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   </refsect1>
 254
 255   <refsect1>
 256     <title>[NetDev] Section Options</title>
 257
 258     <para>The <literal>[NetDev]</literal> section accepts the
 259     following keys:</para>
 260
 261     <variablelist class='network-directives'>
 262       <varlistentry>
 263         <term><varname>Description=</varname></term>
 264         <listitem>
 265           <para>A free-form description of the netdev.</para>
 266         </listitem>
 267       </varlistentry>
 268       <varlistentry>
 269         <term><varname>Name=</varname></term>
 270         <listitem>
 271           <para>The interface name used when creating the netdev.
 272           This option is compulsory.</para>
 273         </listitem>
 274       </varlistentry>
 275       <varlistentry>
 276         <term><varname>Kind=</varname></term>
 277         <listitem>
 278           <para>The netdev kind. This option is compulsory. See the
 279           <literal>Supported netdev kinds</literal> section for the
 280           valid keys.</para>
 281         </listitem>
 282       </varlistentry>
 283       <varlistentry>
 284         <term><varname>MTUBytes=</varname></term>
 285         <listitem>
 286           <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M, G,
 287           are supported and are understood to the base of 1024. For <literal>tun</literal> or
 288           <literal>tap</literal> devices, <varname>MTUBytes=</varname> setting is not currently supported in
 289           <literal>[NetDev]</literal> section. Please specify it in <literal>[Link]</literal> section of
 290           corresponding
 291           <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 292           files.</para>
 293         </listitem>
 294       </varlistentry>
 295       <varlistentry>
 296         <term><varname>MACAddress=</varname></term>
 297         <listitem>
 298           <para>The MAC address to use for the device. For <literal>tun</literal> or <literal>tap</literal>
 299           devices, setting <varname>MACAddress=</varname> in the <literal>[NetDev]</literal> section is not
 300           supported. Please specify it in <literal>[Link]</literal> section of the corresponding
 301           <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 302           file. If this option is not set, <literal>vlan</literal> devices inherit the MAC address of the
 303           physical interface. For other kind of netdevs, if this option is not set, then MAC address is
 304           generated based on the interface name and the
 305           <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 306           </para>
 307         </listitem>
 308       </varlistentry>
 309     </variablelist>
 310   </refsect1>
 311
 312   <refsect1>
 313     <title>[Bridge] Section Options</title>
 314
 315     <para>The <literal>[Bridge]</literal> section only applies for
 316     netdevs of kind <literal>bridge</literal>, and accepts the
 317     following keys:</para>
 318
 319     <variablelist class='network-directives'>
 320       <varlistentry>
 321         <term><varname>HelloTimeSec=</varname></term>
 322         <listitem>
 323           <para>HelloTimeSec specifies the number of seconds between two hello packets
 324           sent out by the root bridge and the designated bridges. Hello packets are
 325           used to communicate information about the topology throughout the entire
 326           bridged local area network.</para>
 327         </listitem>
 328       </varlistentry>
 329       <varlistentry>
 330         <term><varname>MaxAgeSec=</varname></term>
 331         <listitem>
 332           <para>MaxAgeSec specifies the number of seconds of maximum message age.
 333           If the last seen (received) hello packet is more than this number of
 334           seconds old, the bridge in question will start the takeover procedure
 335           in attempt to become the Root Bridge itself.</para>
 336         </listitem>
 337       </varlistentry>
 338       <varlistentry>
 339         <term><varname>ForwardDelaySec=</varname></term>
 340         <listitem>
 341           <para>ForwardDelaySec specifies the number of seconds spent in each
 342           of the Listening and Learning states before the Forwarding state is entered.</para>
 343         </listitem>
 344       </varlistentry>
 345       <varlistentry>
 346         <term><varname>AgeingTimeSec=</varname></term>
 347         <listitem>
 348           <para>This specifies the number of seconds a MAC Address will be kept in
 349           the forwarding database after having a packet received from this MAC Address.</para>
 350         </listitem>
 351       </varlistentry>
 352       <varlistentry>
 353         <term><varname>Priority=</varname></term>
 354         <listitem>
 355           <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 356           means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 357         </listitem>
 358       </varlistentry>
 359       <varlistentry>
 360         <term><varname>GroupForwardMask=</varname></term>
 361         <listitem>
 362           <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 363           local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 364           is performed between the specified bitmask and the exponentiation of 2^X, the
 365           lower nibble of the last octet of the MAC address. For example, a value of 8
 366           would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 367         </listitem>
 368       </varlistentry>
 369       <varlistentry>
 370         <term><varname>DefaultPVID=</varname></term>
 371         <listitem>
 372           <para>This specifies the default port VLAN ID of a newly attached bridge port.
 373           Set this to an integer in the range 1–4094 or <literal>none</literal> to disable the PVID.</para>
 374         </listitem>
 375       </varlistentry>
 376       <varlistentry>
 377         <term><varname>MulticastQuerier=</varname></term>
 378         <listitem>
 379           <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 380           If enabled, the kernel will send general ICMP queries from a zero source address.
 381           This feature should allow faster convergence on startup, but it causes some
 382           multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 383           When unset, the kernel's default will be used.
 384           </para>
 385         </listitem>
 386       </varlistentry>
 387       <varlistentry>
 388         <term><varname>MulticastSnooping=</varname></term>
 389         <listitem>
 390           <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
 391           If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
 392           between hosts and multicast routers. When unset, the kernel's default will be used.
 393           </para>
 394         </listitem>
 395       </varlistentry>
 396       <varlistentry>
 397         <term><varname>VLANFiltering=</varname></term>
 398         <listitem>
 399           <para>Takes a boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 400           If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's default will be used.
 401           </para>
 402         </listitem>
 403       </varlistentry>
 404       <varlistentry>
 405         <term><varname>STP=</varname></term>
 406         <listitem>
 407           <para>Takes a boolean. This enables the bridge's Spanning Tree Protocol (STP).
 408           When unset, the kernel's default will be used.
 409           </para>
 410         </listitem>
 411       </varlistentry>
 412     </variablelist>
 413   </refsect1>
 414
 415   <refsect1>
 416     <title>[VLAN] Section Options</title>
 417
 418     <para>The <literal>[VLAN]</literal> section only applies for
 419     netdevs of kind <literal>vlan</literal>, and accepts the
 420     following key:</para>
 421
 422     <variablelist class='network-directives'>
 423       <varlistentry>
 424         <term><varname>Id=</varname></term>
 425         <listitem>
 426           <para>The VLAN ID to use. An integer in the range 0–4094.
 427           This option is compulsory.</para>
 428         </listitem>
 429       </varlistentry>
 430       <varlistentry>
 431         <term><varname>GVRP=</varname></term>
 432         <listitem>
 433           <para>Takes a boolean. The Generic VLAN Registration Protocol (GVRP) is a protocol that
 434           allows automatic learning of VLANs on a network.
 435           When unset, the kernel's default will be used.
 436           </para>
 437         </listitem>
 438       </varlistentry>
 439       <varlistentry>
 440         <term><varname>MVRP=</varname></term>
 441         <listitem>
 442           <para>Takes a boolean. Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 443           Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 444           for automatic configuration of VLAN information on switches. It was defined
 445           in the 802.1ak amendment to 802.1Q-2005. When unset, the kernel's default will be used.
 446           </para>
 447         </listitem>
 448       </varlistentry>
 449       <varlistentry>
 450         <term><varname>LooseBinding=</varname></term>
 451         <listitem>
 452           <para>Takes a boolean. The VLAN loose binding mode, in which only the operational state is passed
 453           from the parent to the associated VLANs, but the VLAN device state is not changed.
 454           When unset, the kernel's default will be used.</para>
 455         </listitem>
 456       </varlistentry>
 457       <varlistentry>
 458         <term><varname>ReorderHeader=</varname></term>
 459         <listitem>
 460           <para>Takes a boolean. The VLAN reorder header is set VLAN interfaces behave like physical interfaces.
 461           When unset, the kernel's default will be used.</para>
 462         </listitem>
 463       </varlistentry>
 464     </variablelist>
 465   </refsect1>
 466
 467   <refsect1>
 468     <title>[MACVLAN] Section Options</title>
 469
 470     <para>The <literal>[MACVLAN]</literal> section only applies for
 471     netdevs of kind <literal>macvlan</literal>, and accepts the
 472     following key:</para>
 473
 474     <variablelist class='network-directives'>
 475       <varlistentry>
 476         <term><varname>Mode=</varname></term>
 477         <listitem>
 478           <para>The MACVLAN mode to use. The supported options are
 479           <literal>private</literal>,
 480           <literal>vepa</literal>,
 481           <literal>bridge</literal>, and
 482           <literal>passthru</literal>.
 483           </para>
 484         </listitem>
 485       </varlistentry>
 486     </variablelist>
 487   </refsect1>
 488
 489   <refsect1>
 490     <title>[MACVTAP] Section Options</title>
 491
 492     <para>The <literal>[MACVTAP]</literal> section applies for
 493     netdevs of kind <literal>macvtap</literal> and accepts the
 494     same key as <literal>[MACVLAN]</literal>.</para>
 495   </refsect1>
 496
 497   <refsect1>
 498     <title>[IPVLAN] Section Options</title>
 499
 500     <para>The <literal>[IPVLAN]</literal> section only applies for
 501     netdevs of kind <literal>ipvlan</literal>, and accepts the
 502     following key:</para>
 503
 504     <variablelist class='network-directives'>
 505       <varlistentry>
 506         <term><varname>Mode=</varname></term>
 507         <listitem>
 508           <para>The IPVLAN mode to use. The supported options are
 509           <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 510           </para>
 511         </listitem>
 512       </varlistentry>
 513       <varlistentry>
 514         <term><varname>Flags=</varname></term>
 515         <listitem>
 516           <para>The IPVLAN flags to use. The supported options are
 517           <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 518           </para>
 519         </listitem>
 520       </varlistentry>
 521     </variablelist>
 522   </refsect1>
 523
 524   <refsect1>
 525     <title>[IPVTAP] Section Options</title>
 526
 527     <para>The <literal>[IPVTAP]</literal> section only applies for
 528     netdevs of kind <literal>ipvtap</literal> and accepts the
 529     same key as <literal>[IPVLAN]</literal>.</para>
 530   </refsect1>
 531
 532   <refsect1>
 533     <title>[VXLAN] Section Options</title>
 534
 535     <para>The <literal>[VXLAN]</literal> section only applies for
 536     netdevs of kind <literal>vxlan</literal>, and accepts the
 537     following keys:</para>
 538
 539     <variablelist class='network-directives'>
 540       <varlistentry>
 541         <term><varname>VNI=</varname></term>
 542         <listitem>
 543           <para>The VXLAN Network Identifier (or VXLAN Segment ID). Takes a number in the range 1-16777215.</para>
 544         </listitem>
 545       </varlistentry>
 546       <varlistentry>
 547         <term><varname>Remote=</varname></term>
 548         <listitem>
 549           <para>Configures destination IP address.</para>
 550         </listitem>
 551       </varlistentry>
 552       <varlistentry>
 553         <term><varname>Local=</varname></term>
 554         <listitem>
 555           <para>Configures local IP address.</para>
 556         </listitem>
 557       </varlistentry>
 558       <varlistentry>
 559         <term><varname>Group=</varname></term>
 560         <listitem>
 561           <para>Configures VXLAN multicast group IP address. All members of a VXLAN must use the same multicast group address.</para>
 562         </listitem>
 563       </varlistentry>
 564       <varlistentry>
 565         <term><varname>TOS=</varname></term>
 566         <listitem>
 567           <para>The Type Of Service byte value for a vxlan interface.</para>
 568         </listitem>
 569       </varlistentry>
 570       <varlistentry>
 571         <term><varname>TTL=</varname></term>
 572         <listitem>
 573           <para>A fixed Time To Live N on Virtual eXtensible Local Area Network packets.
 574           Takes <literal>inherit</literal> or a number in the range 0–255. 0 is a special
 575           value meaning inherit the inner protocol's TTL value. <literal>inherit</literal>
 576           means that it will inherit the outer protocol's TTL value.</para>
 577         </listitem>
 578       </varlistentry>
 579       <varlistentry>
 580         <term><varname>MacLearning=</varname></term>
 581         <listitem>
 582           <para>Takes a boolean. When true, enables dynamic MAC learning
 583           to discover remote MAC addresses.</para>
 584         </listitem>
 585       </varlistentry>
 586       <varlistentry>
 587         <term><varname>FDBAgeingSec=</varname></term>
 588         <listitem>
 589           <para>The lifetime of Forwarding Database entry learnt by
 590           the kernel, in seconds.</para>
 591         </listitem>
 592       </varlistentry>
 593       <varlistentry>
 594         <term><varname>MaximumFDBEntries=</varname></term>
 595         <listitem>
 596           <para>Configures maximum number of FDB entries.</para>
 597         </listitem>
 598       </varlistentry>
 599       <varlistentry>
 600         <term><varname>ReduceARPProxy=</varname></term>
 601         <listitem>
 602           <para>Takes a boolean. When true, bridge-connected VXLAN tunnel
 603           endpoint answers ARP requests from the local bridge on behalf
 604           of remote Distributed Overlay Virtual Ethernet
 605           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 606           (DVOE)</ulink> clients. Defaults to false.</para>
 607         </listitem>
 608       </varlistentry>
 609       <varlistentry>
 610         <term><varname>L2MissNotification=</varname></term>
 611         <listitem>
 612           <para>Takes a boolean. When true, enables netlink LLADDR miss
 613           notifications.</para>
 614         </listitem>
 615       </varlistentry>
 616       <varlistentry>
 617         <term><varname>L3MissNotification=</varname></term>
 618         <listitem>
 619           <para>Takes a boolean. When true, enables netlink IP address miss
 620           notifications.</para>
 621         </listitem>
 622       </varlistentry>
 623       <varlistentry>
 624         <term><varname>RouteShortCircuit=</varname></term>
 625         <listitem>
 626           <para>Takes a boolean. When true, route short circuiting is turned
 627           on.</para>
 628         </listitem>
 629       </varlistentry>
 630       <varlistentry>
 631         <term><varname>UDPChecksum=</varname></term>
 632         <listitem>
 633           <para>Takes a boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 634         </listitem>
 635       </varlistentry>
 636       <varlistentry>
 637         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 638         <listitem>
 639           <para>Takes a boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 640         </listitem>
 641       </varlistentry>
 642       <varlistentry>
 643         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 644         <listitem>
 645           <para>Takes a boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 646         </listitem>
 647       </varlistentry>
 648       <varlistentry>
 649         <term><varname>RemoteChecksumTx=</varname></term>
 650         <listitem>
 651           <para>Takes a boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 652         </listitem>
 653       </varlistentry>
 654       <varlistentry>
 655         <term><varname>RemoteChecksumRx=</varname></term>
 656         <listitem>
 657           <para>Takes a boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 658         </listitem>
 659       </varlistentry>
 660       <varlistentry>
 661         <term><varname>GroupPolicyExtension=</varname></term>
 662         <listitem>
 663           <para>Takes a boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 664           across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 665           <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 666           VXLAN Group Policy </ulink> document. Defaults to false.</para>
 667         </listitem>
 668       </varlistentry>
 669       <varlistentry>
 670         <term><varname>GenericProtocolExtension=</varname></term>
 671         <listitem>
 672           <para>Takes a boolean. When true, Generic Protocol Extension extends the existing VXLAN protocol
 673           to provide protocol typing, OAM, and versioning capabilities. For details about the VXLAN GPE
 674           Header, see the <ulink url="https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-07">
 675           Generic Protocol Extension for VXLAN </ulink> document. If destination port is not specified and
 676           Generic Protocol Extension is set then default port of 4790 is used. Defaults to false.</para>
 677         </listitem>
 678       </varlistentry>
 679       <varlistentry>
 680         <term><varname>DestinationPort=</varname></term>
 681         <listitem>
 682           <para>Configures the default destination UDP port on a per-device basis.
 683           If destination port is not specified then Linux kernel default will be used.
 684           Set destination port 4789 to get the IANA assigned value. If not set or if the
 685           destination port is assigned the empty string the default port of 4789 is used.</para>
 686         </listitem>
 687       </varlistentry>
 688       <varlistentry>
 689         <term><varname>PortRange=</varname></term>
 690         <listitem>
 691           <para>Configures VXLAN port range. VXLAN bases source
 692           UDP port based on flow to help the receiver to be able
 693           to load balance based on outer header flow. It
 694           restricts the port range to the normal UDP local
 695           ports, and allows overriding via configuration.</para>
 696         </listitem>
 697       </varlistentry>
 698       <varlistentry>
 699         <term><varname>FlowLabel=</varname></term>
 700         <listitem>
 701           <para>Specifies the flow label to use in outgoing packets.
 702           The valid range is 0-1048575.
 703           </para>
 704         </listitem>
 705       </varlistentry>
 706       <varlistentry>
 707         <term><varname>IPDoNotFragment=</varname></term>
 708         <listitem>
 709           <para>Allows to set the IPv4 Do not Fragment (DF) bit in outgoing packets, or to inherit its
 710           value from the IPv4 inner header. Takes a boolean value, or <literal>inherit</literal>. Set
 711           to <literal>inherit</literal> if the encapsulated protocol is IPv6. When unset, the kernel's
 712           default will be used.</para>
 713         </listitem>
 714       </varlistentry>
 715     </variablelist>
 716   </refsect1>
 717
 718   <refsect1>
 719     <title>[GENEVE] Section Options</title>
 720
 721     <para>The <literal>[GENEVE]</literal> section only applies for
 722     netdevs of kind <literal>geneve</literal>, and accepts the
 723     following keys:</para>
 724
 725     <variablelist class='network-directives'>
 726       <varlistentry>
 727         <term><varname>Id=</varname></term>
 728         <listitem>
 729           <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [0-16777215]. This field is mandatory.</para>
 730         </listitem>
 731       </varlistentry>
 732       <varlistentry>
 733         <term><varname>Remote=</varname></term>
 734         <listitem>
 735           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 736         </listitem>
 737       </varlistentry>
 738       <varlistentry>
 739         <term><varname>TOS=</varname></term>
 740         <listitem>
 741           <para>Specifies the TOS value to use in outgoing packets. Ranges [1-255].</para>
 742         </listitem>
 743       </varlistentry>
 744       <varlistentry>
 745         <term><varname>TTL=</varname></term>
 746         <listitem>
 747           <para>Accepts the same key in <literal>[VXLAN]</literal> section except when unset or
 748           set to 0, the kernel's default will be used meaning that packets TTL will be set from
 749           <filename>/proc/sys/net/ipv4/ip_default_ttl</filename>.</para>
 750         </listitem>
 751       </varlistentry>
 752       <varlistentry>
 753         <term><varname>UDPChecksum=</varname></term>
 754         <listitem>
 755           <para>Takes a boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.</para>
 756         </listitem>
 757       </varlistentry>
 758       <varlistentry>
 759         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 760         <listitem>
 761           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 762         </listitem>
 763       </varlistentry>
 764       <varlistentry>
 765         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 766         <listitem>
 767           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 768         </listitem>
 769       </varlistentry>
 770       <varlistentry>
 771         <term><varname>DestinationPort=</varname></term>
 772         <listitem>
 773           <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 774           port of 6081 is used.</para>
 775         </listitem>
 776       </varlistentry>
 777       <varlistentry>
 778         <term><varname>FlowLabel=</varname></term>
 779         <listitem>
 780           <para>Specifies the flow label to use in outgoing packets.</para>
 781         </listitem>
 782       </varlistentry>
 783       <varlistentry>
 784         <term><varname>IPDoNotFragment=</varname></term>
 785         <listitem>
 786           <para>Accepts the same key in <literal>[VXLAN]</literal> section.</para>
 787         </listitem>
 788       </varlistentry>
 789     </variablelist>
 790   </refsect1>
 791
 792   <refsect1>
 793     <title>[L2TP] Section Options</title>
 794
 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
 872   <refsect1>
 873     <title>[L2TPSession] Section Options</title>
 874
 875     <para>The <literal>[L2TPSession]</literal> section only applies for
 876     netdevs of kind <literal>l2tp</literal>, and accepts the
 877     following keys:</para>
 878     <variablelist class='network-directives'>
 879       <varlistentry>
 880         <term><varname>Name=</varname></term>
 881         <listitem>
 882           <para>Specifies the name of the session. This option is compulsory.</para>
 883         </listitem>
 884       </varlistentry>
 885       <varlistentry>
 886         <term><varname>SessionId=</varname></term>
 887         <listitem>
 888           <para>Specifies the session id. The value used must match the <literal>SessionId=</literal> value being used at the peer.
 889           Ranges a number between 1 and 4294967295). This option is compulsory.</para>
 890         </listitem>
 891       </varlistentry>
 892       <varlistentry>
 893         <term><varname>PeerSessionId=</varname></term>
 894         <listitem>
 895           <para>Specifies the peer session id. The value used must match the <literal>PeerSessionId=</literal> value being used at the peer.
 896           Ranges a number between 1 and 4294967295). This option is compulsory.</para>
 897         </listitem>
 898       </varlistentry>
 899       <varlistentry>
 900         <term><varname>Layer2SpecificHeader=</varname></term>
 901         <listitem>
 902           <para>Specifies layer2specific header type of the session. One of <literal>none</literal> or <literal>default</literal>. Defaults to <literal>default</literal>.</para>
 903         </listitem>
 904       </varlistentry>
 905     </variablelist>
 906   </refsect1>
 907
 908   <refsect1>
 909     <title>[MACsec] Section Options</title>
 910
 911     <para>The <literal>[MACsec]</literal> section only applies for network devices of kind
 912     <literal>macsec</literal>, and accepts the following keys:</para>
 913
 914     <variablelist class='network-directives'>
 915       <varlistentry>
 916         <term><varname>Port=</varname></term>
 917         <listitem>
 918           <para>Specifies the port to be used for the MACsec transmit channel. The port is used to make
 919           secure channel identifier (SCI). Takes a value between 1 and 65535. Defaults to unset.
 920           </para>
 921         </listitem>
 922       </varlistentry>
 923       <varlistentry>
 924         <term><varname>Encrypt=</varname></term>
 925         <listitem>
 926           <para>Takes a boolean. When true, enable encryption. Defaults to unset.</para>
 927         </listitem>
 928       </varlistentry>
 929     </variablelist>
 930   </refsect1>
 931
 932   <refsect1>
 933     <title>[MACsecReceiveChannel] Section Options</title>
 934     <para>The <literal>[MACsecReceiveChannel]</literal> section only applies for network devices of
 935     kind <literal>macsec</literal>, and accepts the following keys:</para>
 936
 937     <variablelist class='network-directives'>
 938       <varlistentry>
 939         <term><varname>Port=</varname></term>
 940         <listitem>
 941           <para>Specifies the port to be used for the MACsec receive channel. The port is used to make
 942           secure channel identifier (SCI). Takes a value between 1 and 65535. This option is
 943           compulsory, and is not set by default.</para>
 944         </listitem>
 945       </varlistentry>
 946       <varlistentry>
 947         <term><varname>MACAddress=</varname></term>
 948         <listitem>
 949           <para>Specifies the MAC address to be used for the MACsec receive channel. The MAC address
 950           used to make secure channel identifier (SCI). This option is compulsory, and is not set by
 951           default.</para>
 952         </listitem>
 953       </varlistentry>
 954     </variablelist>
 955   </refsect1>
 956
 957   <refsect1>
 958     <title>[MACsecTransmitAssociation] Section Options</title>
 959
 960     <para>The <literal>[MACsecTransmitAssociation]</literal> section only applies for network devices
 961     of kind <literal>macsec</literal>, and accepts the following keys:</para>
 962
 963     <variablelist class='network-directives'>
 964       <varlistentry>
 965         <term><varname>PacketNumber=</varname></term>
 966         <listitem>
 967           <para>Specifies the packet number to be used for replay protection and the construction of
 968           the initialization vector (along with the secure channel identifier [SCI]). Takes a value
 969           between 1-4,294,967,295. Defaults to unset.
 970           </para>
 971         </listitem>
 972       </varlistentry>
 973       <varlistentry>
 974         <term><varname>KeyId=</varname></term>
 975         <listitem>
 976           <para>Specifies the identification for the key. Takes a number between 0-255. This option
 977           is compulsory, and is not set by default.</para>
 978         </listitem>
 979       </varlistentry>
 980       <varlistentry>
 981         <term><varname>Key=</varname></term>
 982         <listitem>
 983           <para>Specifies the encryption key used in the transmission channel. The same key must be
 984           configured on the peer’s matching receive channel. This option is compulsory, and is not set
 985           by default. Takes a 128-bit key encoded in a hexadecimal string, for example
 986           <literal>dffafc8d7b9a43d5b9a3dfbbf6a30c16</literal>.</para>
 987         </listitem>
 988       </varlistentry>
 989       <varlistentry>
 990         <term><varname>KeyFile=</varname></term>
 991         <listitem>
 992           <para>Takes a absolute path to a file which contains a 128-bit key encoded in a hexadecimal
 993           string, which will be used in the transmission channel. When this option is specified,
 994           <varname>Key=</varname> is ignored. Note that the file must be readable by the user
 995           <literal>systemd-network</literal>, so it should be, e.g., owned by
 996           <literal>root:systemd-network</literal> with a <literal>0640</literal> file mode.</para>
 997         </listitem>
 998       </varlistentry>
 999       <varlistentry>
1000         <term><varname>Activate=</varname></term>
1001         <listitem>
1002           <para>Takes a boolean. If enabled, then the security association is activated. Defaults to
1003           unset.</para>
1004         </listitem>
1005       </varlistentry>
1006       <varlistentry>
1007         <term><varname>UseForEncoding=</varname></term>
1008         <listitem>
1009           <para>Takes a boolean. If enabled, then the security association is used for encoding. Only
1010           one <literal>[MACsecTransmitAssociation]</literal> section can enable this option. When enabled,
1011           <varname>Activate=yes</varname> is implied. Defaults to unset.</para>
1012         </listitem>
1013       </varlistentry>
1014     </variablelist>
1015   </refsect1>
1016
1017   <refsect1>
1018     <title>[MACsecReceiveAssociation] Section Options</title>
1019
1020     <para>The <literal>[MACsecReceiveAssociation]</literal> section only applies for
1021     network devices of kind <literal>macsec</literal>, and accepts the
1022     following keys:</para>
1023
1024     <variablelist class='network-directives'>
1025       <varlistentry>
1026         <term><varname>Port=</varname></term>
1027         <listitem>
1028           <para>Accepts the same key in <literal>[MACsecReceiveChannel]</literal> section.</para>
1029         </listitem>
1030       </varlistentry>
1031       <varlistentry>
1032         <term><varname>MACAddress=</varname></term>
1033         <listitem>
1034           <para>Accepts the same key in <literal>[MACsecReceiveChannel]</literal> section.</para>
1035         </listitem>
1036       </varlistentry>
1037       <varlistentry>
1038         <term><varname>PacketNumber=</varname></term>
1039         <listitem>
1040           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1041         </listitem>
1042       </varlistentry>
1043       <varlistentry>
1044         <term><varname>KeyId=</varname></term>
1045         <listitem>
1046           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1047         </listitem>
1048       </varlistentry>
1049       <varlistentry>
1050         <term><varname>Key=</varname></term>
1051         <listitem>
1052           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1053         </listitem>
1054       </varlistentry>
1055       <varlistentry>
1056         <term><varname>KeyFile=</varname></term>
1057         <listitem>
1058           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1059         </listitem>
1060       </varlistentry>
1061       <varlistentry>
1062         <term><varname>Activate=</varname></term>
1063         <listitem>
1064           <para>Accepts the same key in <literal>[MACsecTransmitAssociation]</literal> section.</para>
1065         </listitem>
1066       </varlistentry>
1067     </variablelist>
1068   </refsect1>
1069
1070   <refsect1>
1071     <title>[Tunnel] Section Options</title>
1072
1073     <para>The <literal>[Tunnel]</literal> section only applies for
1074     netdevs of kind
1075     <literal>ipip</literal>,
1076     <literal>sit</literal>,
1077     <literal>gre</literal>,
1078     <literal>gretap</literal>,
1079     <literal>ip6gre</literal>,
1080     <literal>ip6gretap</literal>,
1081     <literal>vti</literal>,
1082     <literal>vti6</literal>,
1083     <literal>ip6tnl</literal>, and
1084     <literal>erspan</literal> and accepts
1085     the following keys:</para>
1086
1087     <variablelist class='network-directives'>
1088       <varlistentry>
1089         <term><varname>Local=</varname></term>
1090         <listitem>
1091           <para>A static local address for tunneled packets. It must be an address on another interface of
1092           this host, or the special value <literal>any</literal>.</para>
1093         </listitem>
1094       </varlistentry>
1095       <varlistentry>
1096         <term><varname>Remote=</varname></term>
1097         <listitem>
1098           <para>The remote endpoint of the tunnel. Takes an IP address or the special value
1099           <literal>any</literal>.</para>
1100         </listitem>
1101       </varlistentry>
1102       <varlistentry>
1103         <term><varname>TOS=</varname></term>
1104         <listitem>
1105           <para>The Type Of Service byte value for a tunnel interface.
1106           For details about the TOS, see the
1107           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
1108           Service in the Internet Protocol Suite </ulink> document.
1109           </para>
1110         </listitem>
1111       </varlistentry>
1112       <varlistentry>
1113         <term><varname>TTL=</varname></term>
1114         <listitem>
1115           <para>A fixed Time To Live N on tunneled packets. N is a
1116           number in the range 1–255. 0 is a special value meaning that
1117           packets inherit the TTL value. The default value for IPv4
1118           tunnels is: inherit. The default value for IPv6 tunnels is
1119           64.</para>
1120         </listitem>
1121       </varlistentry>
1122       <varlistentry>
1123         <term><varname>DiscoverPathMTU=</varname></term>
1124         <listitem>
1125           <para>Takes a boolean. When true, enables Path MTU Discovery on
1126           the tunnel.</para>
1127         </listitem>
1128       </varlistentry>
1129       <varlistentry>
1130         <term><varname>IPv6FlowLabel=</varname></term>
1131         <listitem>
1132           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
1133           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
1134           RFC 2460</ulink>), which is used by a node to label packets of a flow.
1135           It is only used for IPv6 tunnels.
1136           A flow label of zero is used to indicate packets that have
1137           not been labeled.
1138           It can be configured to a value in the range 0–0xFFFFF, or be
1139           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
1140         </listitem>
1141       </varlistentry>
1142       <varlistentry>
1143         <term><varname>CopyDSCP=</varname></term>
1144         <listitem>
1145           <para>Takes a boolean. When true, the Differentiated Service Code
1146           Point (DSCP) field will be copied to the inner header from
1147           outer header during the decapsulation of an IPv6 tunnel
1148           packet. DSCP is a field in an IP packet that enables different
1149           levels of service to be assigned to network traffic.
1150           Defaults to <literal>no</literal>.
1151           </para>
1152         </listitem>
1153       </varlistentry>
1154       <varlistentry>
1155         <term><varname>EncapsulationLimit=</varname></term>
1156         <listitem>
1157           <para>The Tunnel Encapsulation Limit option specifies how many additional
1158           levels of encapsulation are permitted to be prepended to the packet.
1159           For example, a Tunnel Encapsulation Limit option containing a limit
1160           value of zero means that a packet carrying that option may not enter
1161           another tunnel before exiting the current tunnel.
1162           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
1163           The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
1164         </para>
1165         </listitem>
1166       </varlistentry>
1167       <varlistentry>
1168         <term><varname>Key=</varname></term>
1169         <listitem>
1170           <para>The <varname>Key=</varname> parameter specifies the same key to use in
1171           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
1172           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
1173           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
1174           and control path) in ip xfrm (framework used to implement IPsec protocol).
1175           See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
1176           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6,
1177           GRE, GRETAP, and ERSPAN tunnels.</para>
1178         </listitem>
1179       </varlistentry>
1180       <varlistentry>
1181         <term><varname>InputKey=</varname></term>
1182         <listitem>
1183           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
1184           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1185           and ERSPAN tunnels.</para>
1186         </listitem>
1187       </varlistentry>
1188       <varlistentry>
1189         <term><varname>OutputKey=</varname></term>
1190         <listitem>
1191           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
1192           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1193           and ERSPAN tunnels.</para>
1194         </listitem>
1195       </varlistentry>
1196       <varlistentry>
1197         <term><varname>Mode=</varname></term>
1198         <listitem>
1199           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
1200           modes
1201           <literal>ip6ip6</literal> for IPv6 over IPv6,
1202           <literal>ipip6</literal> for IPv4 over IPv6 or
1203           <literal>any</literal> for either.
1204           </para>
1205         </listitem>
1206       </varlistentry>
1207       <varlistentry>
1208         <term><varname>Independent=</varname></term>
1209         <listitem>
1210           <para>Takes a boolean. When true tunnel does not require .network file. Created as "tunnel@NONE".
1211           Defaults to <literal>false</literal>.
1212           </para>
1213         </listitem>
1214       </varlistentry>
1215       <varlistentry>
1216         <term><varname>AllowLocalRemote=</varname></term>
1217         <listitem>
1218           <para>Takes a boolean. When true allows tunnel traffic on <varname>ip6tnl</varname> devices where the remote endpoint is a local host address.
1219           When unset, the kernel's default will be used.
1220           </para>
1221         </listitem>
1222       </varlistentry>
1223       <varlistentry>
1224         <term><varname>FooOverUDP=</varname></term>
1225         <listitem>
1226           <para>Takes a boolean. Specifies whether <varname>FooOverUDP=</varname> tunnel is to be configured.
1227           Defaults to false. This takes effects only for IPIP, SIT, GRE, and GRETAP tunnels.
1228           For more detail information see
1229           <ulink url="https://lwn.net/Articles/614348">Foo over UDP</ulink></para>
1230         </listitem>
1231       </varlistentry>
1232       <varlistentry>
1233         <term><varname>FOUDestinationPort=</varname></term>
1234         <listitem>
1235           <para>This setting specifies the UDP destination port for encapsulation.
1236           This field is mandatory when <varname>FooOverUDP=yes</varname>, and is not set by default.</para>
1237         </listitem>
1238       </varlistentry>
1239       <varlistentry>
1240         <term><varname>FOUSourcePort=</varname></term>
1241         <listitem>
1242           <para>This setting specifies the UDP source port for encapsulation. Defaults to <constant>0</constant>
1243           — that is, the source port for packets is left to the network stack to decide.</para>
1244         </listitem>
1245       </varlistentry>
1246       <varlistentry>
1247         <term><varname>Encapsulation=</varname></term>
1248         <listitem>
1249           <para>Accepts the same key as in the <literal>[FooOverUDP]</literal> section.</para>
1250         </listitem>
1251       </varlistentry>
1252       <varlistentry>
1253         <term><varname>IPv6RapidDeploymentPrefix=</varname></term>
1254         <listitem>
1255           <para>Reconfigure the tunnel for <ulink url="https://tools.ietf.org/html/rfc5569">IPv6 Rapid
1256           Deployment</ulink>, also known as 6rd. The value is an ISP-specific IPv6 prefix with a non-zero length. Only
1257           applicable to SIT tunnels.</para>
1258         </listitem>
1259       </varlistentry>
1260       <varlistentry>
1261         <term><varname>ISATAP=</varname></term>
1262         <listitem>
1263           <para>Takes a boolean. If set, configures the tunnel as Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) tunnel.
1264           Only applicable to SIT tunnels. When unset, the kernel's default will be used.</para>
1265         </listitem>
1266       </varlistentry>
1267       <varlistentry>
1268         <term><varname>SerializeTunneledPackets=</varname></term>
1269         <listitem>
1270           <para>Takes a boolean. If set to yes, then packets are serialized. Only applies for GRE,
1271           GRETAP, and ERSPAN tunnels. When unset, the kernel's default will be used.
1272           </para>
1273         </listitem>
1274       </varlistentry>
1275       <varlistentry>
1276         <term><varname>ERSPANIndex=</varname></term>
1277         <listitem>
1278           <para>Specifies the ERSPAN index field for the interface, an integer in the range 1-1048575 associated with
1279           the ERSPAN traffic's source port and direction. This field is mandatory.
1280           </para>
1281         </listitem>
1282       </varlistentry>
1283     </variablelist>
1284   </refsect1>
1285
1286   <refsect1>
1287     <title>[FooOverUDP] Section Options</title>
1288
1289     <para>The <literal>[FooOverUDP]</literal> section only applies for
1290     netdevs of kind <literal>fou</literal> and accepts the
1291     following keys:</para>
1292
1293     <variablelist class='network-directives'>
1294       <varlistentry>
1295         <term><varname>Encapsulation=</varname></term>
1296         <listitem>
1297           <para>Specifies the encapsulation mechanism used to store networking packets of various protocols inside the UDP packets. Supports the following values:
1298
1299           <literal>FooOverUDP</literal> provides the simplest no frills model of UDP encapsulation, it simply encapsulates
1300           packets directly in the UDP payload.
1301           <literal>GenericUDPEncapsulation</literal> is a generic and extensible encapsulation, it allows encapsulation of packets for any IP
1302           protocol and optional data as part of the encapsulation.
1303           For more detailed information see <ulink url="https://lwn.net/Articles/615044">Generic UDP Encapsulation</ulink>.
1304           Defaults to <literal>FooOverUDP</literal>.
1305           </para>
1306         </listitem>
1307       </varlistentry>
1308       <varlistentry>
1309         <term><varname>Port=</varname></term>
1310         <listitem>
1311           <para>Specifies the port number, where the IP encapsulation packets will arrive. Please take note that the packets
1312           will arrive with the encapsulation will be removed. Then they will be manually fed back into the network stack, and sent ahead
1313           for delivery to the real destination. This option is mandatory.</para>
1314         </listitem>
1315       </varlistentry>
1316       <varlistentry>
1317         <term><varname>PeerPort=</varname></term>
1318         <listitem>
1319           <para>Specifies the peer port number. Defaults to unset. Note that when peer port is set <literal>Peer=</literal> address is mandotory.</para>
1320         </listitem>
1321       </varlistentry>
1322       <varlistentry>
1323         <term><varname>Protocol=</varname></term>
1324         <listitem>
1325           <para>The <varname>Protocol=</varname> specifies the protocol number of the packets arriving
1326           at the UDP port. When <varname>Encapsulation=FooOverUDP</varname>, this field is mandatory
1327           and is not set by default. Takes an IP protocol name such as <literal>gre</literal> or
1328           <literal>ipip</literal>, or an integer within the range 1-255. When
1329           <varname>Encapsulation=GenericUDPEncapsulation</varname>, this must not be specified.</para>
1330         </listitem>
1331       </varlistentry>
1332       <varlistentry>
1333         <term><varname>Peer=</varname></term>
1334         <listitem>
1335           <para>Configures peer IP address. Note that when peer address is set <literal>PeerPort=</literal> is mandotory.</para>
1336         </listitem>
1337       </varlistentry>
1338       <varlistentry>
1339         <term><varname>Local=</varname></term>
1340         <listitem>
1341           <para>Configures local IP address.</para>
1342         </listitem>
1343       </varlistentry>
1344     </variablelist>
1345   </refsect1>
1346
1347   <refsect1>
1348     <title>[Peer] Section Options</title>
1349
1350     <para>The <literal>[Peer]</literal> section only applies for
1351     netdevs of kind <literal>veth</literal> and accepts the
1352     following keys:</para>
1353
1354     <variablelist class='network-directives'>
1355       <varlistentry>
1356         <term><varname>Name=</varname></term>
1357         <listitem>
1358           <para>The interface name used when creating the netdev.
1359           This option is compulsory.</para>
1360         </listitem>
1361       </varlistentry>
1362       <varlistentry>
1363         <term><varname>MACAddress=</varname></term>
1364         <listitem>
1365           <para>The peer MACAddress, if not set, it is generated in
1366           the same way as the MAC address of the main
1367           interface.</para>
1368         </listitem>
1369       </varlistentry>
1370     </variablelist>
1371   </refsect1>
1372
1373   <refsect1>
1374     <title>[VXCAN] Section Options</title>
1375
1376     <para>The <literal>[VXCAN]</literal> section only applies for
1377     netdevs of kind <literal>vxcan</literal> and accepts the
1378     following key:</para>
1379
1380     <variablelist class='network-directives'>
1381       <varlistentry>
1382         <term><varname>Peer=</varname></term>
1383         <listitem>
1384           <para>The peer interface name used when creating the netdev.
1385           This option is compulsory.</para>
1386         </listitem>
1387       </varlistentry>
1388     </variablelist>
1389   </refsect1>
1390
1391   <refsect1>
1392     <title>[Tun] Section Options</title>
1393
1394     <para>The <literal>[Tun]</literal> section only applies for
1395     netdevs of kind <literal>tun</literal>, and accepts the following
1396     keys:</para>
1397
1398     <variablelist class='network-directives'>
1399       <varlistentry>
1400         <term><varname>MultiQueue=</varname></term>
1401         <listitem><para>Takes a boolean. Configures whether
1402         to use multiple file descriptors (queues) to parallelize
1403         packets sending and receiving. Defaults to
1404         <literal>no</literal>.</para>
1405         </listitem>
1406       </varlistentry>
1407       <varlistentry>
1408         <term><varname>PacketInfo=</varname></term>
1409         <listitem><para>Takes a boolean. Configures whether
1410         packets should be prepended with four extra bytes (two flag
1411         bytes and two protocol bytes). If disabled, it indicates that
1412         the packets will be pure IP packets. Defaults to
1413         <literal>no</literal>.</para>
1414         </listitem>
1415       </varlistentry>
1416       <varlistentry>
1417         <term><varname>VNetHeader=</varname></term>
1418         <listitem><para>Takes a boolean. Configures
1419         IFF_VNET_HDR flag for a tun or tap device. It allows sending
1420         and receiving larger Generic Segmentation Offload (GSO)
1421         packets. This may increase throughput significantly.
1422         Defaults to
1423         <literal>no</literal>.</para>
1424         </listitem>
1425       </varlistentry>
1426       <varlistentry>
1427         <term><varname>User=</varname></term>
1428         <listitem><para>User to grant access to the
1429         <filename>/dev/net/tun</filename> device.</para>
1430         </listitem>
1431       </varlistentry>
1432       <varlistentry>
1433         <term><varname>Group=</varname></term>
1434         <listitem><para>Group to grant access to the
1435         <filename>/dev/net/tun</filename> device.</para>
1436         </listitem>
1437       </varlistentry>
1438     </variablelist>
1439   </refsect1>
1440
1441   <refsect1>
1442     <title>[Tap] Section Options</title>
1443
1444     <para>The <literal>[Tap]</literal> section only applies for
1445     netdevs of kind <literal>tap</literal>, and accepts the same keys
1446     as the <literal>[Tun]</literal> section.</para>
1447   </refsect1>
1448
1449   <refsect1>
1450     <title>[WireGuard] Section Options</title>
1451
1452     <para>The <literal>[WireGuard]</literal> section accepts the following
1453     keys:</para>
1454
1455     <variablelist class='network-directives'>
1456       <varlistentry>
1457         <term><varname>PrivateKey=</varname></term>
1458         <listitem>
1459           <para>The Base64 encoded private key for the interface. It can be
1460           generated using the <command>wg genkey</command> command
1461           (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1462           This option or <varname>PrivateKeyFile=</varname> is mandatory to use WireGuard.
1463           Note that because this information is secret, you may want to set
1464           the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1465           with a <literal>0640</literal> file mode.</para>
1466         </listitem>
1467       </varlistentry>
1468       <varlistentry>
1469         <term><varname>PrivateKeyFile=</varname></term>
1470         <listitem>
1471           <para>Takes an absolute path to a file which contains the Base64 encoded private key for the interface.
1472           When this option is specified, then <varname>PrivateKey=</varname> is ignored.
1473           Note that the file must be readable by the user <literal>systemd-network</literal>, so it
1474           should be, e.g., owned by <literal>root:systemd-network</literal> with a
1475           <literal>0640</literal> file mode.</para>
1476         </listitem>
1477       </varlistentry>
1478       <varlistentry>
1479         <term><varname>ListenPort=</varname></term>
1480         <listitem>
1481           <para>Sets UDP port for listening. Takes either value between 1 and 65535
1482           or <literal>auto</literal>. If <literal>auto</literal> is specified,
1483           the port is automatically generated based on interface name.
1484           Defaults to <literal>auto</literal>.</para>
1485         </listitem>
1486       </varlistentry>
1487       <varlistentry>
1488         <term><varname>FirewallMark=</varname></term>
1489         <listitem>
1490           <para>Sets a firewall mark on outgoing WireGuard packets from this interface. Takes a number between 1 and 4294967295.</para>
1491         </listitem>
1492       </varlistentry>
1493     </variablelist>
1494   </refsect1>
1495
1496   <refsect1>
1497     <title>[WireGuardPeer] Section Options</title>
1498
1499     <para>The <literal>[WireGuardPeer]</literal> section accepts the following
1500     keys:</para>
1501
1502     <variablelist class='network-directives'>
1503       <varlistentry>
1504         <term><varname>PublicKey=</varname></term>
1505         <listitem>
1506           <para>Sets a Base64 encoded public key calculated by <command>wg pubkey</command>
1507           (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1508           from a private key, and usually transmitted out of band to the
1509           author of the configuration file. This option is mandatory for this
1510           section.</para>
1511         </listitem>
1512       </varlistentry>
1513       <varlistentry>
1514         <term><varname>PresharedKey=</varname></term>
1515         <listitem>
1516           <para>Optional preshared key for the interface. It can be generated
1517           by the <command>wg genpsk</command> command. This option adds an
1518           additional layer of symmetric-key cryptography to be mixed into the
1519           already existing public-key cryptography, for post-quantum
1520           resistance.
1521           Note that because this information is secret, you may want to set
1522           the permissions of the .netdev file to be owned by <literal>root:systemd-networkd</literal>
1523           with a <literal>0640</literal> file mode.</para>
1524         </listitem>
1525       </varlistentry>
1526       <varlistentry>
1527         <term><varname>PresharedKeyFile=</varname></term>
1528         <listitem>
1529           <para>Takes an absolute path to a file which contains the Base64 encoded preshared key for the
1530           peer. When this option is specified, then <varname>PresharedKey=</varname> is ignored.
1531           Note that the file must be readable by the user <literal>systemd-network</literal>, so it
1532           should be, e.g., owned by <literal>root:systemd-network</literal> with a
1533           <literal>0640</literal> file mode.</para>
1534         </listitem>
1535       </varlistentry>
1536       <varlistentry>
1537         <term><varname>AllowedIPs=</varname></term>
1538         <listitem>
1539           <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks
1540           from which this peer is allowed to send incoming traffic and to
1541           which outgoing traffic for this peer is directed. The catch-all
1542           0.0.0.0/0 may be specified for matching all IPv4 addresses, and
1543           ::/0 may be specified for matching all IPv6 addresses. </para>
1544         </listitem>
1545       </varlistentry>
1546       <varlistentry>
1547         <term><varname>Endpoint=</varname></term>
1548         <listitem>
1549           <para>Sets an endpoint IP address or hostname, followed by a colon, and then
1550           a port number. This endpoint will be updated automatically once to
1551           the most recent source IP address and port of correctly
1552           authenticated packets from the peer at configuration time.</para>
1553         </listitem>
1554       </varlistentry>
1555       <varlistentry>
1556         <term><varname>PersistentKeepalive=</varname></term>
1557         <listitem>
1558           <para>Sets a seconds interval, between 1 and 65535 inclusive, of how often
1559           to send an authenticated empty packet to the peer for the purpose
1560           of keeping a stateful firewall or NAT mapping valid persistently.
1561           For example, if the interface very rarely sends traffic, but it
1562           might at anytime receive traffic from a peer, and it is behind NAT,
1563           the interface might benefit from having a persistent keepalive
1564           interval of 25 seconds. If set to 0 or "off", this option is
1565           disabled. By default or when unspecified, this option is off.
1566           Most users will not need this.</para>
1567         </listitem>
1568       </varlistentry>
1569     </variablelist>
1570   </refsect1>
1571
1572   <refsect1>
1573     <title>[Bond] Section Options</title>
1574
1575     <para>The <literal>[Bond]</literal> section accepts the following
1576     key:</para>
1577
1578     <variablelist class='network-directives'>
1579       <varlistentry>
1580         <term><varname>Mode=</varname></term>
1581         <listitem>
1582           <para>Specifies one of the bonding policies. The default is
1583           <literal>balance-rr</literal> (round robin). Possible values are
1584           <literal>balance-rr</literal>,
1585           <literal>active-backup</literal>,
1586           <literal>balance-xor</literal>,
1587           <literal>broadcast</literal>,
1588           <literal>802.3ad</literal>,
1589           <literal>balance-tlb</literal>, and
1590           <literal>balance-alb</literal>.
1591           </para>
1592         </listitem>
1593       </varlistentry>
1594
1595       <varlistentry>
1596         <term><varname>TransmitHashPolicy=</varname></term>
1597         <listitem>
1598           <para>Selects the transmit hash policy to use for slave
1599           selection in balance-xor, 802.3ad, and tlb modes. Possible
1600           values are
1601           <literal>layer2</literal>,
1602           <literal>layer3+4</literal>,
1603           <literal>layer2+3</literal>,
1604           <literal>encap2+3</literal>, and
1605           <literal>encap3+4</literal>.
1606           </para>
1607         </listitem>
1608       </varlistentry>
1609
1610       <varlistentry>
1611         <term><varname>LACPTransmitRate=</varname></term>
1612         <listitem>
1613           <para>Specifies the rate with which link partner transmits
1614           Link Aggregation Control Protocol Data Unit packets in
1615           802.3ad mode. Possible values are <literal>slow</literal>,
1616           which requests partner to transmit LACPDUs every 30 seconds,
1617           and <literal>fast</literal>, which requests partner to
1618           transmit LACPDUs every second. The default value is
1619           <literal>slow</literal>.</para>
1620         </listitem>
1621       </varlistentry>
1622
1623       <varlistentry>
1624         <term><varname>MIIMonitorSec=</varname></term>
1625         <listitem>
1626           <para>Specifies the frequency that Media Independent
1627           Interface link monitoring will occur. A value of zero
1628           disables MII link monitoring. This value is rounded down to
1629           the nearest millisecond. The default value is 0.</para>
1630         </listitem>
1631       </varlistentry>
1632
1633       <varlistentry>
1634         <term><varname>UpDelaySec=</varname></term>
1635         <listitem>
1636           <para>Specifies the delay before a link is enabled after a
1637           link up status has been detected. This value is rounded down
1638           to a multiple of MIIMonitorSec. The default value is
1639           0.</para>
1640         </listitem>
1641       </varlistentry>
1642
1643       <varlistentry>
1644         <term><varname>DownDelaySec=</varname></term>
1645         <listitem>
1646           <para>Specifies the delay before a link is disabled after a
1647           link down status has been detected. This value is rounded
1648           down to a multiple of MIIMonitorSec. The default value is
1649           0.</para>
1650         </listitem>
1651       </varlistentry>
1652
1653       <varlistentry>
1654         <term><varname>LearnPacketIntervalSec=</varname></term>
1655         <listitem>
1656           <para>Specifies the number of seconds between instances where the bonding
1657           driver sends learning packets to each slave peer switch.
1658           The valid range is 1–0x7fffffff; the default value is 1. This option
1659           has an effect only for the balance-tlb and balance-alb modes.</para>
1660         </listitem>
1661       </varlistentry>
1662
1663       <varlistentry>
1664         <term><varname>AdSelect=</varname></term>
1665         <listitem>
1666           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
1667           <literal>stable</literal>,
1668           <literal>bandwidth</literal> and
1669           <literal>count</literal>.
1670           </para>
1671         </listitem>
1672       </varlistentry>
1673
1674       <varlistentry>
1675         <term><varname>AdActorSystemPriority=</varname></term>
1676         <listitem>
1677           <para>Specifies the 802.3ad actor system priority. Ranges [1-65535].</para>
1678         </listitem>
1679       </varlistentry>
1680
1681       <varlistentry>
1682         <term><varname>AdUserPortKey=</varname></term>
1683         <listitem>
1684           <para>Specifies the 802.3ad user defined portion of the port key. Ranges [0-1023].</para>
1685         </listitem>
1686       </varlistentry>
1687
1688       <varlistentry>
1689         <term><varname>AdActorSystem=</varname></term>
1690         <listitem>
1691           <para>Specifies the 802.3ad system mac address. This can not be either NULL or Multicast.</para>
1692         </listitem>
1693       </varlistentry>
1694
1695       <varlistentry>
1696         <term><varname>FailOverMACPolicy=</varname></term>
1697         <listitem>
1698           <para>Specifies whether the active-backup mode should set all slaves to
1699           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1700           bond's MAC address in accordance with the selected policy. The default policy is none.
1701           Possible values are
1702           <literal>none</literal>,
1703           <literal>active</literal> and
1704           <literal>follow</literal>.
1705           </para>
1706         </listitem>
1707       </varlistentry>
1708
1709       <varlistentry>
1710         <term><varname>ARPValidate=</varname></term>
1711         <listitem>
1712           <para>Specifies whether or not ARP probes and replies should be
1713           validated in any mode that supports ARP monitoring, or whether
1714           non-ARP traffic should be filtered (disregarded) for link
1715           monitoring purposes. Possible values are
1716           <literal>none</literal>,
1717           <literal>active</literal>,
1718           <literal>backup</literal> and
1719           <literal>all</literal>.
1720           </para>
1721         </listitem>
1722       </varlistentry>
1723
1724       <varlistentry>
1725         <term><varname>ARPIntervalSec=</varname></term>
1726         <listitem>
1727           <para>Specifies the ARP link monitoring frequency in milliseconds.
1728           A value of 0 disables ARP monitoring. The default value is 0.
1729           </para>
1730         </listitem>
1731       </varlistentry>
1732
1733       <varlistentry>
1734         <term><varname>ARPIPTargets=</varname></term>
1735         <listitem>
1736           <para>Specifies the IP addresses to use as ARP monitoring peers when
1737           ARPIntervalSec is greater than 0. These are the targets of the ARP request
1738           sent to determine the health of the link to the targets.
1739           Specify these values in IPv4 dotted decimal format. At least one IP
1740           address must be given for ARP monitoring to function. The
1741           maximum number of targets that can be specified is 16. The
1742           default value is no IP addresses.
1743           </para>
1744         </listitem>
1745       </varlistentry>
1746
1747       <varlistentry>
1748         <term><varname>ARPAllTargets=</varname></term>
1749         <listitem>
1750           <para>Specifies the quantity of ARPIPTargets that must be reachable
1751           in order for the ARP monitor to consider a slave as being up.
1752           This option affects only active-backup mode for slaves with
1753           ARPValidate enabled. Possible values are
1754           <literal>any</literal> and
1755           <literal>all</literal>.
1756           </para>
1757         </listitem>
1758       </varlistentry>
1759
1760       <varlistentry>
1761         <term><varname>PrimaryReselectPolicy=</varname></term>
1762         <listitem>
1763           <para>Specifies the reselection policy for the primary slave.  This
1764           affects how the primary slave is chosen to become the active slave
1765           when failure of the active slave or recovery of the primary slave
1766           occurs. This option is designed to prevent flip-flopping between
1767           the primary slave and other slaves.  Possible values are
1768           <literal>always</literal>,
1769           <literal>better</literal> and
1770           <literal>failure</literal>.
1771           </para>
1772         </listitem>
1773       </varlistentry>
1774
1775       <varlistentry>
1776         <term><varname>ResendIGMP=</varname></term>
1777         <listitem>
1778           <para>Specifies the number of IGMP membership reports to be issued after
1779           a failover event. One membership report is issued immediately after
1780           the failover, subsequent packets are sent in each 200ms interval.
1781           The valid range is 0–255. Defaults to 1. A value of 0
1782           prevents the IGMP membership report from being issued in response
1783           to the failover event.
1784           </para>
1785         </listitem>
1786       </varlistentry>
1787
1788       <varlistentry>
1789         <term><varname>PacketsPerSlave=</varname></term>
1790         <listitem>
1791           <para>Specify the number of packets to transmit through a slave before
1792           moving to the next one. When set to 0, then a slave is chosen at
1793           random. The valid range is 0–65535. Defaults to 1. This option
1794           only has effect when in balance-rr mode.
1795           </para>
1796         </listitem>
1797       </varlistentry>
1798
1799       <varlistentry>
1800         <term><varname>GratuitousARP=</varname></term>
1801         <listitem>
1802           <para>Specify the number of peer notifications (gratuitous ARPs and
1803           unsolicited IPv6 Neighbor Advertisements) to be issued after a
1804           failover event.  As soon as the link is up on the new slave,
1805           a peer notification is sent on the  bonding device and each
1806           VLAN sub-device.  This is repeated at each link monitor interval
1807           (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1808           greater than 1. The valid range is 0–255. The default value is 1.
1809           These options affect only the active-backup mode.
1810           </para>
1811         </listitem>
1812       </varlistentry>
1813
1814       <varlistentry>
1815         <term><varname>AllSlavesActive=</varname></term>
1816         <listitem>
1817           <para>Takes a boolean. Specifies that duplicate frames (received on inactive ports)
1818           should be dropped when false, or delivered when true. Normally, bonding will drop
1819           duplicate frames (received on inactive ports), which is desirable for
1820           most users. But there are some times it is nice to allow duplicate
1821           frames to be delivered. The default value is false (drop duplicate frames
1822           received on inactive ports).
1823           </para>
1824         </listitem>
1825       </varlistentry>
1826
1827       <varlistentry>
1828         <term><varname>DynamicTransmitLoadBalancing=</varname></term>
1829         <listitem>
1830           <para>Takes a boolean. Specifies if dynamic shuffling of flows is enabled. Applies only
1831           for balance-tlb mode. Defaults to unset.
1832           </para>
1833         </listitem>
1834       </varlistentry>
1835
1836       <varlistentry>
1837         <term><varname>MinLinks=</varname></term>
1838         <listitem>
1839           <para>Specifies the minimum number of links that must be active before
1840           asserting carrier. The default value is 0.
1841           </para>
1842         </listitem>
1843       </varlistentry>
1844     </variablelist>
1845
1846     <para>For more detail information see
1847     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1848     Linux Ethernet Bonding Driver HOWTO</ulink></para>
1849   </refsect1>
1850
1851   <refsect1>
1852     <title>[VRF] Section Options</title>
1853     <para>The <literal>[VRF]</literal> section only applies for
1854     netdevs of kind <literal>vrf</literal> and accepts the
1855     following key:</para>
1856
1857     <variablelist class='network-directives'>
1858       <varlistentry>
1859         <term><varname>Table=</varname></term>
1860         <listitem>
1861           <para>The numeric routing table identifier. This option is compulsory.</para>
1862         </listitem>
1863       </varlistentry>
1864     </variablelist>
1865   </refsect1>
1866
1867   <refsect1>
1868     <title>Examples</title>
1869     <example>
1870       <title>/etc/systemd/network/25-bridge.netdev</title>
1871
1872       <programlisting>[NetDev]
1873 Name=bridge0
1874 Kind=bridge</programlisting>
1875     </example>
1876
1877     <example>
1878       <title>/etc/systemd/network/25-vlan1.netdev</title>
1879
1880       <programlisting>[Match]
1881 Virtualization=no
1882
1883 [NetDev]
1884 Name=vlan1
1885 Kind=vlan
1886
1887 [VLAN]
1888 Id=1</programlisting>
1889     </example>
1890     <example>
1891       <title>/etc/systemd/network/25-ipip.netdev</title>
1892       <programlisting>[NetDev]
1893 Name=ipip-tun
1894 Kind=ipip
1895 MTUBytes=1480
1896
1897 [Tunnel]
1898 Local=192.168.223.238
1899 Remote=192.169.224.239
1900 TTL=64</programlisting>
1901     </example>
1902     <example>
1903       <title>/etc/systemd/network/1-fou-tunnel.netdev</title>
1904       <programlisting>[NetDev]
1905 Name=fou-tun
1906 Kind=fou
1907
1908 [FooOverUDP]
1909 Port=5555
1910 Protocol=4
1911       </programlisting>
1912     </example>
1913     <example>
1914       <title>/etc/systemd/network/25-fou-ipip.netdev</title>
1915       <programlisting>[NetDev]
1916 Name=ipip-tun
1917 Kind=ipip
1918
1919 [Tunnel]
1920 Independent=yes
1921 Local=10.65.208.212
1922 Remote=10.65.208.211
1923 FooOverUDP=yes
1924 FOUDestinationPort=5555
1925       </programlisting>
1926     </example>
1927     <example>
1928       <title>/etc/systemd/network/25-tap.netdev</title>
1929       <programlisting>[NetDev]
1930 Name=tap-test
1931 Kind=tap
1932
1933 [Tap]
1934 MultiQueue=yes
1935 PacketInfo=yes</programlisting> </example>
1936
1937     <example>
1938       <title>/etc/systemd/network/25-sit.netdev</title>
1939       <programlisting>[NetDev]
1940 Name=sit-tun
1941 Kind=sit
1942 MTUBytes=1480
1943
1944 [Tunnel]
1945 Local=10.65.223.238
1946 Remote=10.65.223.239</programlisting>
1947     </example>
1948
1949     <example>
1950       <title>/etc/systemd/network/25-6rd.netdev</title>
1951       <programlisting>[NetDev]
1952 Name=6rd-tun
1953 Kind=sit
1954 MTUBytes=1480
1955
1956 [Tunnel]
1957 Local=10.65.223.238
1958 IPv6RapidDeploymentPrefix=2602::/24</programlisting>
1959     </example>
1960
1961     <example>
1962       <title>/etc/systemd/network/25-gre.netdev</title>
1963       <programlisting>[NetDev]
1964 Name=gre-tun
1965 Kind=gre
1966 MTUBytes=1480
1967
1968 [Tunnel]
1969 Local=10.65.223.238
1970 Remote=10.65.223.239</programlisting>
1971     </example>
1972
1973     <example>
1974       <title>/etc/systemd/network/25-vti.netdev</title>
1975
1976       <programlisting>[NetDev]
1977 Name=vti-tun
1978 Kind=vti
1979 MTUBytes=1480
1980
1981 [Tunnel]
1982 Local=10.65.223.238
1983 Remote=10.65.223.239</programlisting>
1984     </example>
1985
1986     <example>
1987       <title>/etc/systemd/network/25-veth.netdev</title>
1988       <programlisting>[NetDev]
1989 Name=veth-test
1990 Kind=veth
1991
1992 [Peer]
1993 Name=veth-peer</programlisting>
1994     </example>
1995
1996     <example>
1997       <title>/etc/systemd/network/25-bond.netdev</title>
1998       <programlisting>[NetDev]
1999 Name=bond1
2000 Kind=bond
2001
2002 [Bond]
2003 Mode=802.3ad
2004 TransmitHashPolicy=layer3+4
2005 MIIMonitorSec=1s
2006 LACPTransmitRate=fast
2007 </programlisting>
2008     </example>
2009
2010     <example>
2011       <title>/etc/systemd/network/25-dummy.netdev</title>
2012       <programlisting>[NetDev]
2013 Name=dummy-test
2014 Kind=dummy
2015 MACAddress=12:34:56:78:9a:bc</programlisting>
2016     </example>
2017     <example>
2018       <title>/etc/systemd/network/25-vrf.netdev</title>
2019       <para>Create a VRF interface with table 42.</para>
2020       <programlisting>[NetDev]
2021 Name=vrf-test
2022 Kind=vrf
2023
2024 [VRF]
2025 Table=42</programlisting>
2026     </example>
2027
2028     <example>
2029       <title>/etc/systemd/network/25-macvtap.netdev</title>
2030       <para>Create a MacVTap device.</para>
2031       <programlisting>[NetDev]
2032 Name=macvtap-test
2033 Kind=macvtap
2034       </programlisting>
2035     </example>
2036     <example>
2037       <title>/etc/systemd/network/25-wireguard.netdev</title>
2038       <programlisting>[NetDev]
2039 Name=wg0
2040 Kind=wireguard
2041
2042 [WireGuard]
2043 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
2044 ListenPort=51820
2045
2046 [WireGuardPeer]
2047 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
2048 AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
2049 Endpoint=wireguard.example.com:51820</programlisting>
2050     </example>
2051   </refsect1>
2052
2053   <refsect1>
2054     <title>See Also</title>
2055     <para>
2056       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
2057       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
2058       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
2059       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
2060     </para>
2061   </refsect1>
2062
2063 </refentry>