man/systemd.netdev.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7
   8   This file is part of systemd.
   9
  10   Copyright 2013 Tom Gundersen
  11 -->
  12
  13 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>
  14
  15   <refentryinfo>
  16     <title>systemd.network</title>
  17     <productname>systemd</productname>
  18
  19     <authorgroup>
  20       <author>
  21         <contrib>Developer</contrib>
  22         <firstname>Tom</firstname>
  23         <surname>Gundersen</surname>
  24         <email>teg@jklm.no</email>
  25       </author>
  26     </authorgroup>
  27   </refentryinfo>
  28
  29   <refmeta>
  30     <refentrytitle>systemd.netdev</refentrytitle>
  31     <manvolnum>5</manvolnum>
  32   </refmeta>
  33
  34   <refnamediv>
  35     <refname>systemd.netdev</refname>
  36     <refpurpose>Virtual Network Device configuration</refpurpose>
  37   </refnamediv>
  38
  39   <refsynopsisdiv>
  40     <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  41   </refsynopsisdiv>
  42
  43   <refsect1>
  44     <title>Description</title>
  45
  46     <para>Network setup is performed by
  47     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  48     </para>
  49
  50     <para>The main Virtual Network Device file must have the extension <filename>.netdev</filename>;
  51     other extensions are ignored. Virtual network devices are created as soon as networkd is
  52     started. If a netdev with the specified name already exists, networkd will use that as-is rather
  53     than create its own. Note that the settings of the pre-existing netdev will not be changed by
  54     networkd.</para>
  55
  56     <para>The <filename>.netdev</filename> files are read from the files located in the system
  57     network directory <filename>/usr/lib/systemd/network</filename>, the volatile runtime network
  58     directory <filename>/run/systemd/network</filename> and the local administration network
  59     directory <filename>/etc/systemd/network</filename>. All configuration files are collectively
  60     sorted and processed in lexical order, regardless of the directories in which they live.
  61     However, files with identical filenames replace each other. Files in <filename>/etc</filename>
  62     have the highest priority, files in <filename>/run</filename> take precedence over files with
  63     the same name in <filename>/usr/lib</filename>. This can be used to override a system-supplied
  64     configuration file with a local file if needed. As a special case, an empty file (file size 0)
  65     or symlink with the same name pointing to <filename>/dev/null</filename> disables the
  66     configuration file entirely (it is "masked").</para>
  67
  68     <para>Along with the netdev file <filename>foo.netdev</filename>, a "drop-in" directory
  69     <filename>foo.netdev.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  70     from this directory will be parsed after the file itself is parsed. This is useful to alter or
  71     add configuration settings, without having to modify the main configuration file. Each drop-in
  72     file must have appropriate section headers.</para>
  73
  74     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  75     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  76     <filename>/run/systemd/network</filename> directories. Drop-in files in
  77     <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
  78     take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
  79     directories take precedence over the main netdev file wherever located. (Of course, since
  80     <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is
  81     unlikely drop-ins should be used in either of those places.)</para>
  82   </refsect1>
  83
  84   <refsect1>
  85     <title>Supported netdev kinds</title>
  86
  87     <para>The following kinds of virtual network devices may be
  88     configured in <filename>.netdev</filename> files:</para>
  89
  90     <table>
  91       <title>Supported kinds of virtual network devices</title>
  92
  93       <tgroup cols='2'>
  94         <colspec colname='kind' />
  95         <colspec colname='explanation' />
  96         <thead><row>
  97           <entry>Kind</entry>
  98           <entry>Description</entry>
  99         </row></thead>
 100         <tbody>
 101           <row><entry><varname>bond</varname></entry>
 102           <entry>A bond device is an aggregation of all its slave devices. See <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">Linux Ethernet Bonding Driver HOWTO</ulink> for details.Local configuration</entry></row>
 103
 104           <row><entry><varname>bridge</varname></entry>
 105           <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>
 106
 107           <row><entry><varname>dummy</varname></entry>
 108           <entry>A dummy device drops all packets sent to it.</entry></row>
 109
 110           <row><entry><varname>gre</varname></entry>
 111           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
 112
 113           <row><entry><varname>gretap</varname></entry>
 114           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 115
 116           <row><entry><varname>ip6gre</varname></entry>
 117           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 118
 119           <row><entry><varname>ip6tnl</varname></entry>
 120           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 121
 122           <row><entry><varname>ip6gretap</varname></entry>
 123           <entry>A Level 2 GRE tunnel over IPv6.</entry></row>
 124
 125           <row><entry><varname>ipip</varname></entry>
 126           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 127
 128           <row><entry><varname>ipvlan</varname></entry>
 129           <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 130
 131           <row><entry><varname>macvlan</varname></entry>
 132           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 133
 134           <row><entry><varname>macvtap</varname></entry>
 135           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 136
 137           <row><entry><varname>sit</varname></entry>
 138           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 139
 140           <row><entry><varname>tap</varname></entry>
 141           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 142
 143           <row><entry><varname>tun</varname></entry>
 144           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 145
 146           <row><entry><varname>veth</varname></entry>
 147           <entry>An Ethernet tunnel between a pair of network devices.</entry></row>
 148
 149           <row><entry><varname>vlan</varname></entry>
 150           <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>
 151
 152           <row><entry><varname>vti</varname></entry>
 153           <entry>An IPv4 over IPSec tunnel.</entry></row>
 154
 155           <row><entry><varname>vti6</varname></entry>
 156           <entry>An IPv6 over IPSec tunnel.</entry></row>
 157
 158           <row><entry><varname>vxlan</varname></entry>
 159           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 160
 161           <row><entry><varname>geneve</varname></entry>
 162           <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.</entry></row>
 163
 164           <row><entry><varname>vrf</varname></entry>
 165           <entry>A Virtual Routing and Forwarding (<ulink url="https://www.kernel.org/doc/Documentation/networking/vrf.txt">VRF</ulink>) interface to create separate routing and forwarding domains.</entry></row>
 166
 167           <row><entry><varname>vcan</varname></entry>
 168           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 169
 170           <row><entry><varname>vxcan</varname></entry>
 171           <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.
 172           </entry></row>
 173
 174           <row><entry><varname>wireguard</varname></entry>
 175           <entry>WireGuard Secure Network Tunnel.</entry></row>
 176
 177         </tbody>
 178       </tgroup>
 179     </table>
 180
 181   </refsect1>
 182
 183   <refsect1>
 184     <title>[Match] Section Options</title>
 185
 186     <para>A virtual network device is only created if the
 187     <literal>[Match]</literal> section matches the current
 188     environment, or if the section is empty. The following keys are
 189     accepted:</para>
 190
 191     <variablelist class='network-directives'>
 192       <varlistentry>
 193         <term><varname>Host=</varname></term>
 194         <listitem>
 195           <para>Matches against the hostname or machine ID of the
 196           host. See <literal>ConditionHost=</literal> in
 197           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 198           for details.
 199           </para>
 200         </listitem>
 201       </varlistentry>
 202       <varlistentry>
 203         <term><varname>Virtualization=</varname></term>
 204         <listitem>
 205           <para>Checks whether the system is executed in a virtualized
 206           environment and optionally test whether it is a specific
 207           implementation. See
 208           <literal>ConditionVirtualization=</literal> in
 209           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 210           for details.
 211           </para>
 212         </listitem>
 213       </varlistentry>
 214       <varlistentry>
 215         <term><varname>KernelCommandLine=</varname></term>
 216         <listitem>
 217           <para>Checks whether a specific kernel command line option
 218           is set (or if prefixed with the exclamation mark unset). See
 219           <literal>ConditionKernelCommandLine=</literal> in
 220           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 221           for details.
 222           </para>
 223         </listitem>
 224       </varlistentry>
 225       <varlistentry>
 226         <term><varname>KernelVersion=</varname></term>
 227         <listitem>
 228           <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a certain
 229           expression (or if prefixed with the exclamation mark does not match it). See
 230           <literal>ConditionKernelVersion=</literal> in
 231           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
 232           </para>
 233         </listitem>
 234       </varlistentry>
 235       <varlistentry>
 236         <term><varname>Architecture=</varname></term>
 237         <listitem>
 238           <para>Checks whether the system is running on a specific
 239           architecture. See <literal>ConditionArchitecture=</literal> in
 240           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 241           for details.
 242           </para>
 243         </listitem>
 244       </varlistentry>
 245     </variablelist>
 246
 247   </refsect1>
 248
 249   <refsect1>
 250     <title>[NetDev] Section Options</title>
 251
 252       <para>The <literal>[NetDev]</literal> section accepts the
 253       following keys:</para>
 254
 255       <variablelist class='network-directives'>
 256         <varlistentry>
 257           <term><varname>Description=</varname></term>
 258           <listitem>
 259             <para>A free-form description of the netdev.</para>
 260           </listitem>
 261         </varlistentry>
 262         <varlistentry>
 263           <term><varname>Name=</varname></term>
 264           <listitem>
 265             <para>The interface name used when creating the netdev.
 266             This option is compulsory.</para>
 267           </listitem>
 268         </varlistentry>
 269         <varlistentry>
 270           <term><varname>Kind=</varname></term>
 271           <listitem>
 272             <para>The netdev kind. This option is compulsory. See the
 273             <literal>Supported netdev kinds</literal> section for the
 274             valid keys.</para>
 275           </listitem>
 276         </varlistentry>
 277         <varlistentry>
 278           <term><varname>MTUBytes=</varname></term>
 279           <listitem>
 280             <para>The maximum transmission unit in bytes to set for
 281             the device. The usual suffixes K, M, G, are supported and
 282             are understood to the base of 1024. This key is not
 283             currently supported for <literal>tun</literal> or
 284             <literal>tap</literal> devices.
 285             </para>
 286           </listitem>
 287         </varlistentry>
 288         <varlistentry>
 289           <term><varname>MACAddress=</varname></term>
 290           <listitem>
 291             <para>The MAC address to use for the device. If none is
 292             given, one is generated based on the interface name and
 293             the
 294             <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 295             This key is not currently supported for
 296             <literal>tun</literal> or <literal>tap</literal> devices.
 297             </para>
 298           </listitem>
 299         </varlistentry>
 300       </variablelist>
 301   </refsect1>
 302
 303     <refsect1>
 304     <title>[Bridge] Section Options</title>
 305
 306       <para>The <literal>[Bridge]</literal> section only applies for
 307       netdevs of kind <literal>bridge</literal>, and accepts the
 308       following keys:</para>
 309
 310       <variablelist class='network-directives'>
 311         <varlistentry>
 312           <term><varname>HelloTimeSec=</varname></term>
 313           <listitem>
 314             <para>HelloTimeSec specifies the number of seconds between two hello packets
 315             sent out by the root bridge and the designated bridges. Hello packets are
 316             used to communicate information about the topology throughout the entire
 317             bridged local area network.</para>
 318           </listitem>
 319         </varlistentry>
 320         <varlistentry>
 321           <term><varname>MaxAgeSec=</varname></term>
 322           <listitem>
 323             <para>MaxAgeSec specifies the number of seconds of maximum message age.
 324             If the last seen (received) hello packet is more than this number of
 325             seconds old, the bridge in question will start the takeover procedure
 326             in attempt to become the Root Bridge itself.</para>
 327           </listitem>
 328         </varlistentry>
 329         <varlistentry>
 330           <term><varname>ForwardDelaySec=</varname></term>
 331           <listitem>
 332             <para>ForwardDelaySec specifies the number of seconds spent in each
 333             of the Listening and Learning states before the Forwarding state is entered.</para>
 334           </listitem>
 335         </varlistentry>
 336         <varlistentry>
 337           <term><varname>AgeingTimeSec=</varname></term>
 338           <listitem>
 339             <para>This specifies the number of seconds a MAC Address will be kept in
 340             the forwarding database after having a packet received from this MAC Address.</para>
 341           </listitem>
 342         </varlistentry>
 343         <varlistentry>
 344           <term><varname>Priority=</varname></term>
 345           <listitem>
 346             <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 347             means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 348           </listitem>
 349         </varlistentry>
 350         <varlistentry>
 351           <term><varname>GroupForwardMask=</varname></term>
 352           <listitem>
 353             <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 354             local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 355             is performed between the specified bitmask and the exponentiation of 2^X, the
 356             lower nibble of the last octet of the MAC address. For example, a value of 8
 357             would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 358           </listitem>
 359         </varlistentry>
 360         <varlistentry>
 361           <term><varname>DefaultPVID=</varname></term>
 362           <listitem>
 363             <para>This specifies the default port VLAN ID of a newly attached bridge port.
 364             Set this to an integer in the range 1–4094 or <literal>none</literal> to disable the PVID.</para>
 365           </listitem>
 366         </varlistentry>
 367         <varlistentry>
 368           <term><varname>MulticastQuerier=</varname></term>
 369           <listitem>
 370             <para>A boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 371             If enabled, the kernel will send general ICMP queries from a zero source address.
 372             This feature should allow faster convergence on startup, but it causes some
 373             multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 374             When unset, the kernel's default setting applies.
 375             </para>
 376           </listitem>
 377         </varlistentry>
 378         <varlistentry>
 379           <term><varname>MulticastSnooping=</varname></term>
 380           <listitem>
 381             <para>A boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
 382             If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
 383             between hosts and multicast routers. When unset, the kernel's default setting applies.
 384             </para>
 385           </listitem>
 386         </varlistentry>
 387         <varlistentry>
 388           <term><varname>VLANFiltering=</varname></term>
 389           <listitem>
 390             <para>A boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 391             If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's
 392             default setting applies.
 393             </para>
 394           </listitem>
 395         </varlistentry>
 396           <varlistentry>
 397           <term><varname>STP=</varname></term>
 398           <listitem>
 399             <para>A boolean. This enables the bridge's Spanning Tree Protocol (STP). When unset,
 400             the kernel's default setting applies.
 401             </para>
 402           </listitem>
 403         </varlistentry>
 404       </variablelist>
 405   </refsect1>
 406
 407   <refsect1>
 408     <title>[VLAN] Section Options</title>
 409
 410       <para>The <literal>[VLAN]</literal> section only applies for
 411       netdevs of kind <literal>vlan</literal>, and accepts the
 412       following key:</para>
 413
 414       <variablelist class='network-directives'>
 415         <varlistentry>
 416           <term><varname>Id=</varname></term>
 417           <listitem>
 418             <para>The VLAN ID to use. An integer in the range 0–4094.
 419             This option is compulsory.</para>
 420           </listitem>
 421         </varlistentry>
 422         <varlistentry>
 423           <term><varname>GVRP=</varname></term>
 424           <listitem>
 425             <para>The Generic VLAN Registration Protocol (GVRP) is a protocol that
 426             allows automatic learning of VLANs on a network. A boolean. When unset,
 427             the kernel's default setting applies.</para>
 428           </listitem>
 429         </varlistentry>
 430         <varlistentry>
 431           <term><varname>MVRP=</varname></term>
 432           <listitem>
 433             <para>Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 434             Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 435             for automatic configuration of VLAN information on switches. It was defined
 436             in the 802.1ak amendment to 802.1Q-2005. A boolean. When unset, the kernel's
 437             default setting applies.</para>
 438           </listitem>
 439         </varlistentry>
 440         <varlistentry>
 441           <term><varname>LooseBinding=</varname></term>
 442           <listitem>
 443             <para>The VLAN loose binding mode, in which only the operational state is passed
 444             from the parent to the associated VLANs, but the VLAN device state is not changed.
 445             A boolean. When unset, the kernel's default setting applies.</para>
 446           </listitem>
 447         </varlistentry>
 448         <varlistentry>
 449           <term><varname>ReorderHeader=</varname></term>
 450           <listitem>
 451             <para>The VLAN reorder header is set VLAN interfaces behave like physical interfaces.
 452             A boolean. When unset, the kernel's default setting applies.</para>
 453           </listitem>
 454         </varlistentry>
 455       </variablelist>
 456   </refsect1>
 457
 458   <refsect1>
 459     <title>[MACVLAN] Section Options</title>
 460
 461     <para>The <literal>[MACVLAN]</literal> section only applies for
 462     netdevs of kind <literal>macvlan</literal>, and accepts the
 463     following key:</para>
 464
 465     <variablelist class='network-directives'>
 466       <varlistentry>
 467         <term><varname>Mode=</varname></term>
 468         <listitem>
 469           <para>The MACVLAN mode to use. The supported options are
 470           <literal>private</literal>,
 471           <literal>vepa</literal>,
 472           <literal>bridge</literal>, and
 473           <literal>passthru</literal>.
 474           </para>
 475         </listitem>
 476       </varlistentry>
 477     </variablelist>
 478
 479   </refsect1>
 480
 481     <refsect1>
 482     <title>[MACVTAP] Section Options</title>
 483
 484     <para>The <literal>[MACVTAP]</literal> section applies for
 485     netdevs of kind <literal>macvtap</literal> and accepts the
 486     same key as <literal>[MACVLAN]</literal>.</para>
 487
 488     </refsect1>
 489
 490   <refsect1>
 491     <title>[IPVLAN] Section Options</title>
 492
 493     <para>The <literal>[IPVLAN]</literal> section only applies for
 494     netdevs of kind <literal>ipvlan</literal>, and accepts the
 495     following key:</para>
 496
 497     <variablelist class='network-directives'>
 498       <varlistentry>
 499         <term><varname>Mode=</varname></term>
 500           <listitem>
 501             <para>The IPVLAN mode to use. The supported options are
 502             <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 503             </para>
 504           </listitem>
 505       </varlistentry>
 506        <varlistentry>
 507         <term><varname>Flags=</varname></term>
 508           <listitem>
 509             <para>The IPVLAN flags to use. The supported options are
 510             <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 511             </para>
 512           </listitem>
 513       </varlistentry>
 514     </variablelist>
 515
 516   </refsect1>
 517
 518   <refsect1>
 519     <title>[VXLAN] Section Options</title>
 520     <para>The <literal>[VXLAN]</literal> section only applies for
 521     netdevs of kind <literal>vxlan</literal>, and accepts the
 522     following keys:</para>
 523
 524     <variablelist class='network-directives'>
 525       <varlistentry>
 526         <term><varname>Id=</varname></term>
 527         <listitem>
 528           <para>The VXLAN ID to use.</para>
 529         </listitem>
 530       </varlistentry>
 531       <varlistentry>
 532         <term><varname>Remote=</varname></term>
 533         <listitem>
 534           <para>Configures destination IP address.</para>
 535         </listitem>
 536       </varlistentry>
 537       <varlistentry>
 538         <term><varname>Local=</varname></term>
 539         <listitem>
 540           <para>Configures local IP address.</para>
 541         </listitem>
 542       </varlistentry>
 543         <varlistentry>
 544         <term><varname>TOS=</varname></term>
 545         <listitem>
 546           <para>The Type Of Service byte value for a vxlan interface.</para>
 547         </listitem>
 548       </varlistentry>
 549       <varlistentry>
 550         <term><varname>TTL=</varname></term>
 551         <listitem>
 552           <para>A fixed Time To Live N on Virtual eXtensible Local
 553           Area Network packets. N is a number in the range 1–255. 0
 554           is a special value meaning that packets inherit the TTL
 555           value.</para>
 556         </listitem>
 557       </varlistentry>
 558       <varlistentry>
 559         <term><varname>MacLearning=</varname></term>
 560         <listitem>
 561           <para>A boolean. When true, enables dynamic MAC learning
 562           to discover remote MAC addresses.</para>
 563         </listitem>
 564       </varlistentry>
 565       <varlistentry>
 566         <term><varname>FDBAgeingSec=</varname></term>
 567         <listitem>
 568           <para>The lifetime of Forwarding Database entry learnt by
 569           the kernel, in seconds.</para>
 570         </listitem>
 571       </varlistentry>
 572       <varlistentry>
 573         <term><varname>MaximumFDBEntries=</varname></term>
 574         <listitem>
 575           <para>Configures maximum number of FDB entries.</para>
 576         </listitem>
 577       </varlistentry>
 578       <varlistentry>
 579         <term><varname>ReduceARPProxy=</varname></term>
 580         <listitem>
 581           <para>A boolean. When true, bridge-connected VXLAN tunnel
 582           endpoint answers ARP requests from the local bridge on behalf
 583           of remote Distributed Overlay Virtual Ethernet
 584           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 585           (DVOE)</ulink> clients. Defaults to false.</para>
 586         </listitem>
 587       </varlistentry>
 588       <varlistentry>
 589         <term><varname>L2MissNotification=</varname></term>
 590         <listitem>
 591           <para>A boolean. When true, enables netlink LLADDR miss
 592           notifications.</para>
 593         </listitem>
 594       </varlistentry>
 595       <varlistentry>
 596         <term><varname>L3MissNotification=</varname></term>
 597         <listitem>
 598           <para>A boolean. When true, enables netlink IP address miss
 599           notifications.</para>
 600         </listitem>
 601       </varlistentry>
 602       <varlistentry>
 603         <term><varname>RouteShortCircuit=</varname></term>
 604         <listitem>
 605           <para>A boolean. When true, route short circuiting is turned
 606           on.</para>
 607         </listitem>
 608       </varlistentry>
 609       <varlistentry>
 610         <term><varname>UDPChecksum=</varname></term>
 611         <listitem>
 612           <para>A boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 613         </listitem>
 614       </varlistentry>
 615       <varlistentry>
 616         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 617         <listitem>
 618           <para>A boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 619         </listitem>
 620       </varlistentry>
 621       <varlistentry>
 622         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 623         <listitem>
 624           <para>A boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 625         </listitem>
 626       </varlistentry>
 627       <varlistentry>
 628         <term><varname>RemoteChecksumTx=</varname></term>
 629         <listitem>
 630           <para>A boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 631         </listitem>
 632       </varlistentry>
 633       <varlistentry>
 634         <term><varname>RemoteChecksumRx=</varname></term>
 635         <listitem>
 636           <para>A boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 637         </listitem>
 638       </varlistentry>
 639     <varlistentry>
 640       <term><varname>GroupPolicyExtension=</varname></term>
 641       <listitem>
 642         <para>A boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 643         across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 644         <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 645         VXLAN Group Policy </ulink> document. Defaults to false.</para>
 646       </listitem>
 647     </varlistentry>
 648     <varlistentry>
 649       <term><varname>DestinationPort=</varname></term>
 650       <listitem>
 651         <para>Configures the default destination UDP port on a per-device basis.
 652         If destination port is not specified then Linux kernel default will be used.
 653         Set destination port 4789 to get the IANA assigned value. If not set or if the
 654         destination port is assigned the empty string the default port of 4789 is used.</para>
 655       </listitem>
 656     </varlistentry>
 657     <varlistentry>
 658       <term><varname>PortRange=</varname></term>
 659         <listitem>
 660           <para>Configures VXLAN port range. VXLAN bases source
 661           UDP port based on flow to help the receiver to be able
 662           to load balance based on outer header flow. It
 663           restricts the port range to the normal UDP local
 664           ports, and allows overriding via configuration.</para>
 665         </listitem>
 666       </varlistentry>
 667     <varlistentry>
 668       <term><varname>FlowLabel=</varname></term>
 669         <listitem>
 670           <para>Specifies the flow label to use in outgoing packets.
 671           The valid range is 0-1048575.
 672           </para>
 673         </listitem>
 674       </varlistentry>
 675     </variablelist>
 676   </refsect1>
 677   <refsect1>
 678     <title>[GENEVE] Section Options</title>
 679     <para>The <literal>[GENEVE]</literal> section only applies for
 680     netdevs of kind <literal>geneve</literal>, and accepts the
 681     following keys:</para>
 682
 683     <variablelist class='network-directives'>
 684       <varlistentry>
 685         <term><varname>Id=</varname></term>
 686         <listitem>
 687           <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [0-16777215].</para>
 688         </listitem>
 689       </varlistentry>
 690       <varlistentry>
 691         <term><varname>Remote=</varname></term>
 692         <listitem>
 693           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 694         </listitem>
 695       </varlistentry>
 696       <varlistentry>
 697         <term><varname>TOS=</varname></term>
 698         <listitem>
 699           <para>Specifies the TOS value to use in outgoing packets. Ranges [1-255].</para>
 700         </listitem>
 701       </varlistentry>
 702       <varlistentry>
 703         <term><varname>TTL=</varname></term>
 704         <listitem>
 705           <para>Specifies the TTL value to use in outgoing packets. Ranges [1-255].</para>
 706         </listitem>
 707       </varlistentry>
 708       <varlistentry>
 709         <term><varname>UDPChecksum=</varname></term>
 710         <listitem>
 711           <para>A boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.</para>
 712         </listitem>
 713       </varlistentry>
 714       <varlistentry>
 715         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 716         <listitem>
 717           <para>A boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 718         </listitem>
 719       </varlistentry>
 720       <varlistentry>
 721         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 722         <listitem>
 723           <para>A boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 724         </listitem>
 725       </varlistentry>
 726     <varlistentry>
 727       <term><varname>DestinationPort=</varname></term>
 728       <listitem>
 729         <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 730         port of 6081 is used.</para>
 731       </listitem>
 732     </varlistentry>
 733     <varlistentry>
 734       <term><varname>FlowLabel=</varname></term>
 735         <listitem>
 736           <para>Specifies the flow label to use in outgoing packets.</para>
 737         </listitem>
 738       </varlistentry>
 739     </variablelist>
 740   </refsect1>
 741   <refsect1>
 742     <title>[Tunnel] Section Options</title>
 743
 744     <para>The <literal>[Tunnel]</literal> section only applies for
 745     netdevs of kind
 746     <literal>ipip</literal>,
 747     <literal>sit</literal>,
 748     <literal>gre</literal>,
 749     <literal>gretap</literal>,
 750     <literal>ip6gre</literal>,
 751     <literal>ip6gretap</literal>,
 752     <literal>vti</literal>,
 753     <literal>vti6</literal>, and
 754     <literal>ip6tnl</literal> and accepts
 755     the following keys:</para>
 756
 757     <variablelist class='network-directives'>
 758       <varlistentry>
 759         <term><varname>Local=</varname></term>
 760         <listitem>
 761           <para>A static local address for tunneled packets. It must
 762           be an address on another interface of this host.</para>
 763         </listitem>
 764       </varlistentry>
 765       <varlistentry>
 766         <term><varname>Remote=</varname></term>
 767         <listitem>
 768           <para>The remote endpoint of the tunnel.</para>
 769         </listitem>
 770       </varlistentry>
 771       <varlistentry>
 772         <term><varname>TOS=</varname></term>
 773         <listitem>
 774           <para>The Type Of Service byte value for a tunnel interface.
 775           For details about the TOS, see the
 776           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
 777           Service in the Internet Protocol Suite </ulink> document.
 778           </para>
 779         </listitem>
 780       </varlistentry>
 781       <varlistentry>
 782         <term><varname>TTL=</varname></term>
 783         <listitem>
 784           <para>A fixed Time To Live N on tunneled packets. N is a
 785           number in the range 1–255. 0 is a special value meaning that
 786           packets inherit the TTL value. The default value for IPv4
 787           tunnels is: inherit. The default value for IPv6 tunnels is
 788           64.</para>
 789         </listitem>
 790       </varlistentry>
 791       <varlistentry>
 792         <term><varname>DiscoverPathMTU=</varname></term>
 793         <listitem>
 794           <para>A boolean. When true, enables Path MTU Discovery on
 795           the tunnel.</para>
 796         </listitem>
 797       </varlistentry>
 798       <varlistentry>
 799         <term><varname>IPv6FlowLabel=</varname></term>
 800         <listitem>
 801           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
 802           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
 803           RFC 2460</ulink>), which is used by a node to label packets of a flow.
 804           It is only used for IPv6 tunnels.
 805           A flow label of zero is used to indicate packets that have
 806           not been labeled.
 807           It can be configured to a value in the range 0–0xFFFFF, or be
 808           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
 809         </listitem>
 810       </varlistentry>
 811       <varlistentry>
 812         <term><varname>CopyDSCP=</varname></term>
 813         <listitem>
 814           <para>A boolean. When true, the Differentiated Service Code
 815           Point (DSCP) field will be copied to the inner header from
 816           outer header during the decapsulation of an IPv6 tunnel
 817           packet. DSCP is a field in an IP packet that enables different
 818           levels of service to be assigned to network traffic.
 819           Defaults to <literal>no</literal>.
 820           </para>
 821         </listitem>
 822       </varlistentry>
 823       <varlistentry>
 824         <term><varname>EncapsulationLimit=</varname></term>
 825         <listitem>
 826           <para>The Tunnel Encapsulation Limit option specifies how many additional
 827           levels of encapsulation are permitted to be prepended to the packet.
 828           For example, a Tunnel Encapsulation Limit option containing a limit
 829           value of zero means that a packet carrying that option may not enter
 830           another tunnel before exiting the current tunnel.
 831           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
 832           The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
 833         </para>
 834         </listitem>
 835       </varlistentry>
 836       <varlistentry>
 837         <term><varname>Key=</varname></term>
 838         <listitem>
 839           <para>The <varname>Key=</varname> parameter specifies the same key to use in
 840           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
 841           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
 842           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
 843           and control path) in ip xfrm (framework used to implement IPsec protocol).
 844           See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
 845           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6
 846           tunnels.</para>
 847         </listitem>
 848       </varlistentry>
 849       <varlistentry>
 850         <term><varname>InputKey=</varname></term>
 851         <listitem>
 852           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
 853           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
 854         </listitem>
 855       </varlistentry>
 856       <varlistentry>
 857         <term><varname>OutputKey=</varname></term>
 858         <listitem>
 859           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
 860           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
 861         </listitem>
 862       </varlistentry>
 863       <varlistentry>
 864         <term><varname>Mode=</varname></term>
 865         <listitem>
 866           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
 867           modes
 868           <literal>ip6ip6</literal> for IPv6 over IPv6,
 869           <literal>ipip6</literal> for IPv4 over IPv6 or
 870           <literal>any</literal> for either.
 871           </para>
 872         </listitem>
 873       </varlistentry>
 874       <varlistentry>
 875         <term><varname>Independent=</varname></term>
 876         <listitem>
 877           <para>A boolean. When true tunnel does not require .network file. Created as "tunnel@NONE".
 878           Defaults to <literal>false</literal>.
 879           </para>
 880         </listitem>
 881       </varlistentry>
 882       <varlistentry>
 883         <term><varname>AllowLocalRemote=</varname></term>
 884         <listitem>
 885           <para>A boolean. When true allows tunnel traffic on <varname>ip6tnl</varname> devices where the remote endpoint is a local host address.
 886           Defaults to unset.
 887           </para>
 888         </listitem>
 889       </varlistentry>
 890     </variablelist>
 891   </refsect1>
 892   <refsect1>
 893     <title>[Peer] Section Options</title>
 894
 895       <para>The <literal>[Peer]</literal> section only applies for
 896       netdevs of kind <literal>veth</literal> and accepts the
 897       following keys:</para>
 898
 899       <variablelist class='network-directives'>
 900         <varlistentry>
 901           <term><varname>Name=</varname></term>
 902           <listitem>
 903             <para>The interface name used when creating the netdev.
 904             This option is compulsory.</para>
 905           </listitem>
 906         </varlistentry>
 907         <varlistentry>
 908           <term><varname>MACAddress=</varname></term>
 909           <listitem>
 910             <para>The peer MACAddress, if not set, it is generated in
 911             the same way as the MAC address of the main
 912             interface.</para>
 913           </listitem>
 914         </varlistentry>
 915       </variablelist>
 916   </refsect1>
 917   <refsect1>
 918   <title>[VXCAN] Section Options</title>
 919       <para>The <literal>[VXCAN]</literal> section only applies for
 920       netdevs of kind <literal>vxcan</literal> and accepts the
 921       following key:</para>
 922
 923       <variablelist class='network-directives'>
 924         <varlistentry>
 925           <term><varname>Peer=</varname></term>
 926           <listitem>
 927             <para>The peer interface name used when creating the netdev.
 928             This option is compulsory.</para>
 929           </listitem>
 930         </varlistentry>
 931       </variablelist>
 932   </refsect1>
 933   <refsect1>
 934     <title>[Tun] Section Options</title>
 935
 936     <para>The <literal>[Tun]</literal> section only applies for
 937     netdevs of kind <literal>tun</literal>, and accepts the following
 938     keys:</para>
 939
 940     <variablelist class='network-directives'>
 941       <varlistentry>
 942         <term><varname>OneQueue=</varname></term>
 943         <listitem><para>Takes a boolean argument. Configures whether
 944         all packets are queued at the device (enabled), or a fixed
 945         number of packets are queued at the device and the rest at the
 946         <literal>qdisc</literal>. Defaults to
 947         <literal>no</literal>.</para>
 948         </listitem>
 949       </varlistentry>
 950       <varlistentry>
 951         <term><varname>MultiQueue=</varname></term>
 952         <listitem><para>Takes a boolean argument. Configures whether
 953         to use multiple file descriptors (queues) to parallelize
 954         packets sending and receiving. Defaults to
 955         <literal>no</literal>.</para>
 956         </listitem>
 957       </varlistentry>
 958       <varlistentry>
 959         <term><varname>PacketInfo=</varname></term>
 960         <listitem><para>Takes a boolean argument. Configures whether
 961         packets should be prepended with four extra bytes (two flag
 962         bytes and two protocol bytes). If disabled, it indicates that
 963         the packets will be pure IP packets. Defaults to
 964         <literal>no</literal>.</para>
 965         </listitem>
 966       </varlistentry>
 967       <varlistentry>
 968         <term><varname>VNetHeader=</varname></term>
 969         <listitem><para>Takes a boolean argument. Configures
 970         IFF_VNET_HDR flag for a tap device. It allows sending
 971         and receiving larger Generic Segmentation Offload (GSO)
 972         packets. This may increase throughput significantly.
 973         Defaults to
 974         <literal>no</literal>.</para>
 975         </listitem>
 976       </varlistentry>
 977       <varlistentry>
 978         <term><varname>User=</varname></term>
 979         <listitem><para>User to grant access to the
 980         <filename>/dev/net/tun</filename> device.</para>
 981         </listitem>
 982       </varlistentry>
 983       <varlistentry>
 984         <term><varname>Group=</varname></term>
 985         <listitem><para>Group to grant access to the
 986         <filename>/dev/net/tun</filename> device.</para>
 987         </listitem>
 988       </varlistentry>
 989
 990     </variablelist>
 991
 992   </refsect1>
 993
 994   <refsect1>
 995     <title>[Tap] Section Options</title>
 996
 997     <para>The <literal>[Tap]</literal> section only applies for
 998     netdevs of kind <literal>tap</literal>, and accepts the same keys
 999     as the <literal>[Tun]</literal> section.</para>
1000   </refsect1>
1001
1002   <refsect1>
1003     <title>[WireGuard] Section Options</title>
1004
1005     <para>The <literal>[WireGuard]</literal> section accepts the following
1006     keys:</para>
1007
1008     <variablelist class='network-directives'>
1009       <varlistentry>
1010         <term><varname>PrivateKey=</varname></term>
1011         <listitem>
1012           <para>The Base64 encoded private key for the interface. It can be
1013             generated using the <command>wg genkey</command> command
1014             (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1015             This option is mandatory to use WireGuard.
1016             Note that because this information is secret, you may want to set
1017             the permissions of the .netdev file to be owned by <literal>root:systemd-networkd</literal>
1018             with a <literal>0640</literal> file mode.</para>
1019         </listitem>
1020       </varlistentry>
1021       <varlistentry>
1022         <term><varname>ListenPort=</varname></term>
1023         <listitem>
1024           <para>Sets UDP port for listening. Takes either value between 1 and 65535
1025             or <literal>auto</literal>. If <literal>auto</literal> is specified,
1026             the port is automatically generated based on interface name.
1027             Defaults to <literal>auto</literal>.</para>
1028         </listitem>
1029       </varlistentry>
1030       <varlistentry>
1031         <term><varname>FwMark=</varname></term>
1032         <listitem>
1033           <para>Sets a firewall mark on outgoing WireGuard packets from this interface.</para>
1034         </listitem>
1035       </varlistentry>
1036     </variablelist>
1037   </refsect1>
1038
1039   <refsect1>
1040     <title>[WireGuardPeer] Section Options</title>
1041
1042     <para>The <literal>[WireGuardPeer]</literal> section accepts the following
1043     keys:</para>
1044
1045     <variablelist class='network-directives'>
1046       <varlistentry>
1047         <term><varname>PublicKey=</varname></term>
1048         <listitem>
1049           <para>Sets a Base64 encoded public key calculated by <command>wg pubkey</command>
1050             (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1051             from a private key, and usually transmitted out of band to the
1052             author of the configuration file. This option is mandatory for this
1053             section.</para>
1054         </listitem>
1055       </varlistentry>
1056       <varlistentry>
1057         <term><varname>PresharedKey=</varname></term>
1058         <listitem>
1059           <para>Optional preshared key for the interface. It can be generated
1060             by the <command>wg genpsk</command> command. This option adds an
1061             additional layer of symmetric-key cryptography to be mixed into the
1062             already existing public-key cryptography, for post-quantum
1063             resistance.
1064             Note that because this information is secret, you may want to set
1065             the permissions of the .netdev file to be owned by <literal>root:systemd-networkd</literal>
1066             with a <literal>0640</literal> file mode.</para>
1067         </listitem>
1068       </varlistentry>
1069       <varlistentry>
1070         <term><varname>AllowedIPs=</varname></term>
1071         <listitem>
1072           <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks
1073             from which this peer is allowed to send incoming traffic and to
1074             which outgoing traffic for this peer is directed. The catch-all
1075             0.0.0.0/0 may be specified for matching all IPv4 addresses, and
1076             ::/0 may be specified for matching all IPv6 addresses. </para>
1077         </listitem>
1078       </varlistentry>
1079       <varlistentry>
1080         <term><varname>Endpoint=</varname></term>
1081         <listitem>
1082           <para>Sets an endpoint IP address or hostname, followed by a colon, and then
1083             a port number. This endpoint will be updated automatically once to
1084             the most recent source IP address and port of correctly
1085             authenticated packets from the peer at configuration time.</para>
1086         </listitem>
1087       </varlistentry>
1088       <varlistentry>
1089         <term><varname>PersistentKeepalive=</varname></term>
1090         <listitem>
1091           <para>Sets a seconds interval, between 1 and 65535 inclusive, of how often
1092             to send an authenticated empty packet to the peer for the purpose
1093             of keeping a stateful firewall or NAT mapping valid persistently.
1094             For example, if the interface very rarely sends traffic, but it
1095             might at anytime receive traffic from a peer, and it is behind NAT,
1096             the interface might benefit from having a persistent keepalive
1097             interval of 25 seconds. If set to 0 or "off", this option is
1098             disabled. By default or when unspecified, this option is off.
1099             Most users will not need this.</para>
1100         </listitem>
1101       </varlistentry>
1102     </variablelist>
1103   </refsect1>
1104
1105   <refsect1>
1106     <title>[Bond] Section Options</title>
1107
1108     <para>The <literal>[Bond]</literal> section accepts the following
1109     key:</para>
1110
1111     <variablelist class='network-directives'>
1112       <varlistentry>
1113         <term><varname>Mode=</varname></term>
1114         <listitem>
1115           <para>Specifies one of the bonding policies. The default is
1116           <literal>balance-rr</literal> (round robin). Possible values are
1117           <literal>balance-rr</literal>,
1118           <literal>active-backup</literal>,
1119           <literal>balance-xor</literal>,
1120           <literal>broadcast</literal>,
1121           <literal>802.3ad</literal>,
1122           <literal>balance-tlb</literal>, and
1123           <literal>balance-alb</literal>.
1124           </para>
1125         </listitem>
1126       </varlistentry>
1127
1128       <varlistentry>
1129         <term><varname>TransmitHashPolicy=</varname></term>
1130         <listitem>
1131           <para>Selects the transmit hash policy to use for slave
1132           selection in balance-xor, 802.3ad, and tlb modes. Possible
1133           values are
1134           <literal>layer2</literal>,
1135           <literal>layer3+4</literal>,
1136           <literal>layer2+3</literal>,
1137           <literal>encap2+3</literal>, and
1138           <literal>encap3+4</literal>.
1139           </para>
1140         </listitem>
1141       </varlistentry>
1142
1143       <varlistentry>
1144         <term><varname>LACPTransmitRate=</varname></term>
1145         <listitem>
1146           <para>Specifies the rate with which link partner transmits
1147           Link Aggregation Control Protocol Data Unit packets in
1148           802.3ad mode. Possible values are <literal>slow</literal>,
1149           which requests partner to transmit LACPDUs every 30 seconds,
1150           and <literal>fast</literal>, which requests partner to
1151           transmit LACPDUs every second. The default value is
1152           <literal>slow</literal>.</para>
1153         </listitem>
1154       </varlistentry>
1155
1156       <varlistentry>
1157         <term><varname>MIIMonitorSec=</varname></term>
1158         <listitem>
1159           <para>Specifies the frequency that Media Independent
1160           Interface link monitoring will occur. A value of zero
1161           disables MII link monitoring. This value is rounded down to
1162           the nearest millisecond. The default value is 0.</para>
1163         </listitem>
1164       </varlistentry>
1165
1166       <varlistentry>
1167         <term><varname>UpDelaySec=</varname></term>
1168         <listitem>
1169           <para>Specifies the delay before a link is enabled after a
1170           link up status has been detected. This value is rounded down
1171           to a multiple of MIIMonitorSec. The default value is
1172           0.</para>
1173         </listitem>
1174       </varlistentry>
1175
1176       <varlistentry>
1177         <term><varname>DownDelaySec=</varname></term>
1178         <listitem>
1179           <para>Specifies the delay before a link is disabled after a
1180           link down status has been detected. This value is rounded
1181           down to a multiple of MIIMonitorSec. The default value is
1182           0.</para>
1183         </listitem>
1184       </varlistentry>
1185
1186       <varlistentry>
1187         <term><varname>LearnPacketIntervalSec=</varname></term>
1188         <listitem>
1189           <para>Specifies the number of seconds between instances where the bonding
1190           driver sends learning packets to each slave peer switch.
1191           The valid range is 1–0x7fffffff; the default value is 1. This option
1192           has an effect only for the balance-tlb and balance-alb modes.</para>
1193         </listitem>
1194       </varlistentry>
1195
1196       <varlistentry>
1197         <term><varname>AdSelect=</varname></term>
1198         <listitem>
1199           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
1200           <literal>stable</literal>,
1201           <literal>bandwidth</literal> and
1202           <literal>count</literal>.
1203           </para>
1204         </listitem>
1205       </varlistentry>
1206
1207       <varlistentry>
1208         <term><varname>FailOverMACPolicy=</varname></term>
1209         <listitem>
1210           <para>Specifies whether the active-backup mode should set all slaves to
1211           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1212           bond's MAC address in accordance with the selected policy. The default policy is none.
1213           Possible values are
1214           <literal>none</literal>,
1215           <literal>active</literal> and
1216           <literal>follow</literal>.
1217           </para>
1218         </listitem>
1219       </varlistentry>
1220
1221       <varlistentry>
1222         <term><varname>ARPValidate=</varname></term>
1223         <listitem>
1224           <para>Specifies whether or not ARP probes and replies should be
1225           validated in any mode that supports ARP monitoring, or whether
1226           non-ARP traffic should be filtered (disregarded) for link
1227           monitoring purposes. Possible values are
1228           <literal>none</literal>,
1229           <literal>active</literal>,
1230           <literal>backup</literal> and
1231           <literal>all</literal>.
1232           </para>
1233         </listitem>
1234       </varlistentry>
1235
1236       <varlistentry>
1237         <term><varname>ARPIntervalSec=</varname></term>
1238         <listitem>
1239           <para>Specifies the ARP link monitoring frequency in milliseconds.
1240           A value of 0 disables ARP monitoring. The default value is 0.
1241           </para>
1242         </listitem>
1243       </varlistentry>
1244
1245       <varlistentry>
1246         <term><varname>ARPIPTargets=</varname></term>
1247         <listitem>
1248           <para>Specifies the IP addresses to use as ARP monitoring peers when
1249           ARPIntervalSec is greater than 0. These are the targets of the ARP request
1250           sent to determine the health of the link to the targets.
1251           Specify these values in IPv4 dotted decimal format. At least one IP
1252           address must be given for ARP monitoring to function. The
1253           maximum number of targets that can be specified is 16. The
1254           default value is no IP addresses.
1255           </para>
1256         </listitem>
1257       </varlistentry>
1258
1259       <varlistentry>
1260         <term><varname>ARPAllTargets=</varname></term>
1261         <listitem>
1262           <para>Specifies the quantity of ARPIPTargets that must be reachable
1263           in order for the ARP monitor to consider a slave as being up.
1264           This option affects only active-backup mode for slaves with
1265           ARPValidate enabled. Possible values are
1266           <literal>any</literal> and
1267           <literal>all</literal>.
1268           </para>
1269         </listitem>
1270       </varlistentry>
1271
1272       <varlistentry>
1273         <term><varname>PrimaryReselectPolicy=</varname></term>
1274         <listitem>
1275           <para>Specifies the reselection policy for the primary slave.  This
1276           affects how the primary slave is chosen to become the active slave
1277           when failure of the active slave or recovery of the primary slave
1278           occurs. This option is designed to prevent flip-flopping between
1279           the primary slave and other slaves.  Possible values are
1280           <literal>always</literal>,
1281           <literal>better</literal> and
1282           <literal>failure</literal>.
1283           </para>
1284         </listitem>
1285       </varlistentry>
1286
1287       <varlistentry>
1288         <term><varname>ResendIGMP=</varname></term>
1289         <listitem>
1290           <para>Specifies the number of IGMP membership reports to be issued after
1291           a failover event. One membership report is issued immediately after
1292           the failover, subsequent packets are sent in each 200ms interval.
1293           The valid range is 0–255. Defaults to 1. A value of 0
1294           prevents the IGMP membership report from being issued in response
1295           to the failover event.
1296           </para>
1297         </listitem>
1298       </varlistentry>
1299
1300       <varlistentry>
1301         <term><varname>PacketsPerSlave=</varname></term>
1302         <listitem>
1303           <para>Specify the number of packets to transmit through a slave before
1304             moving to the next one. When set to 0, then a slave is chosen at
1305             random. The valid range is 0–65535. Defaults to 1. This option
1306             only has effect when in balance-rr mode.
1307           </para>
1308         </listitem>
1309       </varlistentry>
1310
1311       <varlistentry>
1312         <term><varname>GratuitousARP=</varname></term>
1313         <listitem>
1314           <para>Specify the number of peer notifications (gratuitous ARPs and
1315             unsolicited IPv6 Neighbor Advertisements) to be issued after a
1316             failover event.  As soon as the link is up on the new slave,
1317             a peer notification is sent on the  bonding device and each
1318             VLAN sub-device.  This is repeated at each link monitor interval
1319             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1320             greater than 1. The valid range is 0–255. The default value is 1.
1321             These options affect only the active-backup mode.
1322           </para>
1323         </listitem>
1324       </varlistentry>
1325
1326       <varlistentry>
1327         <term><varname>AllSlavesActive=</varname></term>
1328         <listitem>
1329           <para>A boolean. Specifies that duplicate frames (received on inactive ports)
1330           should be dropped when false, or delivered when true. Normally, bonding will drop
1331           duplicate frames (received on inactive ports), which is desirable for
1332           most users. But there are some times it is nice to allow duplicate
1333           frames to be delivered. The default value is false (drop duplicate frames
1334           received on inactive ports).
1335           </para>
1336         </listitem>
1337       </varlistentry>
1338
1339       <varlistentry>
1340         <term><varname>MinLinks=</varname></term>
1341         <listitem>
1342           <para>Specifies the minimum number of links that must be active before
1343           asserting carrier. The default value is 0.
1344           </para>
1345         </listitem>
1346       </varlistentry>
1347     </variablelist>
1348
1349     <para>For more detail information see
1350     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1351     Linux Ethernet Bonding Driver HOWTO</ulink></para>
1352
1353   </refsect1>
1354
1355   <refsect1>
1356     <title>Example</title>
1357     <example>
1358       <title>/etc/systemd/network/25-bridge.netdev</title>
1359
1360       <programlisting>[NetDev]
1361 Name=bridge0
1362 Kind=bridge</programlisting>
1363     </example>
1364
1365     <example>
1366       <title>/etc/systemd/network/25-vlan1.netdev</title>
1367
1368       <programlisting>[Match]
1369 Virtualization=no
1370
1371 [NetDev]
1372 Name=vlan1
1373 Kind=vlan
1374
1375 [VLAN]
1376 Id=1</programlisting>
1377     </example>
1378     <example>
1379       <title>/etc/systemd/network/25-ipip.netdev</title>
1380       <programlisting>[NetDev]
1381 Name=ipip-tun
1382 Kind=ipip
1383 MTUBytes=1480
1384
1385 [Tunnel]
1386 Local=192.168.223.238
1387 Remote=192.169.224.239
1388 TTL=64</programlisting>
1389     </example>
1390     <example>
1391       <title>/etc/systemd/network/25-tap.netdev</title>
1392       <programlisting>[NetDev]
1393 Name=tap-test
1394 Kind=tap
1395
1396 [Tap]
1397 MultiQueue=true
1398 PacketInfo=true</programlisting> </example>
1399
1400     <example>
1401       <title>/etc/systemd/network/25-sit.netdev</title>
1402       <programlisting>[NetDev]
1403 Name=sit-tun
1404 Kind=sit
1405 MTUBytes=1480
1406
1407 [Tunnel]
1408 Local=10.65.223.238
1409 Remote=10.65.223.239</programlisting>
1410     </example>
1411
1412     <example>
1413       <title>/etc/systemd/network/25-gre.netdev</title>
1414       <programlisting>[NetDev]
1415 Name=gre-tun
1416 Kind=gre
1417 MTUBytes=1480
1418
1419 [Tunnel]
1420 Local=10.65.223.238
1421 Remote=10.65.223.239</programlisting>
1422     </example>
1423
1424     <example>
1425       <title>/etc/systemd/network/25-vti.netdev</title>
1426
1427       <programlisting>[NetDev]
1428 Name=vti-tun
1429 Kind=vti
1430 MTUBytes=1480
1431
1432 [Tunnel]
1433 Local=10.65.223.238
1434 Remote=10.65.223.239</programlisting>
1435     </example>
1436
1437     <example>
1438       <title>/etc/systemd/network/25-veth.netdev</title>
1439       <programlisting>[NetDev]
1440 Name=veth-test
1441 Kind=veth
1442
1443 [Peer]
1444 Name=veth-peer</programlisting>
1445     </example>
1446
1447     <example>
1448       <title>/etc/systemd/network/25-bond.netdev</title>
1449       <programlisting>[NetDev]
1450 Name=bond1
1451 Kind=bond
1452
1453 [Bond]
1454 Mode=802.3ad
1455 TransmitHashPolicy=layer3+4
1456 MIIMonitorSec=1s
1457 LACPTransmitRate=fast
1458 </programlisting>
1459     </example>
1460
1461     <example>
1462       <title>/etc/systemd/network/25-dummy.netdev</title>
1463       <programlisting>[NetDev]
1464 Name=dummy-test
1465 Kind=dummy
1466 MACAddress=12:34:56:78:9a:bc</programlisting>
1467     </example>
1468     <example>
1469       <title>/etc/systemd/network/25-vrf.netdev</title>
1470       <para>Create a VRF interface with table 42.</para>
1471       <programlisting>[NetDev]
1472 Name=vrf-test
1473 Kind=vrf
1474
1475 [VRF]
1476 Table=42</programlisting>
1477     </example>
1478
1479     <example>
1480       <title>/etc/systemd/network/25-macvtap.netdev</title>
1481       <para>Create a MacVTap device.</para>
1482       <programlisting>[NetDev]
1483 Name=macvtap-test
1484 Kind=macvtap
1485       </programlisting>
1486     </example>
1487     <example>
1488       <title>/etc/systemd/network/25-wireguard.netdev</title>
1489       <programlisting>[NetDev]
1490 Name=wg0
1491 Kind=wireguard
1492
1493 [WireGuard]
1494 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
1495 ListenPort=51820
1496
1497 [WireGuardPeer]
1498 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
1499 AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
1500 Endpoint=wireguard.example.com:51820</programlisting>
1501     </example>
1502   </refsect1>
1503   <refsect1>
1504     <title>See Also</title>
1505     <para>
1506       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1507       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1508       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1509       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1510     </para>
1511   </refsect1>
1512
1513 </refentry>