry>
1638       <varlistentry>
1639         <term><varname>ERSPANVersion=</varname></term>
1640         <listitem>
1641           <para>Specifies the ERSPAN version number. Takes 0 for version 0 (a.k.a. type I), 1 for version 1
1642           (a.k.a. type II), or 2 for version 2 (a.k.a. type III). Defaults to 1.</para>
1643
1644           <xi:include href="version-info.xml" xpointer="v252"/>
1645         </listitem>
1646       </varlistentry>
1647       <varlistentry>
1648         <term><varname>ERSPANIndex=</varname></term>
1649         <listitem>
1650           <para>Specifies the ERSPAN v1 index field for the interface. Takes an integer in the range
1651           0…1048575, which is associated with the ERSPAN traffic's source port and direction. Only used when
1652           <varname>ERSPANVersion=1</varname>. Defaults to 0.</para>
1653
1654           <xi:include href="version-info.xml" xpointer="v240"/>
1655         </listitem>
1656       </varlistentry>
1657       <varlistentry>
1658         <term><varname>ERSPANDirection=</varname></term>
1659         <listitem>
1660           <para>Specifies the ERSPAN v2 mirrored traffic's direction. Takes <literal>ingress</literal> or
1661           <literal>egress</literal>. Only used when <varname>ERSPANVersion=2</varname>. Defaults to
1662           <literal>ingress</literal>.</para>
1663
1664         <xi:include href="version-info.xml" xpointer="v252"/>
1665         </listitem>
1666       </varlistentry>
1667       <varlistentry>
1668         <term><varname>ERSPANHardwareId=</varname></term>
1669         <listitem>
1670           <para>Specifies an unique identifier of the ERSPAN v2 engine. Takes an integer in the range 0…63.
1671           Only used when <varname>ERSPANVersion=2</varname>. Defaults to 0.</para>
1672
1673           <xi:include href="version-info.xml" xpointer="v252"/>
1674         </listitem>
1675       </varlistentry>
1676     </variablelist>
1677   </refsect1>
1678
1679   <refsect1>
1680     <title>[FooOverUDP] Section Options</title>
1681
1682     <para>The [FooOverUDP] section only applies for
1683     netdevs of kind <literal>fou</literal> and accepts the
1684     following keys:</para>
1685
1686     <variablelist class='network-directives'>
1687       <varlistentry>
1688         <term><varname>Encapsulation=</varname></term>
1689         <listitem>
1690           <para>Specifies the encapsulation mechanism used to store networking packets of various protocols
1691           inside the UDP packets. Supports the following values:
1692
1693           <literal>FooOverUDP</literal> provides the simplest no-frills model of UDP encapsulation, it simply
1694           encapsulates packets directly in the UDP payload. <literal>GenericUDPEncapsulation</literal> is a
1695           generic and extensible encapsulation, it allows encapsulation of packets for any IP protocol and
1696           optional data as part of the encapsulation. For more detailed information see <ulink
1697           url="https://lwn.net/Articles/615044">Generic UDP Encapsulation</ulink>. Defaults to
1698           <literal>FooOverUDP</literal>.
1699           </para>
1700
1701           <xi:include href="version-info.xml" xpointer="v240"/>
1702         </listitem>
1703       </varlistentry>
1704       <varlistentry>
1705         <term><varname>Port=</varname></term>
1706         <listitem>
1707           <para>Specifies the port number where the encapsulated packets will arrive. Those packets will be
1708           removed and manually fed back into the network stack with the encapsulation removed to be sent to
1709           the real destination. This option is mandatory.</para>
1710
1711           <xi:include href="version-info.xml" xpointer="v240"/>
1712         </listitem>
1713       </varlistentry>
1714       <varlistentry>
1715         <term><varname>PeerPort=</varname></term>
1716         <listitem>
1717           <para>Specifies the peer port number. Defaults to unset. Note that when peer port is set
1718           <literal>Peer=</literal> address is mandatory.</para>
1719
1720           <xi:include href="version-info.xml" xpointer="v243"/>
1721         </listitem>
1722       </varlistentry>
1723       <varlistentry>
1724         <term><varname>Protocol=</varname></term>
1725         <listitem>
1726           <para>The <varname>Protocol=</varname> specifies the protocol number of the packets arriving
1727           at the UDP port. When <varname>Encapsulation=FooOverUDP</varname>, this field is mandatory
1728           and is not set by default. Takes an IP protocol name such as <literal>gre</literal> or
1729           <literal>ipip</literal>, or an integer within the range 1…255. When
1730           <varname>Encapsulation=GenericUDPEncapsulation</varname>, this must not be specified.</para>
1731
1732         <xi:include href="version-info.xml" xpointer="v240"/>
1733         </listitem>
1734       </varlistentry>
1735       <varlistentry>
1736         <term><varname>Peer=</varname></term>
1737         <listitem>
1738           <para>Configures peer IP address. Note that when peer address is set <literal>PeerPort=</literal>
1739           is mandatory.</para>
1740
1741         <xi:include href="version-info.xml" xpointer="v243"/>
1742         </listitem>
1743       </varlistentry>
1744       <varlistentry>
1745         <term><varname>Local=</varname></term>
1746         <listitem>
1747           <para>Configures local IP address.</para>
1748
1749         <xi:include href="version-info.xml" xpointer="v243"/>
1750         </listitem>
1751       </varlistentry>
1752     </variablelist>
1753   </refsect1>
1754
1755   <refsect1>
1756     <title>[Peer] Section Options</title>
1757
1758     <para>The [Peer] section only applies for
1759     netdevs of kind <literal>veth</literal> and accepts the
1760     following keys:</para>
1761
1762     <variablelist class='network-directives'>
1763       <varlistentry>
1764         <term><varname>Name=</varname></term>
1765         <listitem>
1766           <para>The interface name used when creating the netdev.
1767           This setting is compulsory.</para>
1768
1769           <xi:include href="version-info.xml" xpointer="v215"/>
1770         </listitem>
1771       </varlistentry>
1772       <varlistentry>
1773         <term><varname>MACAddress=</varname></term>
1774         <listitem>
1775           <para>The peer MACAddress, if not set, it is generated in
1776           the same way as the MAC address of the main
1777           interface.</para>
1778
1779           <xi:include href="version-info.xml" xpointer="v215"/>
1780         </listitem>
1781       </varlistentry>
1782     </variablelist>
1783   </refsect1>
1784
1785   <refsect1>
1786     <title>[VXCAN] Section Options</title>
1787
1788     <para>The [VXCAN] section only applies for
1789     netdevs of kind <literal>vxcan</literal> and accepts the
1790     following key:</para>
1791
1792     <variablelist class='network-directives'>
1793       <varlistentry>
1794         <term><varname>Peer=</varname></term>
1795         <listitem>
1796           <para>The peer interface name used when creating the netdev.
1797           This setting is compulsory.</para>
1798
1799           <xi:include href="version-info.xml" xpointer="v236"/>
1800         </listitem>
1801       </varlistentry>
1802     </variablelist>
1803   </refsect1>
1804
1805   <refsect1>
1806     <title>[Tun] Section Options</title>
1807
1808     <para>The [Tun] section only applies for
1809     netdevs of kind <literal>tun</literal>, and accepts the following
1810     keys:</para>
1811
1812     <variablelist class='network-directives'>
1813       <varlistentry>
1814         <term><varname>MultiQueue=</varname></term>
1815         <listitem><para>Takes a boolean. Configures whether
1816         to use multiple file descriptors (queues) to parallelize
1817         packets sending and receiving. Defaults to
1818         <literal>no</literal>.</para>
1819
1820         <xi:include href="version-info.xml" xpointer="v215"/>
1821         </listitem>
1822       </varlistentry>
1823       <varlistentry>
1824         <term><varname>PacketInfo=</varname></term>
1825         <listitem><para>Takes a boolean. Configures whether
1826         packets should be prepended with four extra bytes (two flag
1827         bytes and two protocol bytes). If disabled, it indicates that
1828         the packets will be pure IP packets. Defaults to
1829         <literal>no</literal>.</para>
1830
1831         <xi:include href="version-info.xml" xpointer="v215"/>
1832         </listitem>
1833       </varlistentry>
1834       <varlistentry>
1835         <term><varname>VNetHeader=</varname></term>
1836         <listitem><para>Takes a boolean. Configures
1837         IFF_VNET_HDR flag for a tun or tap device. It allows sending
1838         and receiving larger Generic Segmentation Offload (GSO)
1839         packets. This may increase throughput significantly.
1840         Defaults to
1841         <literal>no</literal>.</para>
1842
1843         <xi:include href="version-info.xml" xpointer="v223"/>
1844         </listitem>
1845       </varlistentry>
1846       <varlistentry>
1847         <term><varname>User=</varname></term>
1848         <listitem><para>User to grant access to the
1849         <filename>/dev/net/tun</filename> device.</para>
1850
1851         <xi:include href="version-info.xml" xpointer="v215"/>
1852         </listitem>
1853       </varlistentry>
1854       <varlistentry>
1855         <term><varname>Group=</varname></term>
1856         <listitem><para>Group to grant access to the
1857         <filename>/dev/net/tun</filename> device.</para>
1858
1859         <xi:include href="version-info.xml" xpointer="v215"/>
1860         </listitem>
1861       </varlistentry>
1862       <varlistentry>
1863         <term><varname>KeepCarrier=</varname></term>
1864         <listitem>
1865           <para>Takes a boolean. If enabled, to make the interface maintain its carrier status, the file
1866           descriptor of the interface is kept open. This may be useful to keep the interface in running
1867           state, for example while the backing process is temporarily shutdown. Defaults to
1868           <literal>no</literal>.</para>
1869
1870           <xi:include href="version-info.xml" xpointer="v252"/>
1871         </listitem>
1872       </varlistentry>
1873     </variablelist>
1874   </refsect1>
1875
1876   <refsect1>
1877     <title>[Tap] Section Options</title>
1878
1879     <para>The [Tap] section only applies for
1880     netdevs of kind <literal>tap</literal>, and accepts the same keys
1881     as the [Tun] section.</para>
1882   </refsect1>
1883
1884   <refsect1>
1885     <title>[WireGuard] Section Options</title>
1886
1887     <para>The [WireGuard] section accepts the following
1888     keys:</para>
1889
1890     <variablelist class='network-directives'>
1891       <varlistentry>
1892         <term><varname>PrivateKey=</varname></term>
1893         <listitem>
1894           <para>The Base64 encoded private key for the interface. It can be
1895           generated using the <command>wg genkey</command> command
1896           (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1897           This option or <varname>PrivateKeyFile=</varname> is mandatory to use WireGuard.
1898           Note that because this information is secret, you may want to set
1899           the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1900           with a <literal>0640</literal> file mode.</para>
1901
1902           <xi:include href="version-info.xml" xpointer="v237"/>
1903         </listitem>
1904       </varlistentry>
1905       <varlistentry>
1906         <term><varname>PrivateKeyFile=</varname></term>
1907         <listitem>
1908           <para>Takes an absolute path to a file which contains the Base64 encoded private key for the
1909           interface.  When this option is specified, then <varname>PrivateKey=</varname> is ignored.  Note
1910           that the file must be readable by the user <literal>systemd-network</literal>, so it should be,
1911           e.g., owned by <literal>root:systemd-network</literal> with a <literal>0640</literal> file mode. If
1912           the path refers to an <constant>AF_UNIX</constant> stream socket in the file system a connection is
1913           made to it and the key read from it.</para>
1914
1915           <xi:include href="version-info.xml" xpointer="v242"/>
1916         </listitem>
1917       </varlistentry>
1918       <varlistentry>
1919         <term><varname>ListenPort=</varname></term>
1920         <listitem>
1921           <para>Sets UDP port for listening. Takes either value between 1 and 65535
1922           or <literal>auto</literal>. If <literal>auto</literal> is specified,
1923           the port is automatically generated based on interface name.
1924           Defaults to <literal>auto</literal>.</para>
1925
1926           <xi:include href="version-info.xml" xpointer="v237"/>
1927         </listitem>
1928       </varlistentry>
1929       <varlistentry>
1930         <term><varname>FirewallMark=</varname></term>
1931         <listitem>
1932           <para>Sets a firewall mark on outgoing WireGuard packets from this interface. Takes a number between 1 and 4294967295.</para>
1933
1934         <xi:include href="version-info.xml" xpointer="v243"/>
1935         </listitem>
1936       </varlistentry>
1937       <varlistentry>
1938         <term><varname>RouteTable=</varname></term>
1939         <listitem>
1940           <para>The table identifier for the routes to the addresses specified in the
1941           <varname>AllowedIPs=</varname>. Takes a negative boolean value, one of the predefined names
1942           <literal>default</literal>, <literal>main</literal>, and <literal>local</literal>, names
1943           defined in <varname>RouteTable=</varname> in
1944           <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1945           or a number in the range 1…4294967295. When <literal>off</literal> the routes to the
1946           addresses specified in the <varname>AllowedIPs=</varname> setting will not be configured.
1947           Defaults to false. This setting will be ignored when the same setting is specified in the
1948           [WireGuardPeer] section.</para>
1949
1950           <xi:include href="version-info.xml" xpointer="v250"/>
1951         </listitem>
1952       </varlistentry>
1953       <varlistentry>
1954         <term><varname>RouteMetric=</varname></term>
1955         <listitem>
1956           <para>The priority of the routes to the addresses specified in the
1957           <varname>AllowedIPs=</varname>. Takes an integer in the range 0…4294967295. Defaults to 0
1958           for IPv4 addresses, and 1024 for IPv6 addresses. This setting will be ignored when the same
1959           setting is specified in the [WireGuardPeer] section.</para>
1960
1961           <xi:include href="version-info.xml" xpointer="v250"/>
1962         </listitem>
1963       </varlistentry>
1964     </variablelist>
1965   </refsect1>
1966
1967   <refsect1>
1968     <title>[WireGuardPeer] Section Options</title>
1969
1970     <para>The [WireGuardPeer] section accepts the following
1971     keys:</para>
1972
1973     <variablelist class='network-directives'>
1974       <varlistentry>
1975         <term><varname>PublicKey=</varname></term>
1976         <listitem>
1977           <para>Sets a Base64 encoded public key calculated by <command>wg pubkey</command>
1978           (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1979           from a private key, and usually transmitted out of band to the
1980           author of the configuration file. This option is mandatory for this
1981           section.</para>
1982
1983         <xi:include href="version-info.xml" xpointer="v237"/>
1984         </listitem>
1985       </varlistentry>
1986       <varlistentry>
1987         <term><varname>PresharedKey=</varname></term>
1988         <listitem>
1989           <para>Optional preshared key for the interface. It can be generated
1990           by the <command>wg genpsk</command> command. This option adds an
1991           additional layer of symmetric-key cryptography to be mixed into the
1992           already existing public-key cryptography, for post-quantum
1993           resistance.
1994           Note that because this information is secret, you may want to set
1995           the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1996           with a <literal>0640</literal> file mode.</para>
1997
1998           <xi:include href="version-info.xml" xpointer="v237"/>
1999         </listitem>
2000       </varlistentry>
2001       <varlistentry>
2002         <term><varname>PresharedKeyFile=</varname></term>
2003         <listitem>
2004           <para>Takes an absolute path to a file which contains the Base64 encoded preshared key for the
2005           peer. When this option is specified, then <varname>PresharedKey=</varname> is ignored.  Note that
2006           the file must be readable by the user <literal>systemd-network</literal>, so it should be, e.g.,
2007           owned by <literal>root:systemd-network</literal> with a <literal>0640</literal> file mode. If the
2008           path refers to an <constant>AF_UNIX</constant> stream socket in the file system a connection is
2009           made to it and the key read from it.</para>
2010
2011           <xi:include href="version-info.xml" xpointer="v242"/>
2012         </listitem>
2013       </varlistentry>
2014       <varlistentry>
2015         <term><varname>AllowedIPs=</varname></term>
2016         <listitem>
2017           <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks from which this peer
2018           is allowed to send incoming traffic and to which outgoing traffic for this peer is directed. This
2019           setting can be specified multiple times. If an empty string is assigned, then the all previous
2020           assignments are cleared.</para>
2021
2022           <para>The catch-all 0.0.0.0/0 may be specified for matching all IPv4 addresses,
2023           and ::/0 may be specified for matching all IPv6 addresses.</para>
2024
2025           <para>Note that this only affects <emphasis>routing inside the network interface itself</emphasis>,
2026           i.e. the packets that pass through the tunnel itself. To cause packets to be sent via the tunnel in
2027           the first place, an appropriate route needs to be added as well — either in the
2028           <literal>[Routes]</literal> section on the <literal>.network</literal> matching the wireguard
2029           interface, or externally to <filename>systemd-networkd</filename>.</para>
2030
2031           <xi:include href="version-info.xml" xpointer="v237"/>
2032         </listitem>
2033       </varlistentry>
2034       <varlistentry>
2035         <term><varname>Endpoint=</varname></term>
2036         <listitem>
2037           <para>Sets an endpoint IP address or hostname, followed by a colon, and then
2038           a port number. IPv6 address must be in the square brackets. For example,
2039           <literal>111.222.333.444:51820</literal> for IPv4 and <literal>[1111:2222::3333]:51820</literal>
2040           for IPv6 address. This endpoint will be updated automatically once to
2041           the most recent source IP address and port of correctly
2042           authenticated packets from the peer at configuration time.</para>
2043
2044           <xi:include href="version-info.xml" xpointer="v237"/>
2045         </listitem>
2046       </varlistentry>
2047       <varlistentry>
2048         <term><varname>PersistentKeepalive=</varname></term>
2049         <listitem>
2050           <para>Sets a seconds interval, between 1 and 65535 inclusive, of how often
2051           to send an authenticated empty packet to the peer for the purpose
2052           of keeping a stateful firewall or NAT mapping valid persistently.
2053           For example, if the interface very rarely sends traffic, but it
2054           might at anytime receive traffic from a peer, and it is behind NAT,
2055           the interface might benefit from having a persistent keepalive
2056           interval of 25 seconds. If set to 0 or "off", this option is
2057           disabled. By default or when unspecified, this option is off.
2058           Most users will not need this.</para>
2059
2060           <xi:include href="version-info.xml" xpointer="v237"/>
2061         </listitem>
2062       </varlistentry>
2063       <varlistentry>
2064         <term><varname>RouteTable=</varname></term>
2065         <listitem>
2066           <para>The table identifier for the routes to the addresses specified in the
2067           <varname>AllowedIPs=</varname>. Takes a negative boolean value, one of the predefined names
2068           <literal>default</literal>, <literal>main</literal>, and <literal>local</literal>, names
2069           defined in <varname>RouteTable=</varname> in
2070           <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
2071           or a number in the range 1…4294967295. Defaults to unset, and the value specified in the
2072           same setting in the [WireGuard] section will be used.</para>
2073
2074           <xi:include href="version-info.xml" xpointer="v250"/>
2075         </listitem>
2076       </varlistentry>
2077       <varlistentry>
2078         <term><varname>RouteMetric=</varname></term>
2079         <listitem>
2080           <para>The priority of the routes to the addresses specified in the
2081           <varname>AllowedIPs=</varname>. Takes an integer in the range 0…4294967295. Defaults to
2082           unset, and the value specified in the same setting in the [WireGuard] section will be used.
2083           </para>
2084
2085           <xi:include href="version-info.xml" xpointer="v250"/>
2086         </listitem>
2087       </varlistentry>
2088     </variablelist>
2089   </refsect1>
2090
2091   <refsect1>
2092     <title>[Bond] Section Options</title>
2093
2094     <para>The [Bond] section accepts the following
2095     key:</para>
2096
2097     <variablelist class='network-directives'>
2098       <varlistentry>
2099         <term><varname>Mode=</varname></term>
2100         <listitem>
2101           <para>Specifies one of the bonding policies. The default is
2102           <literal>balance-rr</literal> (round robin). Possible values are
2103           <literal>balance-rr</literal>,
2104           <literal>active-backup</literal>,
2105           <literal>balance-xor</literal>,
2106           <literal>broadcast</literal>,
2107           <literal>802.3ad</literal>,
2108           <literal>balance-tlb</literal>, and
2109           <literal>balance-alb</literal>.
2110           </para>
2111
2112           <xi:include href="version-info.xml" xpointer="v216"/>
2113         </listitem>
2114       </varlistentry>
2115
2116       <varlistentry>
2117         <term><varname>TransmitHashPolicy=</varname></term>
2118         <listitem>
2119           <para>Selects the transmit hash policy to use for slave
2120           selection in balance-xor, 802.3ad, and tlb modes. Possible
2121           values are
2122           <literal>layer2</literal>,
2123           <literal>layer3+4</literal>,
2124           <literal>layer2+3</literal>,
2125           <literal>encap2+3</literal>, and
2126           <literal>encap3+4</literal>.
2127           </para>
2128
2129           <xi:include href="version-info.xml" xpointer="v216"/>
2130         </listitem>
2131       </varlistentry>
2132
2133       <varlistentry>
2134         <term><varname>LACPTransmitRate=</varname></term>
2135         <listitem>
2136           <para>Specifies the rate with which link partner transmits
2137           Link Aggregation Control Protocol Data Unit packets in
2138           802.3ad mode. Possible values are <literal>slow</literal>,
2139           which requests partner to transmit LACPDUs every 30 seconds,
2140           and <literal>fast</literal>, which requests partner to
2141           transmit LACPDUs every second. The default value is
2142           <literal>slow</literal>.</para>
2143
2144           <xi:include href="version-info.xml" xpointer="v216"/>
2145         </listitem>
2146       </varlistentry>
2147
2148       <varlistentry>
2149         <term><varname>MIIMonitorSec=</varname></term>
2150         <listitem>
2151           <para>Specifies the frequency that Media Independent
2152           Interface link monitoring will occur. A value of zero
2153           disables MII link monitoring. This value is rounded down to
2154           the nearest millisecond. The default value is 0.</para>
2155
2156           <xi:include href="version-info.xml" xpointer="v216"/>
2157         </listitem>
2158       </varlistentry>
2159
2160       <varlistentry>
2161         <term><varname>UpDelaySec=</varname></term>
2162         <listitem>
2163           <para>Specifies the delay before a link is enabled after a
2164           link up status has been detected. This value is rounded down
2165           to a multiple of <varname>MIIMonitorSec=</varname>. The default value is
2166           0.</para>
2167
2168           <xi:include href="version-info.xml" xpointer="v216"/>
2169         </listitem>
2170       </varlistentry>
2171
2172       <varlistentry>
2173         <term><varname>DownDelaySec=</varname></term>
2174         <listitem>
2175           <para>Specifies the delay before a link is disabled after a
2176           link down status has been detected. This value is rounded
2177           down to a multiple of <varname>MIIMonitorSec=</varname>. The default value is
2178           0.</para>
2179
2180           <xi:include href="version-info.xml" xpointer="v216"/>
2181         </listitem>
2182       </varlistentry>
2183
2184       <varlistentry>
2185         <term><varname>LearnPacketIntervalSec=</varname></term>
2186         <listitem>
2187           <para>Specifies the number of seconds between instances where the bonding
2188           driver sends learning packets to each slave peer switch.
2189           The valid range is 1…0x7fffffff; the default value is 1. This option
2190           has an effect only for the balance-tlb and balance-alb modes.</para>
2191
2192           <xi:include href="version-info.xml" xpointer="v220"/>
2193         </listitem>
2194       </varlistentry>
2195
2196       <varlistentry>
2197         <term><varname>AdSelect=</varname></term>
2198         <listitem>
2199           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
2200           <literal>stable</literal>,
2201           <literal>bandwidth</literal> and
2202           <literal>count</literal>.
2203           </para>
2204
2205           <xi:include href="version-info.xml" xpointer="v220"/>
2206         </listitem>
2207       </varlistentry>
2208
2209       <varlistentry>
2210         <term><varname>AdActorSystemPriority=</varname></term>
2211         <listitem>
2212           <para>Specifies the 802.3ad actor system priority. Takes a number in the range 1…65535.</para>
2213
2214         <xi:include href="version-info.xml" xpointer="v240"/>
2215         </listitem>
2216       </varlistentry>
2217
2218       <varlistentry>
2219         <term><varname>AdUserPortKey=</varname></term>
2220         <listitem>
2221           <para>Specifies the 802.3ad user defined portion of the port key. Takes a number in the range
2222           0…1023.</para>
2223
2224           <xi:include href="version-info.xml" xpointer="v240"/>
2225         </listitem>
2226       </varlistentry>
2227
2228       <varlistentry>
2229         <term><varname>AdActorSystem=</varname></term>
2230         <listitem>
2231           <para>Specifies the 802.3ad system MAC address. This cannot be a null or multicast address.
2232           </para>
2233
2234           <xi:include href="version-info.xml" xpointer="v240"/>
2235         </listitem>
2236       </varlistentry>
2237
2238       <varlistentry>
2239         <term><varname>FailOverMACPolicy=</varname></term>
2240         <listitem>
2241           <para>Specifies whether the active-backup mode should set all slaves to
2242           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
2243           bond's MAC address in accordance with the selected policy. The default policy is none.
2244           Possible values are
2245           <literal>none</literal>,
2246           <literal>active</literal> and
2247           <literal>follow</literal>.
2248           </para>
2249
2250           <xi:include href="version-info.xml" xpointer="v220"/>
2251         </listitem>
2252       </varlistentry>
2253
2254       <varlistentry>
2255         <term><varname>ARPValidate=</varname></term>
2256         <listitem>
2257           <para>Specifies whether or not ARP probes and replies should be
2258           validated in any mode that supports ARP monitoring, or whether
2259           non-ARP traffic should be filtered (disregarded) for link
2260           monitoring purposes. Possible values are
2261           <literal>none</literal>,
2262           <literal>active</literal>,
2263           <literal>backup</literal> and
2264           <literal>all</literal>.
2265           </para>
2266
2267           <xi:include href="version-info.xml" xpointer="v220"/>
2268         </listitem>
2269       </varlistentry>
2270
2271       <varlistentry>
2272         <term><varname>ARPIntervalSec=</varname></term>
2273         <listitem>
2274           <para>Specifies the ARP link monitoring frequency. A value of 0 disables ARP monitoring. The
2275           default value is 0, and the default unit seconds.
2276           </para>
2277
2278           <xi:include href="version-info.xml" xpointer="v220"/>
2279         </listitem>
2280       </varlistentry>
2281
2282       <varlistentry>
2283         <term><varname>ARPIPTargets=</varname></term>
2284         <listitem>
2285           <para>Specifies the IP addresses to use as ARP monitoring peers when
2286           <varname>ARPIntervalSec=</varname> is greater than 0. These are the targets of the ARP
2287           request sent to determine the health of the link to the targets.
2288           Specify these values in IPv4 dotted decimal format. At least one IP
2289           address must be given for ARP monitoring to function. The
2290           maximum number of targets that can be specified is 16. The
2291           default value is no IP addresses.
2292           </para>
2293
2294           <xi:include href="version-info.xml" xpointer="v220"/>
2295         </listitem>
2296       </varlistentry>
2297
2298       <varlistentry>
2299         <term><varname>ARPAllTargets=</varname></term>
2300         <listitem>
2301           <para>Specifies the quantity of <varname>ARPIPTargets=</varname> that must be reachable
2302           in order for the ARP monitor to consider a slave as being up.
2303           This option affects only active-backup mode for slaves with
2304           ARPValidate enabled. Possible values are
2305           <literal>any</literal> and
2306           <literal>all</literal>.
2307           </para>
2308
2309         <xi:include href="version-info.xml" xpointer="v220"/>
2310         </listitem>
2311       </varlistentry>
2312
2313       <varlistentry>
2314         <term><varname>PrimaryReselectPolicy=</varname></term>
2315         <listitem>
2316           <para>Specifies the reselection policy for the primary slave.  This
2317           affects how the primary slave is chosen to become the active slave
2318           when failure of the active slave or recovery of the primary slave
2319           occurs. This option is designed to prevent flip-flopping between
2320           the primary slave and other slaves.  Possible values are
2321           <literal>always</literal>,
2322           <literal>better</literal> and
2323           <literal>failure</literal>.
2324           </para>
2325
2326           <xi:include href="version-info.xml" xpointer="v220"/>
2327         </listitem>
2328       </varlistentry>
2329
2330       <varlistentry>
2331         <term><varname>ResendIGMP=</varname></term>
2332         <listitem>
2333           <para>Specifies the number of IGMP membership reports to be issued after
2334           a failover event. One membership report is issued immediately after
2335           the failover, subsequent packets are sent in each 200ms interval.
2336           The valid range is 0…255. Defaults to 1. A value of 0
2337           prevents the IGMP membership report from being issued in response
2338           to the failover event.
2339           </para>
2340
2341           <xi:include href="version-info.xml" xpointer="v220"/>
2342         </listitem>
2343       </varlistentry>
2344
2345       <varlistentry>
2346         <term><varname>PacketsPerSlave=</varname></term>
2347         <listitem>
2348           <para>Specify the number of packets to transmit through a slave before
2349           moving to the next one. When set to 0, then a slave is chosen at
2350           random. The valid range is 0…65535. Defaults to 1. This option
2351           only has effect when in balance-rr mode.
2352           </para>
2353
2354           <xi:include href="version-info.xml" xpointer="v220"/>
2355         </listitem>
2356       </varlistentry>
2357
2358       <varlistentry>
2359         <term><varname>GratuitousARP=</varname></term>
2360         <listitem>
2361           <para>Specify the number of peer notifications (gratuitous ARPs and
2362           unsolicited IPv6 Neighbor Advertisements) to be issued after a
2363           failover event.  As soon as the link is up on the new slave,
2364           a peer notification is sent on the  bonding device and each
2365           VLAN sub-device.  This is repeated at each link monitor interval
2366           (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
2367           greater than 1. The valid range is 0…255. The default value is 1.
2368           These options affect only the active-backup mode.
2369           </para>
2370
2371           <xi:include href="version-info.xml" xpointer="v220"/>
2372         </listitem>
2373       </varlistentry>
2374
2375       <varlistentry>
2376         <term><varname>AllSlavesActive=</varname></term>
2377         <listitem>
2378           <para>Takes a boolean. Specifies that duplicate frames (received on inactive ports)
2379           should be dropped when false, or delivered when true. Normally, bonding will drop
2380           duplicate frames (received on inactive ports), which is desirable for
2381           most users. But there are some times it is nice to allow duplicate
2382           frames to be delivered. The default value is false (drop duplicate frames
2383           received on inactive ports).
2384           </para>
2385
2386           <xi:include href="version-info.xml" xpointer="v220"/>
2387         </listitem>
2388       </varlistentry>
2389
2390       <varlistentry>
2391         <term><varname>DynamicTransmitLoadBalancing=</varname></term>
2392         <listitem>
2393           <para>Takes a boolean. Specifies if dynamic shuffling of flows is enabled. Applies only
2394           for balance-tlb mode. Defaults to unset.
2395           </para>
2396
2397           <xi:include href="version-info.xml" xpointer="v240"/>
2398         </listitem>
2399       </varlistentry>
2400
2401       <varlistentry>
2402         <term><varname>MinLinks=</varname></term>
2403         <listitem>
2404           <para>Specifies the minimum number of links that must be active before
2405           asserting carrier. The default value is 0.
2406           </para>
2407
2408           <xi:include href="version-info.xml" xpointer="v220"/>
2409         </listitem>
2410       </varlistentry>
2411     </variablelist>
2412
2413     <para>For more detail information see
2414     <ulink url="https://docs.kernel.org/networking/bonding.html">
2415     Linux Ethernet Bonding Driver HOWTO</ulink></para>
2416   </refsect1>
2417
2418   <refsect1>
2419     <title>[Xfrm] Section Options</title>
2420
2421     <para>The [Xfrm] section accepts the following
2422     keys:</para>
2423
2424     <variablelist class='network-directives'>
2425       <varlistentry>
2426         <term><varname>InterfaceId=</varname></term>
2427         <listitem>
2428           <para>Sets the ID/key of the xfrm interface which needs to be associated with a SA/policy.
2429           Can be decimal or hexadecimal, valid range is 1-0xffffffff. This is mandatory.</para>
2430
2431           <xi:include href="version-info.xml" xpointer="v243"/>
2432         </listitem>
2433       </varlistentry>
2434       <varlistentry>
2435         <term><varname>Independent=</varname></term>
2436         <listitem>
2437           <para>Takes a boolean. If false (the default), the xfrm interface must have an underlying device
2438           which can be used for hardware offloading.</para>
2439
2440           <xi:include href="version-info.xml" xpointer="v243"/>
2441         </listitem>
2442       </varlistentry>
2443     </variablelist>
2444
2445     <para>For more detail information see
2446       <ulink url="https://lwn.net/Articles/757391">Virtual XFRM Interfaces</ulink>.</para>
2447   </refsect1>
2448
2449   <refsect1>
2450     <title>[VRF] Section Options</title>
2451     <para>The [VRF] section only applies for
2452     netdevs of kind <literal>vrf</literal> and accepts the
2453     following key:</para>
2454
2455     <variablelist class='network-directives'>
2456       <varlistentry>
2457         <term><varname>Table=</varname></term>
2458         <listitem>
2459           <para>The numeric routing table identifier. This setting is compulsory.</para>
2460
2461         <xi:include href="version-info.xml" xpointer="v243"/>
2462         </listitem>
2463       </varlistentry>
2464     </variablelist>
2465   </refsect1>
2466
2467   <refsect1>
2468     <title>[BatmanAdvanced] Section Options</title>
2469
2470     <para>The [BatmanAdvanced] section only applies for netdevs of kind <literal>batadv</literal> and accepts
2471     the following keys:</para>
2472
2473     <variablelist class='network-directives'>
2474       <varlistentry>
2475         <term><varname>GatewayMode=</varname></term>
2476         <listitem>
2477           <para>Takes one of <literal>off</literal>, <literal>server</literal>, or <literal>client</literal>.
2478           A batman-adv node can either run in server mode (sharing its internet
2479           connection with the mesh) or in client mode (searching for the most suitable internet connection
2480           in the mesh) or having the gateway support turned off entirely (which is the default setting).
2481           </para>
2482
2483         <xi:include href="version-info.xml" xpointer="v248"/>
2484         </listitem>
2485       </varlistentry>
2486       <varlistentry>
2487         <term><varname>Aggregation=</varname></term>
2488         <listitem>
2489           <para>Takes a boolean value. Enables or disables aggregation of originator messages. Defaults to
2490            true.
2491           </para>
2492
2493           <xi:include href="version-info.xml" xpointer="v248"/>
2494         </listitem>
2495       </varlistentry>
2496       <varlistentry>
2497         <term><varname>BridgeLoopAvoidance=</varname></term>
2498         <listitem>
2499           <para>Takes a boolean value. Enables or disables avoidance of loops on bridges. Defaults to true.
2500           </para>
2501
2502           <xi:include href="version-info.xml" xpointer="v248"/>
2503         </listitem>
2504       </varlistentry>
2505       <varlistentry>
2506         <term><varname>DistributedArpTable=</varname></term>
2507         <listitem>
2508           <para>Takes a boolean value. Enables or disables the distributed ARP table. Defaults to true.</para>
2509
2510         <xi:include href="version-info.xml" xpointer="v248"/>
2511         </listitem>
2512       </varlistentry>
2513       <varlistentry>
2514         <term><varname>Fragmentation=</varname></term>
2515         <listitem>
2516           <para>Takes a boolean value. Enables or disables fragmentation. Defaults to true.</para>
2517
2518         <xi:include href="version-info.xml" xpointer="v248"/>
2519         </listitem>
2520       </varlistentry>
2521       <varlistentry>
2522         <term><varname>HopPenalty=</varname></term>
2523         <listitem>
2524           <para>The hop penalty setting allows one to modify
2525           <citerefentry project='mankier'><refentrytitle>batctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
2526           preference for multihop routes vs. short routes. This integer value is applied to the
2527           TQ (Transmit Quality) of each forwarded OGM (Originator Message), thereby propagating the
2528           cost of an extra hop (the packet has to be received and retransmitted which costs airtime).
2529           A higher hop penalty will make it more unlikely that other nodes will choose this node as
2530           intermediate hop towards any given destination. The default hop penalty of '15' is a reasonable
2531           value for most setups and probably does not need to be changed. However, mobile nodes could
2532           choose a value of 255 (maximum value) to avoid being chosen as a router by other nodes.
2533           The minimum value is 0.
2534           </para>
2535
2536           <xi:include href="version-info.xml" xpointer="v248"/>
2537         </listitem>
2538       </varlistentry>
2539       <varlistentry>
2540         <term><varname>OriginatorIntervalSec=</varname></term>
2541         <listitem>
2542           <para>The value specifies the interval in seconds, unless another time unit is specified in which
2543           batman-adv floods the network with its protocol information.
2544           See <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
2545           for more information.</para>
2546
2547           <xi:include href="version-info.xml" xpointer="v248"/>
2548         </listitem>
2549       </varlistentry>
2550       <varlistentry>
2551         <term><varname>GatewayBandwidthDown=</varname></term>
2552         <listitem>
2553           <para>If the node is a server, this
2554           parameter is used to inform other nodes in the network about
2555           this node's internet connection download bandwidth in bits per second. Just enter any number
2556           suffixed with K, M, G or T (base 1000) and the batman-adv
2557           module will propagate the entered value in the mesh.</para>
2558
2559           <xi:include href="version-info.xml" xpointer="v248"/>
2560         </listitem>
2561       </varlistentry>
2562       <varlistentry>
2563         <term><varname>GatewayBandwidthUp=</varname></term>
2564         <listitem>
2565           <para>If the node is a server, this
2566           parameter is used to inform other nodes in the network about
2567           this node's internet connection upload bandwidth in bits per second. Just enter any number
2568           suffixed with K, M, G or T (base 1000) and the batman-adv
2569           module will propagate the entered value in the mesh.</para>
2570
2571           <xi:include href="version-info.xml" xpointer="v248"/>
2572         </listitem>
2573       </varlistentry>
2574       <varlistentry>
2575         <term><varname>RoutingAlgorithm=</varname></term>
2576         <listitem>
2577           <para>This can be either <literal>batman-v</literal> or <literal>batman-iv</literal> and describes which routing_algo
2578           of <citerefentry project='mankier'><refentrytitle>batctl</refentrytitle><manvolnum>8</manvolnum></citerefentry> to use. The algorithm
2579           cannot be changed after interface creation. Defaults to <literal>batman-v</literal>.
2580           </para>
2581
2582         <xi:include href="version-info.xml" xpointer="v248"/>
2583         </listitem>
2584       </varlistentry>
2585     </variablelist>
2586   </refsect1>
2587
2588   <refsect1>
2589     <title>[IPoIB] Section Options</title>
2590     <para>The [IPoIB] section only applies for netdevs of kind <literal>ipoib</literal> and accepts the
2591     following keys:</para>
2592
2593     <variablelist class='network-directives'>
2594       <varlistentry>
2595         <term><varname>PartitionKey=</varname></term>
2596         <listitem>
2597           <para>Takes an integer in the range 1…0xffff, except for 0x8000. Defaults to unset, and the
2598           kernel's default is used.</para>
2599
2600           <xi:include href="version-info.xml" xpointer="v250"/>
2601         </listitem>
2602       </varlistentry>
2603
2604       <varlistentry id='ipoib_mode'>
2605         <term><varname>Mode=</varname></term>
2606         <listitem>
2607           <para>Takes one of the special values <literal>datagram</literal> or
2608           <literal>connected</literal>. Defaults to unset, and the kernel's default is used.</para>
2609
2610           <para>When <literal>datagram</literal>, the Infiniband unreliable datagram (UD) transport is
2611           used, and so the interface MTU is equal to the IB L2 MTU minus the IPoIB encapsulation
2612           header (4 bytes). For example, in a typical IB fabric with a 2K MTU, the IPoIB MTU will be
2613           2048 - 4 = 2044 bytes.</para>
2614
2615           <para>When <literal>connected</literal>, the Infiniband reliable connected (RC) transport is
2616           used. Connected mode takes advantage of the connected nature of the IB transport and allows
2617           an MTU up to the maximal IP packet size of 64K, which reduces the number of IP packets needed
2618           for handling large UDP datagrams, TCP segments, etc and increases the performance for large
2619           messages.</para>
2620
2621           <xi:include href="version-info.xml" xpointer="v250"/>
2622         </listitem>
2623       </varlistentry>
2624
2625       <varlistentry id='ipoib_umcast'>
2626         <term><varname>IgnoreUserspaceMulticastGroup=</varname></term>
2627         <listitem>
2628           <para>Takes an boolean value. When true, the kernel ignores multicast groups handled by
2629           userspace. Defaults to unset, and the kernel's default is used.</para>
2630
2631           <xi:include href="version-info.xml" xpointer="v250"/>
2632         </listitem>
2633       </varlistentry>
2634     </variablelist>
2635   </refsect1>
2636
2637   <refsect1>
2638     <title>[WLAN] Section Options</title>
2639     <para>The [WLAN] section only applies to WLAN interfaces, and accepts the following keys:</para>
2640
2641     <variablelist class='network-directives'>
2642       <varlistentry>
2643         <term><varname>PhysicalDevice=</varname></term>
2644         <listitem>
2645           <para>Specifies the name or index of the physical WLAN device (e.g. <literal>0</literal> or
2646           <literal>phy0</literal>). The list of the physical WLAN devices that exist on the host can be
2647           obtained by <command>iw phy</command> command. This option is mandatory.</para>
2648
2649         <xi:include href="version-info.xml" xpointer="v251"/>
2650         </listitem>
2651       </varlistentry>
2652
2653       <varlistentry>
2654         <term><varname>Type=</varname></term>
2655         <listitem>
2656           <para>Specifies the type of the interface. Takes one of the <literal>ad-hoc</literal>,
2657           <literal>station</literal>, <literal>ap</literal>, <literal>ap-vlan</literal>,
2658           <literal>wds</literal>, <literal>monitor</literal>, <literal>mesh-point</literal>,
2659           <literal>p2p-client</literal>, <literal>p2p-go</literal>, <literal>p2p-device</literal>,
2660           <literal>ocb</literal>, and <literal>nan</literal>. This option is mandatory.</para>
2661
2662         <xi:include href="version-info.xml" xpointer="v251"/>
2663         </listitem>
2664       </varlistentry>
2665
2666       <varlistentry>
2667         <term><varname>WDS=</varname></term>
2668         <listitem>
2669           <para>Enables the Wireless Distribution System (WDS) mode on the interface. The mode is also
2670           known as the <literal>4 address mode</literal>. Takes a boolean value. Defaults to unset, and
2671           the kernel's default will be used.</para>
2672
2673           <xi:include href="version-info.xml" xpointer="v251"/>
2674         </listitem>
2675       </varlistentry>
2676     </variablelist>
2677   </refsect1>
2678
2679   <refsect1>
2680     <title>Examples</title>
2681     <example>
2682       <title>/etc/systemd/network/25-bridge.netdev</title>
2683
2684       <programlisting>[NetDev]
2685 Name=bridge0
2686 Kind=bridge</programlisting>
2687     </example>
2688
2689     <example>
2690       <title>/etc/systemd/network/25-vlan1.netdev</title>
2691
2692       <programlisting>[Match]
2693 Virtualization=no
2694
2695 [NetDev]
2696 Name=vlan1
2697 Kind=vlan
2698
2699 [VLAN]
2700 Id=1</programlisting>
2701     </example>
2702     <example>
2703       <title>/etc/systemd/network/25-ipip.netdev</title>
2704       <programlisting>[NetDev]
2705 Name=ipip-tun
2706 Kind=ipip
2707 MTUBytes=1480
2708
2709 [Tunnel]
2710 Local=192.168.223.238
2711 Remote=192.169.224.239
2712 TTL=64</programlisting>
2713     </example>
2714     <example>
2715       <title>/etc/systemd/network/1-fou-tunnel.netdev</title>
2716       <programlisting>[NetDev]
2717 Name=fou-tun
2718 Kind=fou
2719
2720 [FooOverUDP]
2721 Port=5555
2722 Protocol=4
2723       </programlisting>
2724     </example>
2725     <example>
2726       <title>/etc/systemd/network/25-fou-ipip.netdev</title>
2727       <programlisting>[NetDev]
2728 Name=ipip-tun
2729 Kind=ipip
2730
2731 [Tunnel]
2732 Independent=yes
2733 Local=10.65.208.212
2734 Remote=10.65.208.211
2735 FooOverUDP=yes
2736 FOUDestinationPort=5555
2737       </programlisting>
2738     </example>
2739     <example>
2740       <title>/etc/systemd/network/25-tap.netdev</title>
2741       <programlisting>[NetDev]
2742 Name=tap-test
2743 Kind=tap
2744
2745 [Tap]
2746 MultiQueue=yes
2747 PacketInfo=yes</programlisting> </example>
2748
2749     <example>
2750       <title>/etc/systemd/network/25-sit.netdev</title>
2751       <programlisting>[NetDev]
2752 Name=sit-tun
2753 Kind=sit
2754 MTUBytes=1480
2755
2756 [Tunnel]
2757 Local=10.65.223.238
2758 Remote=10.65.223.239</programlisting>
2759     </example>
2760
2761     <example>
2762       <title>/etc/systemd/network/25-6rd.netdev</title>
2763       <programlisting>[NetDev]
2764 Name=6rd-tun
2765 Kind=sit
2766 MTUBytes=1480
2767
2768 [Tunnel]
2769 Local=10.65.223.238
2770 IPv6RapidDeploymentPrefix=2602::/24</programlisting>
2771     </example>
2772
2773     <example>
2774       <title>/etc/systemd/network/25-gre.netdev</title>
2775       <programlisting>[NetDev]
2776 Name=gre-tun
2777 Kind=gre
2778 MTUBytes=1480
2779
2780 [Tunnel]
2781 Local=10.65.223.238
2782 Remote=10.65.223.239</programlisting>
2783     </example>
2784
2785     <example>
2786       <title>/etc/systemd/network/25-ip6gre.netdev</title>
2787       <programlisting>[NetDev]
2788 Name=ip6gre-tun
2789 Kind=ip6gre
2790
2791 [Tunnel]
2792 Key=123</programlisting>
2793     </example>
2794
2795     <example>
2796       <title>/etc/systemd/network/25-vti.netdev</title>
2797
2798       <programlisting>[NetDev]
2799 Name=vti-tun
2800 Kind=vti
2801 MTUBytes=1480
2802
2803 [Tunnel]
2804 Local=10.65.223.238
2805 Remote=10.65.223.239</programlisting>
2806     </example>
2807
2808     <example>
2809       <title>/etc/systemd/network/25-veth.netdev</title>
2810       <programlisting>[NetDev]
2811 Name=veth-test
2812 Kind=veth
2813
2814 [Peer]
2815 Name=veth-peer</programlisting>
2816     </example>
2817
2818     <example>
2819       <title>/etc/systemd/network/25-bond.netdev</title>
2820       <programlisting>[NetDev]
2821 Name=bond1
2822 Kind=bond
2823
2824 [Bond]
2825 Mode=802.3ad
2826 TransmitHashPolicy=layer3+4
2827 MIIMonitorSec=1s
2828 LACPTransmitRate=fast
2829 </programlisting>
2830     </example>
2831
2832     <example>
2833       <title>/etc/systemd/network/25-dummy.netdev</title>
2834       <programlisting>[NetDev]
2835 Name=dummy-test
2836 Kind=dummy
2837 MACAddress=12:34:56:78:9a:bc</programlisting>
2838     </example>
2839     <example>
2840       <title>/etc/systemd/network/25-vrf.netdev</title>
2841       <para>Create a VRF interface with table 42.</para>
2842       <programlisting>[NetDev]
2843 Name=vrf-test
2844 Kind=vrf
2845
2846 [VRF]
2847 Table=42</programlisting>
2848     </example>
2849
2850     <example>
2851       <title>/etc/systemd/network/25-macvtap.netdev</title>
2852       <para>Create a MacVTap device.</para>
2853       <programlisting>[NetDev]
2854 Name=macvtap-test
2855 Kind=macvtap
2856       </programlisting>
2857     </example>
2858     <example>
2859       <title>/etc/systemd/network/25-wireguard.netdev</title>
2860       <programlisting>[NetDev]
2861 Name=wg0
2862 Kind=wireguard
2863
2864 [WireGuard]
2865 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
2866 ListenPort=51820
2867
2868 [WireGuardPeer]
2869 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
2870 AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
2871 Endpoint=wireguard.example.com:51820</programlisting>
2872     </example>
2873
2874     <example>
2875       <title>/etc/systemd/network/27-xfrm.netdev</title>
2876       <programlisting>[NetDev]
2877 Name=xfrm0
2878 Kind=xfrm
2879
2880 [Xfrm]
2881 Independent=yes</programlisting>
2882     </example>
2883   </refsect1>
2884
2885   <refsect1>
2886     <title>See Also</title>
2887     <para>
2888       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
2889       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
2890       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
2891       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
2892       <citerefentry><refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
2893     </para>
2894   </refsect1>
2895
2896 </refentry>