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+ -->
   5
   6 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>
   7
   8   <refentryinfo>
   9     <title>systemd.network</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>systemd.netdev</refentrytitle>
  15     <manvolnum>5</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>systemd.netdev</refname>
  20     <refpurpose>Virtual Network Device configuration</refpurpose>
  21   </refnamediv>
  22
  23   <refsynopsisdiv>
  24     <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  25   </refsynopsisdiv>
  26
  27   <refsect1>
  28     <title>Description</title>
  29
  30     <para>Network setup is performed by
  31     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  32     </para>
  33
  34     <para>The main Virtual Network Device file must have the extension <filename>.netdev</filename>;
  35     other extensions are ignored. Virtual network devices are created as soon as networkd is
  36     started. If a netdev with the specified name already exists, networkd will use that as-is rather
  37     than create its own. Note that the settings of the pre-existing netdev will not be changed by
  38     networkd.</para>
  39
  40     <para>The <filename>.netdev</filename> files are read from the files located in the system
  41     network directory <filename>/usr/lib/systemd/network</filename>, the volatile runtime network
  42     directory <filename>/run/systemd/network</filename> and the local administration network
  43     directory <filename>/etc/systemd/network</filename>. All configuration files are collectively
  44     sorted and processed in lexical order, regardless of the directories in which they live.
  45     However, files with identical filenames replace each other. Files in <filename>/etc</filename>
  46     have the highest priority, files in <filename>/run</filename> take precedence over files with
  47     the same name in <filename>/usr/lib</filename>. This can be used to override a system-supplied
  48     configuration file with a local file if needed. As a special case, an empty file (file size 0)
  49     or symlink with the same name pointing to <filename>/dev/null</filename> disables the
  50     configuration file entirely (it is "masked").</para>
  51
  52     <para>Along with the netdev file <filename>foo.netdev</filename>, a "drop-in" directory
  53     <filename>foo.netdev.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  54     from this directory will be parsed after the file itself is parsed. This is useful to alter or
  55     add configuration settings, without having to modify the main configuration file. Each drop-in
  56     file must have appropriate section headers.</para>
  57
  58     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  59     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  60     <filename>/run/systemd/network</filename> directories. Drop-in files in
  61     <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
  62     take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
  63     directories take precedence over the main netdev file wherever located. (Of course, since
  64     <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is
  65     unlikely drop-ins should be used in either of those places.)</para>
  66   </refsect1>
  67
  68   <refsect1>
  69     <title>Supported netdev kinds</title>
  70
  71     <para>The following kinds of virtual network devices may be
  72     configured in <filename>.netdev</filename> files:</para>
  73
  74     <table>
  75       <title>Supported kinds of virtual network devices</title>
  76
  77       <tgroup cols='2'>
  78         <colspec colname='kind' />
  79         <colspec colname='explanation' />
  80         <thead><row>
  81           <entry>Kind</entry>
  82           <entry>Description</entry>
  83         </row></thead>
  84         <tbody>
  85           <row><entry><varname>bond</varname></entry>
  86           <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>
  87
  88           <row><entry><varname>bridge</varname></entry>
  89           <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>
  90
  91           <row><entry><varname>dummy</varname></entry>
  92           <entry>A dummy device drops all packets sent to it.</entry></row>
  93
  94           <row><entry><varname>gre</varname></entry>
  95           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
  96
  97           <row><entry><varname>gretap</varname></entry>
  98           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
  99
 100           <row><entry><varname>erspan</varname></entry>
 101           <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.</entry></row>
 102
 103           <row><entry><varname>ip6gre</varname></entry>
 104           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 105
 106           <row><entry><varname>ip6tnl</varname></entry>
 107           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 108
 109           <row><entry><varname>ip6gretap</varname></entry>
 110           <entry>A Level 2 GRE tunnel over IPv6.</entry></row>
 111
 112           <row><entry><varname>ipip</varname></entry>
 113           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 114
 115           <row><entry><varname>ipvlan</varname></entry>
 116           <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 117
 118           <row><entry><varname>ipvtap</varname></entry>
 119           <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>
 120
 121           <row><entry><varname>macvlan</varname></entry>
 122           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 123
 124           <row><entry><varname>macvtap</varname></entry>
 125           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 126
 127           <row><entry><varname>sit</varname></entry>
 128           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 129
 130           <row><entry><varname>tap</varname></entry>
 131           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 132
 133           <row><entry><varname>tun</varname></entry>
 134           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 135
 136           <row><entry><varname>veth</varname></entry>
 137           <entry>An Ethernet tunnel between a pair of network devices.</entry></row>
 138
 139           <row><entry><varname>vlan</varname></entry>
 140           <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>
 141
 142           <row><entry><varname>vti</varname></entry>
 143           <entry>An IPv4 over IPSec tunnel.</entry></row>
 144
 145           <row><entry><varname>vti6</varname></entry>
 146           <entry>An IPv6 over IPSec tunnel.</entry></row>
 147
 148           <row><entry><varname>vxlan</varname></entry>
 149           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 150
 151           <row><entry><varname>geneve</varname></entry>
 152           <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.</entry></row>
 153
 154           <row><entry><varname>l2tp</varname></entry>
 155           <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>
 156
 157           <row><entry><varname>macsec</varname></entry>
 158           <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>
 159
 160           <row><entry><varname>vrf</varname></entry>
 161           <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>
 162
 163           <row><entry><varname>vcan</varname></entry>
 164           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 165
 166           <row><entry><varname>vxcan</varname></entry>
 167           <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.
 168           </entry></row>
 169
 170           <row><entry><varname>wireguard</varname></entry>
 171           <entry>WireGuard Secure Network Tunnel.</entry></row>
 172
 173           <row><entry><varname>netdevsim</varname></entry>
 174           <entry>A simulator. This simulated networking device is used for testing various networking APIs and at this time is particularly focused on testing hardware offloading related interfaces.</entry></row>
 175
 176           <row><entry><varname>nlmon</varname></entry>
 177           <entry>A Netlink monitor device. Use an nlmon device when you want to monitor system Netlink messages.</entry></row>
 178
 179           <row><entry><varname>fou</varname></entry>
 180           <entry>Foo-over-UDP tunneling.</entry></row>
 181
 182         </tbody>
 183       </tgroup>
 184     </table>
 185
 186   </refsect1>
 187
 188   <refsect1>
 189     <title>[Match] Section Options</title>
 190
 191     <para>A virtual network device is only created if the
 192     <literal>[Match]</literal> section matches the current
 193     environment, or if the section is empty. The following keys are
 194     accepted:</para>
 195
 196     <variablelist class='network-directives'>
 197       <varlistentry>
 198         <term><varname>Host=</varname></term>
 199         <listitem>
 200           <para>Matches against the hostname or machine ID of the host. See
 201           <literal>ConditionHost=</literal> in
 202           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 203           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 204           If an empty string is assigned, then previously assigned value is cleared.
 205           </para>
 206         </listitem>
 207       </varlistentry>
 208       <varlistentry>
 209         <term><varname>Virtualization=</varname></term>
 210         <listitem>
 211           <para>Checks whether the system is executed in a virtualized environment and optionally test
 212           whether it is a specific implementation. See <literal>ConditionVirtualization=</literal> in
 213           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 214           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 215           If an empty string is assigned, then previously assigned value is cleared.
 216           </para>
 217         </listitem>
 218       </varlistentry>
 219       <varlistentry>
 220         <term><varname>KernelCommandLine=</varname></term>
 221         <listitem>
 222           <para>Checks whether a specific kernel command line option is set. See
 223           <literal>ConditionKernelCommandLine=</literal> in
 224           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 225           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 226           If an empty string is assigned, then previously assigned value is cleared.
 227           </para>
 228         </listitem>
 229       </varlistentry>
 230       <varlistentry>
 231         <term><varname>KernelVersion=</varname></term>
 232         <listitem>
 233           <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a
 234           certain expression. See <literal>ConditionKernelVersion=</literal> in
 235           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 236           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 237           If an empty string is assigned, then previously assigned value is cleared.
 238           </para>
 239         </listitem>
 240       </varlistentry>
 241       <varlistentry>
 242         <term><varname>Architecture=</varname></term>
 243         <listitem>
 244           <para>Checks whether the system is running on a specific architecture. See
 245           <literal>ConditionArchitecture=</literal> in
 246           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 247           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 248           If an empty string is assigned, then previously assigned value is cleared.
 249           </para>
 250         </listitem>
 251       </varlistentry>
 252     </variablelist>
 253
 254   </refsect1>
 255
 256   <refsect1>
 257     <title>[NetDev] Section Options</title>
 258
 259       <para>The <literal>[NetDev]</literal> section accepts the
 260       following keys:</para>
 261
 262       <variablelist class='network-directives'>
 263         <varlistentry>
 264           <term><varname>Description=</varname></term>
 265           <listitem>
 266             <para>A free-form description of the netdev.</para>
 267           </listitem>
 268         </varlistentry>
 269         <varlistentry>
 270           <term><varname>Name=</varname></term>
 271           <listitem>
 272             <para>The interface name used when creating the netdev.
 273             This option is compulsory.</para>
 274           </listitem>
 275         </varlistentry>
 276         <varlistentry>
 277           <term><varname>Kind=</varname></term>
 278           <listitem>
 279             <para>The netdev kind. This option is compulsory. See the
 280             <literal>Supported netdev kinds</literal> section for the
 281             valid keys.</para>
 282           </listitem>
 283         </varlistentry>
 284         <varlistentry>
 285           <term><varname>MTUBytes=</varname></term>
 286           <listitem>
 287             <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M, G,
 288             are supported and are understood to the base of 1024. For <literal>tun</literal> or
 289             <literal>tap</literal> devices, <varname>MTUBytes=</varname> setting is not currently supported in
 290             <literal>[NetDev]</literal> section. Please specify it in <literal>[Link]</literal> section of
 291             corresponding
 292             <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 293             files.</para>
 294           </listitem>
 295         </varlistentry>
 296         <varlistentry>
 297           <term><varname>MACAddress=</varname></term>
 298           <listitem>
 299             <para>The MAC address to use for the device. For <literal>tun</literal> or <literal>tap</literal>
 300             devices, setting <varname>MACAddress=</varname> in the <literal>[NetDev]</literal> section is not
 301             supported. Please specify it in <literal>[Link]</literal> section of the corresponding
 302             <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 303             file. If this option is not set, <literal>vlan</literal> devices inherit the MAC address of the
 304             physical interface. For other kind of netdevs, if this option is not set, then MAC address is
 305             generated based on the interface name and the
 306             <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 307             </para>
 308           </listitem>
 309         </varlistentry>
 310       </variablelist>
 311   </refsect1>
 312
 313     <refsect1>
 314     <title>[Bridge] Section Options</title>
 315
 316       <para>The <literal>[Bridge]</literal> section only applies for
 317       netdevs of kind <literal>bridge</literal>, and accepts the
 318       following keys:</para>
 319
 320       <variablelist class='network-directives'>
 321         <varlistentry>
 322           <term><varname>HelloTimeSec=</varname></term>
 323           <listitem>
 324             <para>HelloTimeSec specifies the number of seconds between two hello packets
 325             sent out by the root bridge and the designated bridges. Hello packets are
 326             used to communicate information about the topology throughout the entire
 327             bridged local area network.</para>
 328           </listitem>
 329         </varlistentry>
 330         <varlistentry>
 331           <term><varname>MaxAgeSec=</varname></term>
 332           <listitem>
 333             <para>MaxAgeSec specifies the number of seconds of maximum message age.
 334             If the last seen (received) hello packet is more than this number of
 335             seconds old, the bridge in question will start the takeover procedure
 336             in attempt to become the Root Bridge itself.</para>
 337           </listitem>
 338         </varlistentry>
 339         <varlistentry>
 340           <term><varname>ForwardDelaySec=</varname></term>
 341           <listitem>
 342             <para>ForwardDelaySec specifies the number of seconds spent in each
 343             of the Listening and Learning states before the Forwarding state is entered.</para>
 344           </listitem>
 345         </varlistentry>
 346         <varlistentry>
 347           <term><varname>AgeingTimeSec=</varname></term>
 348           <listitem>
 349             <para>This specifies the number of seconds a MAC Address will be kept in
 350             the forwarding database after having a packet received from this MAC Address.</para>
 351           </listitem>
 352         </varlistentry>
 353         <varlistentry>
 354           <term><varname>Priority=</varname></term>
 355           <listitem>
 356             <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 357             means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 358           </listitem>
 359         </varlistentry>
 360         <varlistentry>
 361           <term><varname>GroupForwardMask=</varname></term>
 362           <listitem>
 363             <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 364             local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 365             is performed between the specified bitmask and the exponentiation of 2^X, the
 366             lower nibble of the last octet of the MAC address. For example, a value of 8
 367             would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 368           </listitem>
 369         </varlistentry>
 370         <varlistentry>
 371           <term><varname>DefaultPVID=</varname></term>
 372           <listitem>
 373             <para>This specifies the default port VLAN ID of a newly attached bridge port.
 374             Set this to an integer in the range 1–4094 or <literal>none</literal> to disable the PVID.</para>
 375           </listitem>
 376         </varlistentry>
 377         <varlistentry>
 378           <term><varname>MulticastQuerier=</varname></term>
 379           <listitem>
 380             <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 381             If enabled, the kernel will send general ICMP queries from a zero source address.
 382             This feature should allow faster convergence on startup, but it causes some
 383             multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 384             When unset, the kernel's default will be used.
 385             </para>
 386           </listitem>
 387         </varlistentry>
 388         <varlistentry>
 389           <term><varname>MulticastSnooping=</varname></term>
 390           <listitem>
 391             <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
 392             If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
 393             between hosts and multicast routers. When unset, the kernel's default will be used.
 394             </para>
 395           </listitem>
 396         </varlistentry>
 397         <varlistentry>
 398           <term><varname>VLANFiltering=</varname></term>
 399           <listitem>
 400             <para>Takes a boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 401             If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's default will be used.
 402             </para>
 403           </listitem>
 404         </varlistentry>
 405           <varlistentry>
 406           <term><varname>STP=</varname></term>
 407           <listitem>
 408             <para>Takes a boolean. This enables the bridge's Spanning Tree Protocol (STP).
 409             When unset, the kernel's default will be used.
 410             </para>
 411           </listitem>
 412         </varlistentry>
 413       </variablelist>
 414   </refsect1>
 415
 416   <refsect1>
 417     <title>[VLAN] Section Options</title>
 418
 419       <para>The <literal>[VLAN]</literal> section only applies for
 420       netdevs of kind <literal>vlan</literal>, and accepts the
 421       following key:</para>
 422
 423       <variablelist class='network-directives'>
 424         <varlistentry>
 425           <term><varname>Id=</varname></term>
 426           <listitem>
 427             <para>The VLAN ID to use. An integer in the range 0–4094.
 428             This option is compulsory.</para>
 429           </listitem>
 430         </varlistentry>
 431         <varlistentry>
 432           <term><varname>GVRP=</varname></term>
 433           <listitem>
 434             <para>Takes a boolean. The Generic VLAN Registration Protocol (GVRP) is a protocol that
 435             allows automatic learning of VLANs on a network.
 436             When unset, the kernel's default will be used.
 437             </para>
 438           </listitem>
 439         </varlistentry>
 440         <varlistentry>
 441           <term><varname>MVRP=</varname></term>
 442           <listitem>
 443             <para>Takes a boolean. Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 444             Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 445             for automatic configuration of VLAN information on switches. It was defined
 446             in the 802.1ak amendment to 802.1Q-2005. When unset, the kernel's default will be used.
 447             </para>
 448           </listitem>
 449         </varlistentry>
 450         <varlistentry>
 451           <term><varname>LooseBinding=</varname></term>
 452           <listitem>
 453             <para>Takes a boolean. The VLAN loose binding mode, in which only the operational state is passed
 454             from the parent to the associated VLANs, but the VLAN device state is not changed.
 455             When unset, the kernel's default will be used.</para>
 456           </listitem>
 457         </varlistentry>
 458         <varlistentry>
 459           <term><varname>ReorderHeader=</varname></term>
 460           <listitem>
 461             <para>Takes a boolean. The VLAN reorder header is set VLAN interfaces behave like physical interfaces.
 462             When unset, the kernel's default will be used.</para>
 463           </listitem>
 464         </varlistentry>
 465       </variablelist>
 466   </refsect1>
 467
 468   <refsect1>
 469     <title>[MACVLAN] Section Options</title>
 470
 471     <para>The <literal>[MACVLAN]</literal> section only applies for
 472     netdevs of kind <literal>macvlan</literal>, and accepts the
 473     following key:</para>
 474
 475     <variablelist class='network-directives'>
 476       <varlistentry>
 477         <term><varname>Mode=</varname></term>
 478         <listitem>
 479           <para>The MACVLAN mode to use. The supported options are
 480           <literal>private</literal>,
 481           <literal>vepa</literal>,
 482           <literal>bridge</literal>, and
 483           <literal>passthru</literal>.
 484           </para>
 485         </listitem>
 486       </varlistentry>
 487     </variablelist>
 488
 489   </refsect1>
 490
 491     <refsect1>
 492     <title>[MACVTAP] Section Options</title>
 493
 494     <para>The <literal>[MACVTAP]</literal> section applies for
 495     netdevs of kind <literal>macvtap</literal> and accepts the
 496     same key as <literal>[MACVLAN]</literal>.</para>
 497
 498     </refsect1>
 499
 500   <refsect1>
 501     <title>[IPVLAN] Section Options</title>
 502
 503     <para>The <literal>[IPVLAN]</literal> section only applies for
 504     netdevs of kind <literal>ipvlan</literal>, and accepts the
 505     following key:</para>
 506
 507     <variablelist class='network-directives'>
 508       <varlistentry>
 509         <term><varname>Mode=</varname></term>
 510           <listitem>
 511             <para>The IPVLAN mode to use. The supported options are
 512             <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 513             </para>
 514           </listitem>
 515       </varlistentry>
 516        <varlistentry>
 517         <term><varname>Flags=</varname></term>
 518           <listitem>
 519             <para>The IPVLAN flags to use. The supported options are
 520             <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 521             </para>
 522           </listitem>
 523       </varlistentry>
 524     </variablelist>
 525
 526   </refsect1>
 527
 528   <refsect1>
 529     <title>[IPVTAP] Section Options</title>
 530
 531     <para>The <literal>[IPVTAP]</literal> section only applies for
 532     netdevs of kind <literal>ipvtap</literal> and accepts the
 533     same key as <literal>[IPVLAN]</literal>.</para>
 534
 535   </refsect1>
 536
 537   <refsect1>
 538     <title>[VXLAN] Section Options</title>
 539     <para>The <literal>[VXLAN]</literal> section only applies for
 540     netdevs of kind <literal>vxlan</literal>, and accepts the
 541     following keys:</para>
 542
 543     <variablelist class='network-directives'>
 544       <varlistentry>
 545         <term><varname>VNI=</varname></term>
 546         <listitem>
 547           <para>The VXLAN Network Identifier (or VXLAN Segment ID). Takes a number in the range 1-16777215.</para>
 548         </listitem>
 549       </varlistentry>
 550       <varlistentry>
 551         <term><varname>Remote=</varname></term>
 552         <listitem>
 553           <para>Configures destination IP address.</para>
 554         </listitem>
 555       </varlistentry>
 556       <varlistentry>
 557         <term><varname>Local=</varname></term>
 558         <listitem>
 559           <para>Configures local IP address.</para>
 560         </listitem>
 561       </varlistentry>
 562       <varlistentry>
 563         <term><varname>Group=</varname></term>
 564         <listitem>
 565           <para>Configures VXLAN multicast group IP address. All members of a VXLAN must use the same multicast group address.</para>
 566         </listitem>
 567       </varlistentry>
 568         <varlistentry>
 569         <term><varname>TOS=</varname></term>
 570         <listitem>
 571           <para>The Type Of Service byte value for a vxlan interface.</para>
 572         </listitem>
 573       </varlistentry>
 574       <varlistentry>
 575         <term><varname>TTL=</varname></term>
 576         <listitem>
 577           <para>A fixed Time To Live N on Virtual eXtensible Local Area Network packets.
 578           Takes <literal>inherit</literal> or a number in the range 0–255. 0 is a special
 579           value meaning inherit the inner protocol's TTL value. <literal>inherit</literal>
 580           means that it will inherit the outer protocol's TTL value.</para>
 581         </listitem>
 582       </varlistentry>
 583       <varlistentry>
 584         <term><varname>MacLearning=</varname></term>
 585         <listitem>
 586           <para>Takes a boolean. When true, enables dynamic MAC learning
 587           to discover remote MAC addresses.</para>
 588         </listitem>
 589       </varlistentry>
 590       <varlistentry>
 591         <term><varname>FDBAgeingSec=</varname></term>
 592         <listitem>
 593           <para>The lifetime of Forwarding Database entry learnt by
 594           the kernel, in seconds.</para>
 595         </listitem>
 596       </varlistentry>
 597       <varlistentry>
 598         <term><varname>MaximumFDBEntries=</varname></term>
 599         <listitem>
 600           <para>Configures maximum number of FDB entries.</para>
 601         </listitem>
 602       </varlistentry>
 603       <varlistentry>
 604         <term><varname>ReduceARPProxy=</varname></term>
 605         <listitem>
 606           <para>Takes a boolean. When true, bridge-connected VXLAN tunnel
 607           endpoint answers ARP requests from the local bridge on behalf
 608           of remote Distributed Overlay Virtual Ethernet
 609           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 610           (DVOE)</ulink> clients. Defaults to false.</para>
 611         </listitem>
 612       </varlistentry>
 613       <varlistentry>
 614         <term><varname>L2MissNotification=</varname></term>
 615         <listitem>
 616           <para>Takes a boolean. When true, enables netlink LLADDR miss
 617           notifications.</para>
 618         </listitem>
 619       </varlistentry>
 620       <varlistentry>
 621         <term><varname>L3MissNotification=</varname></term>
 622         <listitem>
 623           <para>Takes a boolean. When true, enables netlink IP address miss
 624           notifications.</para>
 625         </listitem>
 626       </varlistentry>
 627       <varlistentry>
 628         <term><varname>RouteShortCircuit=</varname></term>
 629         <listitem>
 630           <para>Takes a boolean. When true, route short circuiting is turned
 631           on.</para>
 632         </listitem>
 633       </varlistentry>
 634       <varlistentry>
 635         <term><varname>UDPChecksum=</varname></term>
 636         <listitem>
 637           <para>Takes a boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 638         </listitem>
 639       </varlistentry>
 640       <varlistentry>
 641         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 642         <listitem>
 643           <para>Takes a boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 644         </listitem>
 645       </varlistentry>
 646       <varlistentry>
 647         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 648         <listitem>
 649           <para>Takes a boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 650         </listitem>
 651       </varlistentry>
 652       <varlistentry>
 653         <term><varname>RemoteChecksumTx=</varname></term>
 654         <listitem>
 655           <para>Takes a boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 656         </listitem>
 657       </varlistentry>
 658       <varlistentry>
 659         <term><varname>RemoteChecksumRx=</varname></term>
 660         <listitem>
 661           <para>Takes a boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 662         </listitem>
 663       </varlistentry>
 664     <varlistentry>
 665       <term><varname>GroupPolicyExtension=</varname></term>
 666       <listitem>
 667         <para>Takes a boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 668         across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 669         <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 670         VXLAN Group Policy </ulink> document. Defaults to false.</para>
 671       </listitem>
 672     </varlistentry>
 673     <varlistentry>
 674        <term><varname>GenericProtocolExtension=</varname></term>
 675        <listitem>
 676          <para>Takes a boolean. When true, Generic Protocol Extension extends the existing VXLAN protocol
 677          to provide protocol typing, OAM, and versioning capabilities. For details about the VXLAN GPE
 678          Header, see the <ulink url="https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-07">
 679          Generic Protocol Extension for VXLAN </ulink> document. If destination port is not specified and
 680          Generic Protocol Extension is set then default port of 4790 is used. Defaults to false.</para>
 681        </listitem>
 682     </varlistentry>
 683     <varlistentry>
 684       <term><varname>DestinationPort=</varname></term>
 685       <listitem>
 686         <para>Configures the default destination UDP port on a per-device basis.
 687         If destination port is not specified then Linux kernel default will be used.
 688         Set destination port 4789 to get the IANA assigned value. If not set or if the
 689         destination port is assigned the empty string the default port of 4789 is used.</para>
 690       </listitem>
 691     </varlistentry>
 692     <varlistentry>
 693       <term><varname>PortRange=</varname></term>
 694         <listitem>
 695           <para>Configures VXLAN port range. VXLAN bases source
 696           UDP port based on flow to help the receiver to be able
 697           to load balance based on outer header flow. It
 698           restricts the port range to the normal UDP local
 699           ports, and allows overriding via configuration.</para>
 700         </listitem>
 701       </varlistentry>
 702     <varlistentry>
 703       <term><varname>FlowLabel=</varname></term>
 704         <listitem>
 705           <para>Specifies the flow label to use in outgoing packets.
 706           The valid range is 0-1048575.
 707           </para>
 708         </listitem>
 709     </varlistentry>
 710       <varlistentry>
 711         <term><varname>IPDoNotFragment=</varname></term>
 712         <listitem>
 713           <para>Allows to set the IPv4 Do not Fragment (DF) bit in outgoing packets, or to inherit its
 714           value from the IPv4 inner header. Takes a boolean value, or <literal>inherit</literal>. Set
 715           to <literal>inherit</literal> if the encapsulated protocol is IPv6. When unset, the kernel's
 716           default will be used.</para>
 717         </listitem>
 718       </varlistentry>
 719     </variablelist>
 720   </refsect1>
 721   <refsect1>
 722     <title>[GENEVE] Section Options</title>
 723     <para>The <literal>[GENEVE]</literal> section only applies for
 724     netdevs of kind <literal>geneve</literal>, and accepts the
 725     following keys:</para>
 726
 727     <variablelist class='network-directives'>
 728       <varlistentry>
 729         <term><varname>Id=</varname></term>
 730         <listitem>
 731           <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [0-16777215]. This field is mandatory.</para>
 732         </listitem>
 733       </varlistentry>
 734       <varlistentry>
 735         <term><varname>Remote=</varname></term>
 736         <listitem>
 737           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 738         </listitem>
 739       </varlistentry>
 740       <varlistentry>
 741         <term><varname>TOS=</varname></term>
 742         <listitem>
 743           <para>Specifies the TOS value to use in outgoing packets. Ranges [1-255].</para>
 744         </listitem>
 745       </varlistentry>
 746       <varlistentry>
 747         <term><varname>TTL=</varname></term>
 748         <listitem>
 749           <para>Accepts the same key in <literal>[VXLAN]</literal> section except when unset or
 750           set to 0, the kernel's default will be used meaning that packets TTL will be set from
 751           <filename>/proc/sys/net/ipv4/ip_default_ttl</filename>.</para>
 752         </listitem>
 753       </varlistentry>
 754       <varlistentry>
 755         <term><varname>UDPChecksum=</varname></term>
 756         <listitem>
 757           <para>Takes a boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.</para>
 758         </listitem>
 759       </varlistentry>
 760       <varlistentry>
 761         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 762         <listitem>
 763           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 764         </listitem>
 765       </varlistentry>
 766       <varlistentry>
 767         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 768         <listitem>
 769           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 770         </listitem>
 771       </varlistentry>
 772     <varlistentry>
 773       <term><varname>DestinationPort=</varname></term>
 774       <listitem>
 775         <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 776         port of 6081 is used.</para>
 777       </listitem>
 778     </varlistentry>
 779     <varlistentry>
 780       <term><varname>FlowLabel=</varname></term>
 781         <listitem>
 782           <para>Specifies the flow label to use in outgoing packets.</para>
 783         </listitem>
 784     </varlistentry>
 785     <varlistentry>
 786       <term><varname>IPDoNotFragment=</varname></term>
 787         <listitem>
 788           <para>Accepts the same key in <literal>[VXLAN]</literal> section.</para>
 789         </listitem>
 790     </varlistentry>
 791     </variablelist>
 792   </refsect1>
 793   <refsect1>
 794     <title>[L2TP] Section Options</title>
 795     <para>The <literal>[L2TP]</literal> section only applies for
 796     netdevs of kind <literal>l2tp</literal>, and accepts the
 797     following keys:</para>
 798
 799     <variablelist class='network-directives'>
 800       <varlistentry>
 801         <term><varname>TunnelId=</varname></term>
 802         <listitem>
 803           <para>Specifies the tunnel id. The value used must match the <literal>PeerTunnelId=</literal> value being used at the peer.
 804           Ranges a number between 1 and 4294967295). This option is compulsory.</para>
 805         </listitem>
 806       </varlistentry>
 807       <varlistentry>
 808         <term><varname>PeerTunnelId=</varname></term>
 809         <listitem>
 810           <para>Specifies the peer tunnel id. The value used must match the <literal>PeerTunnelId=</literal> value being used at the peer.
 811           Ranges a number between 1 and 4294967295). This option is compulsory.</para>
 812         </listitem>
 813       </varlistentry>
 814       <varlistentry>
 815         <term><varname>Remote=</varname></term>
 816         <listitem>
 817           <para>Specifies the IP address of the remote peer. This option is compulsory.</para>
 818         </listitem>
 819       </varlistentry>
 820       <varlistentry>
 821         <term><varname>Local=</varname></term>
 822         <listitem>
 823           <para>Specifies the IP address of the local interface. Takes an IP address, or the special values
 824           <literal>auto</literal>, <literal>static</literal>, or <literal>dynamic</literal>. When an address
 825           is set, then the local interface must have the address. If <literal>auto</literal>, then one of the
 826           addresses on the local interface is used. Similarly, if <literal>static</literal> or
 827           <literal>dynamic</literal> is set, then one of the static or dynamic addresses on the local
 828           interface is used. Defaults to <literal>auto</literal>.</para>
 829         </listitem>
 830       </varlistentry>
 831       <varlistentry>
 832         <term><varname>EncapsulationType=</varname></term>
 833         <listitem>
 834           <para>Specifies the encapsulation type of the tunnel. Takes one of <literal>udp</literal> or <literal>ip</literal>.</para>
 835         </listitem>
 836       </varlistentry>
 837       <varlistentry>
 838         <term><varname>UDPSourcePort=</varname></term>
 839         <listitem>
 840           <para>Specifies the UDP source port to be used for the tunnel. When UDP encapsulation is selected it's mandotory. Ignored when ip
 841           encapsulation is selected.</para>
 842         </listitem>
 843       </varlistentry>
 844       <varlistentry>
 845         <term><varname>DestinationPort=</varname></term>
 846         <listitem>
 847           <para>Specifies destination port. When UDP encapsulation is selected it's mandotory. Ignored when ip
 848           encapsulation is selected.</para>
 849         </listitem>
 850       </varlistentry>
 851       <varlistentry>
 852         <term><varname>UDPChecksum=</varname></term>
 853         <listitem>
 854           <para>Takes a boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.</para>
 855         </listitem>
 856       </varlistentry>
 857       <varlistentry>
 858         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 859         <listitem>
 860           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 861         </listitem>
 862       </varlistentry>
 863       <varlistentry>
 864         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 865         <listitem>
 866           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 867         </listitem>
 868       </varlistentry>
 869     </variablelist>
 870   </refsect1>
 871   <refsect1>
 872     <title>[L2TPSession] Section Options</title>
 873     <para>The <literal>[L2TPSession]</literal> section only applies for
 874     netdevs of kind <literal>l2tp</literal>, and accepts the
 875     following keys:</para>
 876     <variablelist class='network-directives'>
 877       <varlistentry>
 878         <term><varname>Name=</varname></term>
 879         <listitem>
 880           <para>Specifies the name of the session. This option is compulsory.</para>
 881         </listitem>
 882       </varlistentry>
 883       <varlistentry>
 884         <term><varname>SessionId=</varname></term>
 885         <listitem>
 886           <para>Specifies the session id. The value used must match the <literal>SessionId=</literal> value being used at the peer.
 887           Ranges a number between 1 and 4294967295). This option is compulsory.</para>
 888         </listitem>
 889       </varlistentry>
 890       <varlistentry>
 891         <term><varname>PeerSessionId=</varname></term>
 892         <listitem>
 893           <para>Specifies the peer session id. The value used must match the <literal>PeerSessionId=</literal> value being used at the peer.
 894           Ranges a number between 1 and 4294967295). This option is compulsory.</para>
 895         </listitem>
 896       </varlistentry>
 897       <varlistentry>
 898         <term><varname>Layer2SpecificHeader=</varname></term>
 899         <listitem>
 900           <para>Specifies layer2specific header type of the session. One of <literal>none</literal> or <literal>default</literal>. Defaults to <literal>default</literal>.</para>
 901         </listitem>
 902       </varlistentry>
 903     </variablelist>
 904   </refsect1>
 905   <refsect1>
 906     <title>[MACsec] Section Options</title>
 907     <para>The <literal>[MACsec]</literal> section only applies for network devices of kind
 908     <literal>macsec</literal>, and accepts the following keys:</para>
 909
 910     <variablelist class='network-directives'>
 911       <varlistentry>
 912         <term><varname>Port=</varname></term>
 913         <listitem>
 914           <para>Specifies the port to be used for the MACsec transmit channel. The port is used to make
 915           secure channel identifier (SCI). Takes a value between 1 and 65535. Defaults to unset.
 916           </para>
 917         </listitem>
 918       </varlistentry>
 919       <varlistentry>
 920         <term><varname>Encrypt=</varname></term>
 921         <listitem>
 922           <para>Takes a boolean. When true, enable encryption. Defaults to unset.</para>
 923         </listitem>
 924       </varlistentry>
 925     </variablelist>
 926   </refsect1>
 927   <refsect1>
 928     <title>[MACsecReceiveChannel] Section Options</title>
 929     <para>The <literal>[MACsecReceiveChannel]</literal> section only applies for network devices of
 930     kind <literal>macsec</literal>, and accepts the following keys:</para>
 931
 932     <variablelist class='network-directives'>
 933       <varlistentry>
 934         <term><varname>Port=</varname></term>
 935         <listitem>
 936           <para>Specifies the port to be used for the MACsec receive channel. The port is used to make
 937           secure channel identifier (SCI). Takes a value between 1 and 65535. This option is
 938           compulsory, and is not set by default.</para>
 939         </listitem>
 940       </varlistentry>
 941       <varlistentry>
 942         <term><varname>MACAddress=</varname></term>
 943         <listitem>
 944           <para>Specifies the MAC address to be used for the MACsec receive channel. The MAC address
 945           used to make secure channel identifier (SCI). This option is compulsory, and is not set by
 946           default.</para>
 947         </listitem>
 948       </varlistentry>
 949     </variablelist>
 950   </refsect1>
 951   <refsect1>
 952     <title>[MACsecTransmitAssociation] Section Options</title>
 953     <para>The <literal>[MACsecTransmitAssociation]</literal> section only applies for network devices
 954     of kind <literal>macsec</literal>, and accepts the following keys:</para>
 955
 956     <variablelist class='network-directives'>
 957       <varlistentry>
 958         <term><varname>PacketNumber=</varname></term>
 959         <listitem>
 960           <para>Specifies the packet number to be used for replay protection and the construction of
 961           the initialization vector (along with the secure channel identifier [SCI]). Takes a value
 962           between 1-4,294,967,295. Defaults to unset.
 963           </para>
 964         </listitem>
 965       </varlistentry>
 966       <varlistentry>
 967         <term><varname>KeyId=</varname></term>
 968         <listitem>
 969           <para>Specifies the identification for the key. Takes a number between 0-255. This option
 970           is compulsory, and is not set by default.</para>
 971         </listitem>
 972       </varlistentry>
 973       <varlistentry>
 974         <term><varname>Key=</varname></term>
 975         <listitem>
 976           <para>Specifies the encryption key used in the transmission channel. The same key must be
 977           configured on the peer’s matching receive channel. This option is compulsory, and is not set
 978           by default. Takes a 128-bit key encoded in a hexadecimal string, for example
 979           <literal>dffafc8d7b9a43d5b9a3dfbbf6a30c16</literal>.</para>
 980         </listitem>
 981       </varlistentry>
 982       <varlistentry>
 983         <term><varname>KeyFile=</varname></term>
 984         <listitem>
 985           <para>Takes a absolute path to a file which contains a 128-bit key encoded in a hexadecimal
 986           string, which will be used in the transmission channel. When this option is specified,
 987           <varname>Key=</varname> is ignored. Note that the file must be readable by the user
 988           <literal>systemd-network</literal>, so it should be, e.g., owned by
 989           <literal>root:systemd-network</literal> with a <literal>0640</literal> file mode.</para>
 990         </listitem>
 991       </varlistentry>
 992       <varlistentry>
 993         <term><varname>Activate=</varname></term>
 994         <listitem>
 995           <para>Takes a boolean. If enabled, then the security association is activated. Defaults to
 996           unset.</para>
 997         </listitem>
 998       </varlistentry>
 999       <varlistentry>
1000         <term><varname>UseForEncoding=</varname></term>
1001         <listitem>
1002           <para>Takes a boolean. If enabled, then the security association is used for encoding. Only
1003           one <literal>[MACsecTransmitAssociation]</literal> section can enable this option. When enabled,
1004           <varname>Activate=yes</varname> is implied. Defaults to unset.</para>
1005         </listitem>
1006       </varlistentry>
1007     </variablelist>
1008   </refsect1>
1009   <refsect1>
1010     <title>[MACsecReceiveAssociation] Section Options</title>
1011     <para>The <literal>[MACsecReceiveAssociation]</literal> section only applies for
1012     network devices of kind <literal>macsec</literal>, and accepts the
1013     following keys:</para>
1014
1015     <variablelist class='network-directives'>
1016       <varlistentry>
1017         <term><varname>Port=</varname></term>
1018         <listitem>
1019           <para>Accepts the same key in <literal>[MACsecReceiveChannel]</literal> section.</para>
1020         </listitem>
1021       </varlistentry>
1022       <varlistentry>
1023         <term><varname>MACAddress=</varname></term>
1024         <listitem>
1025           <para>Accepts the same key in <literal>[MACsecReceiveChannel]</literal> section.</para>
1026         </listitem>
1027       </varlistentry>
1028       <varlistentry>
1029         <term><varname>PacketNumber=</varname></term>
1030         <listitem>
1031           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1032         </listitem>
1033       </varlistentry>
1034       <varlistentry>
1035         <term><varname>KeyId=</varname></term>
1036         <listitem>
1037           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1038         </listitem>
1039       </varlistentry>
1040       <varlistentry>
1041         <term><varname>Key=</varname></term>
1042         <listitem>
1043           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1044         </listitem>
1045       </varlistentry>
1046       <varlistentry>
1047         <term><varname>KeyFile=</varname></term>
1048         <listitem>
1049           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1050         </listitem>
1051       </varlistentry>
1052       <varlistentry>
1053         <term><varname>Activate=</varname></term>
1054         <listitem>
1055           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1056         </listitem>
1057       </varlistentry>
1058     </variablelist>
1059   </refsect1>
1060   <refsect1>
1061     <title>[Tunnel] Section Options</title>
1062
1063     <para>The <literal>[Tunnel]</literal> section only applies for
1064     netdevs of kind
1065     <literal>ipip</literal>,
1066     <literal>sit</literal>,
1067     <literal>gre</literal>,
1068     <literal>gretap</literal>,
1069     <literal>ip6gre</literal>,
1070     <literal>ip6gretap</literal>,
1071     <literal>vti</literal>,
1072     <literal>vti6</literal>,
1073     <literal>ip6tnl</literal>, and
1074     <literal>erspan</literal> and accepts
1075     the following keys:</para>
1076
1077     <variablelist class='network-directives'>
1078       <varlistentry>
1079         <term><varname>Local=</varname></term>
1080         <listitem>
1081           <para>A static local address for tunneled packets. It must be an address on another interface of
1082           this host, or the special value <literal>any</literal>.</para>
1083         </listitem>
1084       </varlistentry>
1085       <varlistentry>
1086         <term><varname>Remote=</varname></term>
1087         <listitem>
1088           <para>The remote endpoint of the tunnel. Takes an IP address or the special value
1089           <literal>any</literal>.</para>
1090         </listitem>
1091       </varlistentry>
1092       <varlistentry>
1093         <term><varname>TOS=</varname></term>
1094         <listitem>
1095           <para>The Type Of Service byte value for a tunnel interface.
1096           For details about the TOS, see the
1097           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
1098           Service in the Internet Protocol Suite </ulink> document.
1099           </para>
1100         </listitem>
1101       </varlistentry>
1102       <varlistentry>
1103         <term><varname>TTL=</varname></term>
1104         <listitem>
1105           <para>A fixed Time To Live N on tunneled packets. N is a
1106           number in the range 1–255. 0 is a special value meaning that
1107           packets inherit the TTL value. The default value for IPv4
1108           tunnels is: inherit. The default value for IPv6 tunnels is
1109           64.</para>
1110         </listitem>
1111       </varlistentry>
1112       <varlistentry>
1113         <term><varname>DiscoverPathMTU=</varname></term>
1114         <listitem>
1115           <para>Takes a boolean. When true, enables Path MTU Discovery on
1116           the tunnel.</para>
1117         </listitem>
1118       </varlistentry>
1119       <varlistentry>
1120         <term><varname>IPv6FlowLabel=</varname></term>
1121         <listitem>
1122           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
1123           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
1124           RFC 2460</ulink>), which is used by a node to label packets of a flow.
1125           It is only used for IPv6 tunnels.
1126           A flow label of zero is used to indicate packets that have
1127           not been labeled.
1128           It can be configured to a value in the range 0–0xFFFFF, or be
1129           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
1130         </listitem>
1131       </varlistentry>
1132       <varlistentry>
1133         <term><varname>CopyDSCP=</varname></term>
1134         <listitem>
1135           <para>Takes a boolean. When true, the Differentiated Service Code
1136           Point (DSCP) field will be copied to the inner header from
1137           outer header during the decapsulation of an IPv6 tunnel
1138           packet. DSCP is a field in an IP packet that enables different
1139           levels of service to be assigned to network traffic.
1140           Defaults to <literal>no</literal>.
1141           </para>
1142         </listitem>
1143       </varlistentry>
1144       <varlistentry>
1145         <term><varname>EncapsulationLimit=</varname></term>
1146         <listitem>
1147           <para>The Tunnel Encapsulation Limit option specifies how many additional
1148           levels of encapsulation are permitted to be prepended to the packet.
1149           For example, a Tunnel Encapsulation Limit option containing a limit
1150           value of zero means that a packet carrying that option may not enter
1151           another tunnel before exiting the current tunnel.
1152           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
1153           The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
1154         </para>
1155         </listitem>
1156       </varlistentry>
1157       <varlistentry>
1158         <term><varname>Key=</varname></term>
1159         <listitem>
1160           <para>The <varname>Key=</varname> parameter specifies the same key to use in
1161           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
1162           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
1163           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
1164           and control path) in ip xfrm (framework used to implement IPsec protocol).
1165           See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
1166           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6,
1167           GRE, GRETAP, and ERSPAN tunnels.</para>
1168         </listitem>
1169       </varlistentry>
1170       <varlistentry>
1171         <term><varname>InputKey=</varname></term>
1172         <listitem>
1173           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
1174           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1175           and ERSPAN tunnels.</para>
1176         </listitem>
1177       </varlistentry>
1178       <varlistentry>
1179         <term><varname>OutputKey=</varname></term>
1180         <listitem>
1181           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
1182           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1183           and ERSPAN tunnels.</para>
1184         </listitem>
1185       </varlistentry>
1186       <varlistentry>
1187         <term><varname>Mode=</varname></term>
1188         <listitem>
1189           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
1190           modes
1191           <literal>ip6ip6</literal> for IPv6 over IPv6,
1192           <literal>ipip6</literal> for IPv4 over IPv6 or
1193           <literal>any</literal> for either.
1194           </para>
1195         </listitem>
1196       </varlistentry>
1197       <varlistentry>
1198         <term><varname>Independent=</varname></term>
1199         <listitem>
1200           <para>Takes a boolean. When true tunnel does not require .network file. Created as "tunnel@NONE".
1201           Defaults to <literal>false</literal>.
1202           </para>
1203         </listitem>
1204       </varlistentry>
1205       <varlistentry>
1206         <term><varname>AllowLocalRemote=</varname></term>
1207         <listitem>
1208           <para>Takes a boolean. When true allows tunnel traffic on <varname>ip6tnl</varname> devices where the remote endpoint is a local host address.
1209           When unset, the kernel's default will be used.
1210           </para>
1211         </listitem>
1212       </varlistentry>
1213       <varlistentry>
1214         <term><varname>FooOverUDP=</varname></term>
1215         <listitem>
1216           <para>Takes a boolean. Specifies whether <varname>FooOverUDP=</varname> tunnel is to be configured.
1217           Defaults to false. This takes effects only for IPIP, SIT, GRE, and GRETAP tunnels.
1218           For more detail information see
1219           <ulink url="https://lwn.net/Articles/614348">Foo over UDP</ulink></para>
1220         </listitem>
1221       </varlistentry>
1222       <varlistentry>
1223         <term><varname>FOUDestinationPort=</varname></term>
1224         <listitem>
1225           <para>This setting specifies the UDP destination port for encapsulation.
1226           This field is mandatory when <varname>FooOverUDP=yes</varname>, and is not set by default.</para>
1227         </listitem>
1228       </varlistentry>
1229       <varlistentry>
1230         <term><varname>FOUSourcePort=</varname></term>
1231         <listitem>
1232           <para>This setting specifies the UDP source port for encapsulation. Defaults to <constant>0</constant>
1233           — that is, the source port for packets is left to the network stack to decide.</para>
1234         </listitem>
1235       </varlistentry>
1236       <varlistentry>
1237         <term><varname>Encapsulation=</varname></term>
1238         <listitem>
1239           <para>Accepts the same key as in the <literal>[FooOverUDP]</literal> section.</para>
1240         </listitem>
1241       </varlistentry>
1242       <varlistentry>
1243         <term><varname>IPv6RapidDeploymentPrefix=</varname></term>
1244         <listitem>
1245           <para>Reconfigure the tunnel for <ulink url="https://tools.ietf.org/html/rfc5569">IPv6 Rapid
1246           Deployment</ulink>, also known as 6rd. The value is an ISP-specific IPv6 prefix with a non-zero length. Only
1247           applicable to SIT tunnels.</para>
1248         </listitem>
1249       </varlistentry>
1250       <varlistentry>
1251         <term><varname>ISATAP=</varname></term>
1252         <listitem>
1253           <para>Takes a boolean. If set, configures the tunnel as Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) tunnel.
1254           Only applicable to SIT tunnels. When unset, the kernel's default will be used.</para>
1255         </listitem>
1256       </varlistentry>
1257       <varlistentry>
1258         <term><varname>SerializeTunneledPackets=</varname></term>
1259         <listitem>
1260           <para>Takes a boolean. If set to yes, then packets are serialized. Only applies for GRE,
1261           GRETAP, and ERSPAN tunnels. When unset, the kernel's default will be used.
1262           </para>
1263         </listitem>
1264       </varlistentry>
1265       <varlistentry>
1266         <term><varname>ERSPANIndex=</varname></term>
1267         <listitem>
1268           <para>Specifies the ERSPAN index field for the interface, an integer in the range 1-1048575 associated with
1269           the ERSPAN traffic's source port and direction. This field is mandatory.
1270           </para>
1271         </listitem>
1272       </varlistentry>
1273     </variablelist>
1274   </refsect1>
1275
1276   <refsect1>
1277     <title>[FooOverUDP] Section Options</title>
1278
1279     <para>The <literal>[FooOverUDP]</literal> section only applies for
1280     netdevs of kind <literal>fou</literal> and accepts the
1281     following keys:</para>
1282
1283     <variablelist class='network-directives'>
1284       <varlistentry>
1285         <term><varname>Encapsulation=</varname></term>
1286         <listitem>
1287           <para>Specifies the encapsulation mechanism used to store networking packets of various protocols inside the UDP packets. Supports the following values:
1288
1289           <literal>FooOverUDP</literal> provides the simplest no frills model of UDP encapsulation, it simply encapsulates
1290           packets directly in the UDP payload.
1291           <literal>GenericUDPEncapsulation</literal> is a generic and extensible encapsulation, it allows encapsulation of packets for any IP
1292           protocol and optional data as part of the encapsulation.
1293           For more detailed information see <ulink url="https://lwn.net/Articles/615044">Generic UDP Encapsulation</ulink>.
1294           Defaults to <literal>FooOverUDP</literal>.
1295           </para>
1296         </listitem>
1297       </varlistentry>
1298       <varlistentry>
1299         <term><varname>Port=</varname></term>
1300         <listitem>
1301           <para>Specifies the port number, where the IP encapsulation packets will arrive. Please take note that the packets
1302           will arrive with the encapsulation will be removed. Then they will be manually fed back into the network stack, and sent ahead
1303           for delivery to the real destination. This option is mandatory.</para>
1304         </listitem>
1305         </varlistentry>
1306       <varlistentry>
1307         <term><varname>PeerPort=</varname></term>
1308         <listitem>
1309           <para>Specifies the peer port number. Defaults to unset. Note that when peer port is set <literal>Peer=</literal> address is mandotory.</para>
1310         </listitem>
1311         </varlistentry>
1312       <varlistentry>
1313         <term><varname>Protocol=</varname></term>
1314         <listitem>
1315           <para>The <varname>Protocol=</varname> specifies the protocol number of the packets arriving
1316           at the UDP port. When <varname>Encapsulation=FooOverUDP</varname>, this field is mandatory
1317           and is not set by default. Takes an IP protocol name such as <literal>gre</literal> or
1318           <literal>ipip</literal>, or an integer within the range 1-255. When
1319           <varname>Encapsulation=GenericUDPEncapsulation</varname>, this must not be specified.</para>
1320         </listitem>
1321       </varlistentry>
1322       <varlistentry>
1323         <term><varname>Peer=</varname></term>
1324         <listitem>
1325           <para>Configures peer IP address. Note that when peer address is set <literal>PeerPort=</literal> is mandotory.</para>
1326         </listitem>
1327       </varlistentry>
1328       <varlistentry>
1329         <term><varname>Local=</varname></term>
1330         <listitem>
1331           <para>Configures local IP address.</para>
1332         </listitem>
1333       </varlistentry>
1334     </variablelist>
1335   </refsect1>
1336   <refsect1>
1337     <title>[Peer] Section Options</title>
1338
1339       <para>The <literal>[Peer]</literal> section only applies for
1340       netdevs of kind <literal>veth</literal> and accepts the
1341       following keys:</para>
1342
1343       <variablelist class='network-directives'>
1344         <varlistentry>
1345           <term><varname>Name=</varname></term>
1346           <listitem>
1347             <para>The interface name used when creating the netdev.
1348             This option is compulsory.</para>
1349           </listitem>
1350         </varlistentry>
1351         <varlistentry>
1352           <term><varname>MACAddress=</varname></term>
1353           <listitem>
1354             <para>The peer MACAddress, if not set, it is generated in
1355             the same way as the MAC address of the main
1356             interface.</para>
1357           </listitem>
1358         </varlistentry>
1359       </variablelist>
1360   </refsect1>
1361   <refsect1>
1362   <title>[VXCAN] Section Options</title>
1363       <para>The <literal>[VXCAN]</literal> section only applies for
1364       netdevs of kind <literal>vxcan</literal> and accepts the
1365       following key:</para>
1366
1367       <variablelist class='network-directives'>
1368         <varlistentry>
1369           <term><varname>Peer=</varname></term>
1370           <listitem>
1371             <para>The peer interface name used when creating the netdev.
1372             This option is compulsory.</para>
1373           </listitem>
1374         </varlistentry>
1375       </variablelist>
1376   </refsect1>
1377   <refsect1>
1378     <title>[Tun] Section Options</title>
1379
1380     <para>The <literal>[Tun]</literal> section only applies for
1381     netdevs of kind <literal>tun</literal>, and accepts the following
1382     keys:</para>
1383
1384     <variablelist class='network-directives'>
1385       <varlistentry>
1386         <term><varname>MultiQueue=</varname></term>
1387         <listitem><para>Takes a boolean. Configures whether
1388         to use multiple file descriptors (queues) to parallelize
1389         packets sending and receiving. Defaults to
1390         <literal>no</literal>.</para>
1391         </listitem>
1392       </varlistentry>
1393       <varlistentry>
1394         <term><varname>PacketInfo=</varname></term>
1395         <listitem><para>Takes a boolean. Configures whether
1396         packets should be prepended with four extra bytes (two flag
1397         bytes and two protocol bytes). If disabled, it indicates that
1398         the packets will be pure IP packets. Defaults to
1399         <literal>no</literal>.</para>
1400         </listitem>
1401       </varlistentry>
1402       <varlistentry>
1403         <term><varname>VNetHeader=</varname></term>
1404         <listitem><para>Takes a boolean. Configures
1405         IFF_VNET_HDR flag for a tun or tap device. It allows sending
1406         and receiving larger Generic Segmentation Offload (GSO)
1407         packets. This may increase throughput significantly.
1408         Defaults to
1409         <literal>no</literal>.</para>
1410         </listitem>
1411       </varlistentry>
1412       <varlistentry>
1413         <term><varname>User=</varname></term>
1414         <listitem><para>User to grant access to the
1415         <filename>/dev/net/tun</filename> device.</para>
1416         </listitem>
1417       </varlistentry>
1418       <varlistentry>
1419         <term><varname>Group=</varname></term>
1420         <listitem><para>Group to grant access to the
1421         <filename>/dev/net/tun</filename> device.</para>
1422         </listitem>
1423       </varlistentry>
1424
1425     </variablelist>
1426
1427   </refsect1>
1428
1429   <refsect1>
1430     <title>[Tap] Section Options</title>
1431
1432     <para>The <literal>[Tap]</literal> section only applies for
1433     netdevs of kind <literal>tap</literal>, and accepts the same keys
1434     as the <literal>[Tun]</literal> section.</para>
1435   </refsect1>
1436
1437   <refsect1>
1438     <title>[WireGuard] Section Options</title>
1439
1440     <para>The <literal>[WireGuard]</literal> section accepts the following
1441     keys:</para>
1442
1443     <variablelist class='network-directives'>
1444       <varlistentry>
1445         <term><varname>PrivateKey=</varname></term>
1446         <listitem>
1447           <para>The Base64 encoded private key for the interface. It can be
1448             generated using the <command>wg genkey</command> command
1449             (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1450             This option or <varname>PrivateKeyFile=</varname> is mandatory to use WireGuard.
1451             Note that because this information is secret, you may want to set
1452             the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1453             with a <literal>0640</literal> file mode.</para>
1454         </listitem>
1455       </varlistentry>
1456       <varlistentry>
1457         <term><varname>PrivateKeyFile=</varname></term>
1458         <listitem>
1459           <para>Takes an absolute path to a file which contains the Base64 encoded private key for the interface.
1460           When this option is specified, then <varname>PrivateKey=</varname> is ignored.
1461           Note that the file must be readable by the user <literal>systemd-network</literal>, so it
1462           should be, e.g., owned by <literal>root:systemd-network</literal> with a
1463           <literal>0640</literal> file mode.</para>
1464         </listitem>
1465       </varlistentry>
1466       <varlistentry>
1467         <term><varname>ListenPort=</varname></term>
1468         <listitem>
1469           <para>Sets UDP port for listening. Takes either value between 1 and 65535
1470             or <literal>auto</literal>. If <literal>auto</literal> is specified,
1471             the port is automatically generated based on interface name.
1472             Defaults to <literal>auto</literal>.</para>
1473         </listitem>
1474       </varlistentry>
1475       <varlistentry>
1476         <term><varname>FirewallMark=</varname></term>
1477         <listitem>
1478           <para>Sets a firewall mark on outgoing WireGuard packets from this interface. Takes a number between 1 and 4294967295.</para>
1479         </listitem>
1480       </varlistentry>
1481     </variablelist>
1482   </refsect1>
1483
1484   <refsect1>
1485     <title>[WireGuardPeer] Section Options</title>
1486
1487     <para>The <literal>[WireGuardPeer]</literal> section accepts the following
1488     keys:</para>
1489
1490     <variablelist class='network-directives'>
1491       <varlistentry>
1492         <term><varname>PublicKey=</varname></term>
1493         <listitem>
1494           <para>Sets a Base64 encoded public key calculated by <command>wg pubkey</command>
1495             (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1496             from a private key, and usually transmitted out of band to the
1497             author of the configuration file. This option is mandatory for this
1498             section.</para>
1499         </listitem>
1500       </varlistentry>
1501       <varlistentry>
1502         <term><varname>PresharedKey=</varname></term>
1503         <listitem>
1504           <para>Optional preshared key for the interface. It can be generated
1505             by the <command>wg genpsk</command> command. This option adds an
1506             additional layer of symmetric-key cryptography to be mixed into the
1507             already existing public-key cryptography, for post-quantum
1508             resistance.
1509             Note that because this information is secret, you may want to set
1510             the permissions of the .netdev file to be owned by <literal>root:systemd-networkd</literal>
1511             with a <literal>0640</literal> file mode.</para>
1512         </listitem>
1513       </varlistentry>
1514       <varlistentry>
1515         <term><varname>PresharedKeyFile=</varname></term>
1516         <listitem>
1517           <para>Takes an absolute path to a file which contains the Base64 encoded preshared key for the
1518           peer. When this option is specified, then <varname>PresharedKey=</varname> is ignored.
1519           Note that the file must be readable by the user <literal>systemd-network</literal>, so it
1520           should be, e.g., owned by <literal>root:systemd-network</literal> with a
1521           <literal>0640</literal> file mode.</para>
1522         </listitem>
1523       </varlistentry>
1524       <varlistentry>
1525         <term><varname>AllowedIPs=</varname></term>
1526         <listitem>
1527           <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks
1528             from which this peer is allowed to send incoming traffic and to
1529             which outgoing traffic for this peer is directed. The catch-all
1530             0.0.0.0/0 may be specified for matching all IPv4 addresses, and
1531             ::/0 may be specified for matching all IPv6 addresses. </para>
1532         </listitem>
1533       </varlistentry>
1534       <varlistentry>
1535         <term><varname>Endpoint=</varname></term>
1536         <listitem>
1537           <para>Sets an endpoint IP address or hostname, followed by a colon, and then
1538             a port number. This endpoint will be updated automatically once to
1539             the most recent source IP address and port of correctly
1540             authenticated packets from the peer at configuration time.</para>
1541         </listitem>
1542       </varlistentry>
1543       <varlistentry>
1544         <term><varname>PersistentKeepalive=</varname></term>
1545         <listitem>
1546           <para>Sets a seconds interval, between 1 and 65535 inclusive, of how often
1547             to send an authenticated empty packet to the peer for the purpose
1548             of keeping a stateful firewall or NAT mapping valid persistently.
1549             For example, if the interface very rarely sends traffic, but it
1550             might at anytime receive traffic from a peer, and it is behind NAT,
1551             the interface might benefit from having a persistent keepalive
1552             interval of 25 seconds. If set to 0 or "off", this option is
1553             disabled. By default or when unspecified, this option is off.
1554             Most users will not need this.</para>
1555         </listitem>
1556       </varlistentry>
1557     </variablelist>
1558   </refsect1>
1559
1560   <refsect1>
1561     <title>[Bond] Section Options</title>
1562
1563     <para>The <literal>[Bond]</literal> section accepts the following
1564     key:</para>
1565
1566     <variablelist class='network-directives'>
1567       <varlistentry>
1568         <term><varname>Mode=</varname></term>
1569         <listitem>
1570           <para>Specifies one of the bonding policies. The default is
1571           <literal>balance-rr</literal> (round robin). Possible values are
1572           <literal>balance-rr</literal>,
1573           <literal>active-backup</literal>,
1574           <literal>balance-xor</literal>,
1575           <literal>broadcast</literal>,
1576           <literal>802.3ad</literal>,
1577           <literal>balance-tlb</literal>, and
1578           <literal>balance-alb</literal>.
1579           </para>
1580         </listitem>
1581       </varlistentry>
1582
1583       <varlistentry>
1584         <term><varname>TransmitHashPolicy=</varname></term>
1585         <listitem>
1586           <para>Selects the transmit hash policy to use for slave
1587           selection in balance-xor, 802.3ad, and tlb modes. Possible
1588           values are
1589           <literal>layer2</literal>,
1590           <literal>layer3+4</literal>,
1591           <literal>layer2+3</literal>,
1592           <literal>encap2+3</literal>, and
1593           <literal>encap3+4</literal>.
1594           </para>
1595         </listitem>
1596       </varlistentry>
1597
1598       <varlistentry>
1599         <term><varname>LACPTransmitRate=</varname></term>
1600         <listitem>
1601           <para>Specifies the rate with which link partner transmits
1602           Link Aggregation Control Protocol Data Unit packets in
1603           802.3ad mode. Possible values are <literal>slow</literal>,
1604           which requests partner to transmit LACPDUs every 30 seconds,
1605           and <literal>fast</literal>, which requests partner to
1606           transmit LACPDUs every second. The default value is
1607           <literal>slow</literal>.</para>
1608         </listitem>
1609       </varlistentry>
1610
1611       <varlistentry>
1612         <term><varname>MIIMonitorSec=</varname></term>
1613         <listitem>
1614           <para>Specifies the frequency that Media Independent
1615           Interface link monitoring will occur. A value of zero
1616           disables MII link monitoring. This value is rounded down to
1617           the nearest millisecond. The default value is 0.</para>
1618         </listitem>
1619       </varlistentry>
1620
1621       <varlistentry>
1622         <term><varname>UpDelaySec=</varname></term>
1623         <listitem>
1624           <para>Specifies the delay before a link is enabled after a
1625           link up status has been detected. This value is rounded down
1626           to a multiple of MIIMonitorSec. The default value is
1627           0.</para>
1628         </listitem>
1629       </varlistentry>
1630
1631       <varlistentry>
1632         <term><varname>DownDelaySec=</varname></term>
1633         <listitem>
1634           <para>Specifies the delay before a link is disabled after a
1635           link down status has been detected. This value is rounded
1636           down to a multiple of MIIMonitorSec. The default value is
1637           0.</para>
1638         </listitem>
1639       </varlistentry>
1640
1641       <varlistentry>
1642         <term><varname>LearnPacketIntervalSec=</varname></term>
1643         <listitem>
1644           <para>Specifies the number of seconds between instances where the bonding
1645           driver sends learning packets to each slave peer switch.
1646           The valid range is 1–0x7fffffff; the default value is 1. This option
1647           has an effect only for the balance-tlb and balance-alb modes.</para>
1648         </listitem>
1649       </varlistentry>
1650
1651       <varlistentry>
1652         <term><varname>AdSelect=</varname></term>
1653         <listitem>
1654           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
1655           <literal>stable</literal>,
1656           <literal>bandwidth</literal> and
1657           <literal>count</literal>.
1658           </para>
1659         </listitem>
1660       </varlistentry>
1661
1662       <varlistentry>
1663         <term><varname>AdActorSystemPriority=</varname></term>
1664         <listitem>
1665           <para>Specifies the 802.3ad actor system priority. Ranges [1-65535].</para>
1666         </listitem>
1667       </varlistentry>
1668
1669       <varlistentry>
1670         <term><varname>AdUserPortKey=</varname></term>
1671         <listitem>
1672           <para>Specifies the 802.3ad user defined portion of the port key. Ranges [0-1023].</para>
1673         </listitem>
1674       </varlistentry>
1675
1676       <varlistentry>
1677         <term><varname>AdActorSystem=</varname></term>
1678         <listitem>
1679           <para>Specifies the 802.3ad system mac address. This can not be either NULL or Multicast.</para>
1680         </listitem>
1681       </varlistentry>
1682
1683       <varlistentry>
1684         <term><varname>FailOverMACPolicy=</varname></term>
1685         <listitem>
1686           <para>Specifies whether the active-backup mode should set all slaves to
1687           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1688           bond's MAC address in accordance with the selected policy. The default policy is none.
1689           Possible values are
1690           <literal>none</literal>,
1691           <literal>active</literal> and
1692           <literal>follow</literal>.
1693           </para>
1694         </listitem>
1695       </varlistentry>
1696
1697       <varlistentry>
1698         <term><varname>ARPValidate=</varname></term>
1699         <listitem>
1700           <para>Specifies whether or not ARP probes and replies should be
1701           validated in any mode that supports ARP monitoring, or whether
1702           non-ARP traffic should be filtered (disregarded) for link
1703           monitoring purposes. Possible values are
1704           <literal>none</literal>,
1705           <literal>active</literal>,
1706           <literal>backup</literal> and
1707           <literal>all</literal>.
1708           </para>
1709         </listitem>
1710       </varlistentry>
1711
1712       <varlistentry>
1713         <term><varname>ARPIntervalSec=</varname></term>
1714         <listitem>
1715           <para>Specifies the ARP link monitoring frequency in milliseconds.
1716           A value of 0 disables ARP monitoring. The default value is 0.
1717           </para>
1718         </listitem>
1719       </varlistentry>
1720
1721       <varlistentry>
1722         <term><varname>ARPIPTargets=</varname></term>
1723         <listitem>
1724           <para>Specifies the IP addresses to use as ARP monitoring peers when
1725           ARPIntervalSec is greater than 0. These are the targets of the ARP request
1726           sent to determine the health of the link to the targets.
1727           Specify these values in IPv4 dotted decimal format. At least one IP
1728           address must be given for ARP monitoring to function. The
1729           maximum number of targets that can be specified is 16. The
1730           default value is no IP addresses.
1731           </para>
1732         </listitem>
1733       </varlistentry>
1734
1735       <varlistentry>
1736         <term><varname>ARPAllTargets=</varname></term>
1737         <listitem>
1738           <para>Specifies the quantity of ARPIPTargets that must be reachable
1739           in order for the ARP monitor to consider a slave as being up.
1740           This option affects only active-backup mode for slaves with
1741           ARPValidate enabled. Possible values are
1742           <literal>any</literal> and
1743           <literal>all</literal>.
1744           </para>
1745         </listitem>
1746       </varlistentry>
1747
1748       <varlistentry>
1749         <term><varname>PrimaryReselectPolicy=</varname></term>
1750         <listitem>
1751           <para>Specifies the reselection policy for the primary slave.  This
1752           affects how the primary slave is chosen to become the active slave
1753           when failure of the active slave or recovery of the primary slave
1754           occurs. This option is designed to prevent flip-flopping between
1755           the primary slave and other slaves.  Possible values are
1756           <literal>always</literal>,
1757           <literal>better</literal> and
1758           <literal>failure</literal>.
1759           </para>
1760         </listitem>
1761       </varlistentry>
1762
1763       <varlistentry>
1764         <term><varname>ResendIGMP=</varname></term>
1765         <listitem>
1766           <para>Specifies the number of IGMP membership reports to be issued after
1767           a failover event. One membership report is issued immediately after
1768           the failover, subsequent packets are sent in each 200ms interval.
1769           The valid range is 0–255. Defaults to 1. A value of 0
1770           prevents the IGMP membership report from being issued in response
1771           to the failover event.
1772           </para>
1773         </listitem>
1774       </varlistentry>
1775
1776       <varlistentry>
1777         <term><varname>PacketsPerSlave=</varname></term>
1778         <listitem>
1779           <para>Specify the number of packets to transmit through a slave before
1780             moving to the next one. When set to 0, then a slave is chosen at
1781             random. The valid range is 0–65535. Defaults to 1. This option
1782             only has effect when in balance-rr mode.
1783           </para>
1784         </listitem>
1785       </varlistentry>
1786
1787       <varlistentry>
1788         <term><varname>GratuitousARP=</varname></term>
1789         <listitem>
1790           <para>Specify the number of peer notifications (gratuitous ARPs and
1791             unsolicited IPv6 Neighbor Advertisements) to be issued after a
1792             failover event.  As soon as the link is up on the new slave,
1793             a peer notification is sent on the  bonding device and each
1794             VLAN sub-device.  This is repeated at each link monitor interval
1795             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1796             greater than 1. The valid range is 0–255. The default value is 1.
1797             These options affect only the active-backup mode.
1798           </para>
1799         </listitem>
1800       </varlistentry>
1801
1802       <varlistentry>
1803         <term><varname>AllSlavesActive=</varname></term>
1804         <listitem>
1805           <para>Takes a boolean. Specifies that duplicate frames (received on inactive ports)
1806           should be dropped when false, or delivered when true. Normally, bonding will drop
1807           duplicate frames (received on inactive ports), which is desirable for
1808           most users. But there are some times it is nice to allow duplicate
1809           frames to be delivered. The default value is false (drop duplicate frames
1810           received on inactive ports).
1811           </para>
1812         </listitem>
1813       </varlistentry>
1814
1815       <varlistentry>
1816         <term><varname>DynamicTransmitLoadBalancing=</varname></term>
1817         <listitem>
1818           <para>Takes a boolean. Specifies if dynamic shuffling of flows is enabled. Applies only
1819           for balance-tlb mode. Defaults to unset.
1820           </para>
1821         </listitem>
1822       </varlistentry>
1823
1824       <varlistentry>
1825         <term><varname>MinLinks=</varname></term>
1826         <listitem>
1827           <para>Specifies the minimum number of links that must be active before
1828           asserting carrier. The default value is 0.
1829           </para>
1830         </listitem>
1831       </varlistentry>
1832     </variablelist>
1833
1834     <para>For more detail information see
1835     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1836     Linux Ethernet Bonding Driver HOWTO</ulink></para>
1837
1838   </refsect1>
1839
1840   <refsect1>
1841     <title>Examples</title>
1842     <example>
1843       <title>/etc/systemd/network/25-bridge.netdev</title>
1844
1845       <programlisting>[NetDev]
1846 Name=bridge0
1847 Kind=bridge</programlisting>
1848     </example>
1849
1850     <example>
1851       <title>/etc/systemd/network/25-vlan1.netdev</title>
1852
1853       <programlisting>[Match]
1854 Virtualization=no
1855
1856 [NetDev]
1857 Name=vlan1
1858 Kind=vlan
1859
1860 [VLAN]
1861 Id=1</programlisting>
1862     </example>
1863     <example>
1864       <title>/etc/systemd/network/25-ipip.netdev</title>
1865       <programlisting>[NetDev]
1866 Name=ipip-tun
1867 Kind=ipip
1868 MTUBytes=1480
1869
1870 [Tunnel]
1871 Local=192.168.223.238
1872 Remote=192.169.224.239
1873 TTL=64</programlisting>
1874     </example>
1875     <example>
1876       <title>/etc/systemd/network/1-fou-tunnel.netdev</title>
1877       <programlisting>[NetDev]
1878 Name=fou-tun
1879 Kind=fou
1880
1881 [FooOverUDP]
1882 Port=5555
1883 Protocol=4
1884       </programlisting>
1885     </example>
1886     <example>
1887       <title>/etc/systemd/network/25-fou-ipip.netdev</title>
1888       <programlisting>[NetDev]
1889 Name=ipip-tun
1890 Kind=ipip
1891
1892 [Tunnel]
1893 Independent=yes
1894 Local=10.65.208.212
1895 Remote=10.65.208.211
1896 FooOverUDP=yes
1897 FOUDestinationPort=5555
1898       </programlisting>
1899     </example>
1900     <example>
1901       <title>/etc/systemd/network/25-tap.netdev</title>
1902       <programlisting>[NetDev]
1903 Name=tap-test
1904 Kind=tap
1905
1906 [Tap]
1907 MultiQueue=yes
1908 PacketInfo=yes</programlisting> </example>
1909
1910     <example>
1911       <title>/etc/systemd/network/25-sit.netdev</title>
1912       <programlisting>[NetDev]
1913 Name=sit-tun
1914 Kind=sit
1915 MTUBytes=1480
1916
1917 [Tunnel]
1918 Local=10.65.223.238
1919 Remote=10.65.223.239</programlisting>
1920     </example>
1921
1922     <example>
1923       <title>/etc/systemd/network/25-6rd.netdev</title>
1924       <programlisting>[NetDev]
1925 Name=6rd-tun
1926 Kind=sit
1927 MTUBytes=1480
1928
1929 [Tunnel]
1930 Local=10.65.223.238
1931 IPv6RapidDeploymentPrefix=2602::/24</programlisting>
1932     </example>
1933
1934     <example>
1935       <title>/etc/systemd/network/25-gre.netdev</title>
1936       <programlisting>[NetDev]
1937 Name=gre-tun
1938 Kind=gre
1939 MTUBytes=1480
1940
1941 [Tunnel]
1942 Local=10.65.223.238
1943 Remote=10.65.223.239</programlisting>
1944     </example>
1945
1946     <example>
1947       <title>/etc/systemd/network/25-vti.netdev</title>
1948
1949       <programlisting>[NetDev]
1950 Name=vti-tun
1951 Kind=vti
1952 MTUBytes=1480
1953
1954 [Tunnel]
1955 Local=10.65.223.238
1956 Remote=10.65.223.239</programlisting>
1957     </example>
1958
1959     <example>
1960       <title>/etc/systemd/network/25-veth.netdev</title>
1961       <programlisting>[NetDev]
1962 Name=veth-test
1963 Kind=veth
1964
1965 [Peer]
1966 Name=veth-peer</programlisting>
1967     </example>
1968
1969     <example>
1970       <title>/etc/systemd/network/25-bond.netdev</title>
1971       <programlisting>[NetDev]
1972 Name=bond1
1973 Kind=bond
1974
1975 [Bond]
1976 Mode=802.3ad
1977 TransmitHashPolicy=layer3+4
1978 MIIMonitorSec=1s
1979 LACPTransmitRate=fast
1980 </programlisting>
1981     </example>
1982
1983     <example>
1984       <title>/etc/systemd/network/25-dummy.netdev</title>
1985       <programlisting>[NetDev]
1986 Name=dummy-test
1987 Kind=dummy
1988 MACAddress=12:34:56:78:9a:bc</programlisting>
1989     </example>
1990     <example>
1991       <title>/etc/systemd/network/25-vrf.netdev</title>
1992       <para>Create a VRF interface with table 42.</para>
1993       <programlisting>[NetDev]
1994 Name=vrf-test
1995 Kind=vrf
1996
1997 [VRF]
1998 Table=42</programlisting>
1999     </example>
2000
2001     <example>
2002       <title>/etc/systemd/network/25-macvtap.netdev</title>
2003       <para>Create a MacVTap device.</para>
2004       <programlisting>[NetDev]
2005 Name=macvtap-test
2006 Kind=macvtap
2007       </programlisting>
2008     </example>
2009     <example>
2010       <title>/etc/systemd/network/25-wireguard.netdev</title>
2011       <programlisting>[NetDev]
2012 Name=wg0
2013 Kind=wireguard
2014
2015 [WireGuard]
2016 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
2017 ListenPort=51820
2018
2019 [WireGuardPeer]
2020 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
2021 AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
2022 Endpoint=wireguard.example.com:51820</programlisting>
2023     </example>
2024   </refsect1>
2025   <refsect1>
2026     <title>See Also</title>
2027     <para>
2028       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
2029       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
2030       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
2031       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
2032     </para>
2033   </refsect1>
2034
2035 </refentry>