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>A plain ini-style text file that encodes configuration about a virtual network device, used by
  31     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  32     See <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  33     for a general description of the syntax.</para>
  34
  35     <para>The main Virtual Network Device file must have the extension <filename>.netdev</filename>;
  36     other extensions are ignored. Virtual network devices are created as soon as networkd is
  37     started. If a netdev with the specified name already exists, networkd will use that as-is rather
  38     than create its own. Note that the settings of the pre-existing netdev will not be changed by
  39     networkd.</para>
  40
  41     <para>The <filename>.netdev</filename> files are read from the files located in the system
  42     network directory <filename>/usr/lib/systemd/network</filename>, the volatile runtime network
  43     directory <filename>/run/systemd/network</filename> and the local administration network
  44     directory <filename>/etc/systemd/network</filename>. All configuration files are collectively
  45     sorted and processed in lexical order, regardless of the directories in which they live.
  46     However, files with identical filenames replace each other. Files in <filename>/etc</filename>
  47     have the highest priority, files in <filename>/run</filename> take precedence over files with
  48     the same name in <filename>/usr/lib</filename>. This can be used to override a system-supplied
  49     configuration file with a local file if needed. As a special case, an empty file (file size 0)
  50     or symlink with the same name pointing to <filename>/dev/null</filename> disables the
  51     configuration file entirely (it is "masked").</para>
  52
  53     <para>Along with the netdev file <filename>foo.netdev</filename>, a "drop-in" directory
  54     <filename>foo.netdev.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  55     from this directory will be parsed after the file itself is parsed. This is useful to alter or
  56     add configuration settings, without having to modify the main configuration file. Each drop-in
  57     file must have appropriate section headers.</para>
  58
  59     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  60     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  61     <filename>/run/systemd/network</filename> directories. Drop-in files in
  62     <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
  63     take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
  64     directories take precedence over the main netdev file wherever located. (Of course, since
  65     <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is
  66     unlikely drop-ins should be used in either of those places.)</para>
  67   </refsect1>
  68
  69   <refsect1>
  70     <title>Supported netdev kinds</title>
  71
  72     <para>The following kinds of virtual network devices may be
  73     configured in <filename>.netdev</filename> files:</para>
  74
  75     <table>
  76       <title>Supported kinds of virtual network devices</title>
  77
  78       <tgroup cols='2'>
  79         <colspec colname='kind' />
  80         <colspec colname='explanation' />
  81         <thead><row>
  82           <entry>Kind</entry>
  83           <entry>Description</entry>
  84         </row></thead>
  85         <tbody>
  86           <row><entry><varname>bond</varname></entry>
  87           <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>
  88
  89           <row><entry><varname>bridge</varname></entry>
  90           <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>
  91
  92           <row><entry><varname>dummy</varname></entry>
  93           <entry>A dummy device drops all packets sent to it.</entry></row>
  94
  95           <row><entry><varname>gre</varname></entry>
  96           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
  97
  98           <row><entry><varname>gretap</varname></entry>
  99           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 100
 101           <row><entry><varname>erspan</varname></entry>
 102           <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>
 103
 104           <row><entry><varname>ip6gre</varname></entry>
 105           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 106
 107           <row><entry><varname>ip6tnl</varname></entry>
 108           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 109
 110           <row><entry><varname>ip6gretap</varname></entry>
 111           <entry>A Level 2 GRE tunnel over IPv6.</entry></row>
 112
 113           <row><entry><varname>ipip</varname></entry>
 114           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 115
 116           <row><entry><varname>ipvlan</varname></entry>
 117           <entry>An IPVLAN device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 118
 119           <row><entry><varname>ipvtap</varname></entry>
 120           <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>
 121
 122           <row><entry><varname>macvlan</varname></entry>
 123           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 124
 125           <row><entry><varname>macvtap</varname></entry>
 126           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 127
 128           <row><entry><varname>sit</varname></entry>
 129           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 130
 131           <row><entry><varname>tap</varname></entry>
 132           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 133
 134           <row><entry><varname>tun</varname></entry>
 135           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 136
 137           <row><entry><varname>veth</varname></entry>
 138           <entry>An Ethernet tunnel between a pair of network devices.</entry></row>
 139
 140           <row><entry><varname>vlan</varname></entry>
 141           <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>
 142
 143           <row><entry><varname>vti</varname></entry>
 144           <entry>An IPv4 over IPSec tunnel.</entry></row>
 145
 146           <row><entry><varname>vti6</varname></entry>
 147           <entry>An IPv6 over IPSec tunnel.</entry></row>
 148
 149           <row><entry><varname>vxlan</varname></entry>
 150           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 151
 152           <row><entry><varname>geneve</varname></entry>
 153           <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.</entry></row>
 154
 155           <row><entry><varname>l2tp</varname></entry>
 156           <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>
 157
 158           <row><entry><varname>macsec</varname></entry>
 159           <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>
 160
 161           <row><entry><varname>vrf</varname></entry>
 162           <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>
 163
 164           <row><entry><varname>vcan</varname></entry>
 165           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 166
 167           <row><entry><varname>vxcan</varname></entry>
 168           <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.
 169           </entry></row>
 170
 171           <row><entry><varname>wireguard</varname></entry>
 172           <entry>WireGuard Secure Network Tunnel.</entry></row>
 173
 174           <row><entry><varname>nlmon</varname></entry>
 175           <entry>A Netlink monitor device. Use an nlmon device when you want to monitor system Netlink messages.</entry></row>
 176
 177           <row><entry><varname>fou</varname></entry>
 178           <entry>Foo-over-UDP tunneling.</entry></row>
 179
 180           <row><entry><varname>xfrm</varname></entry>
 181           <entry>A virtual tunnel interface like vti/vti6 but with several advantages.</entry></row>
 182
 183           <row><entry><varname>ifb</varname></entry>
 184           <entry> The Intermediate Functional Block (ifb) pseudo network interface acts as a QoS concentrator for multiple different sources of traffic.</entry></row>
 185
 186         </tbody>
 187       </tgroup>
 188     </table>
 189
 190   </refsect1>
 191
 192   <refsect1>
 193     <title>[Match] Section Options</title>
 194
 195     <para>A virtual network device is only created if the
 196     [Match] section matches the current
 197     environment, or if the section is empty. The following keys are
 198     accepted:</para>
 199
 200     <variablelist class='network-directives'>
 201       <varlistentry>
 202         <term><varname>Host=</varname></term>
 203         <listitem>
 204           <para>Matches against the hostname or machine ID of the host. See
 205           <literal>ConditionHost=</literal> in
 206           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 207           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 208           If an empty string is assigned, then previously assigned value is cleared.
 209           </para>
 210         </listitem>
 211       </varlistentry>
 212       <varlistentry>
 213         <term><varname>Virtualization=</varname></term>
 214         <listitem>
 215           <para>Checks whether the system is executed in a virtualized environment and optionally test
 216           whether it is a specific implementation. See <literal>ConditionVirtualization=</literal> in
 217           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 218           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 219           If an empty string is assigned, then previously assigned value is cleared.
 220           </para>
 221         </listitem>
 222       </varlistentry>
 223       <varlistentry>
 224         <term><varname>KernelCommandLine=</varname></term>
 225         <listitem>
 226           <para>Checks whether a specific kernel command line option is set. See
 227           <literal>ConditionKernelCommandLine=</literal> in
 228           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 229           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 230           If an empty string is assigned, then previously assigned value is cleared.
 231           </para>
 232         </listitem>
 233       </varlistentry>
 234       <varlistentry>
 235         <term><varname>KernelVersion=</varname></term>
 236         <listitem>
 237           <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a
 238           certain expression. See <literal>ConditionKernelVersion=</literal> in
 239           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 240           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 241           If an empty string is assigned, then previously assigned value is cleared.
 242           </para>
 243         </listitem>
 244       </varlistentry>
 245       <varlistentry>
 246         <term><varname>Architecture=</varname></term>
 247         <listitem>
 248           <para>Checks whether the system is running on a specific architecture. See
 249           <literal>ConditionArchitecture=</literal> in
 250           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 251           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 252           If an empty string is assigned, then previously assigned value is cleared.
 253           </para>
 254         </listitem>
 255       </varlistentry>
 256     </variablelist>
 257   </refsect1>
 258
 259   <refsect1>
 260     <title>[NetDev] Section Options</title>
 261
 262     <para>The [NetDev] section accepts the
 263     following keys:</para>
 264
 265     <variablelist class='network-directives'>
 266       <varlistentry>
 267         <term><varname>Description=</varname></term>
 268         <listitem>
 269           <para>A free-form description of the netdev.</para>
 270         </listitem>
 271       </varlistentry>
 272       <varlistentry>
 273         <term><varname>Name=</varname></term>
 274         <listitem>
 275           <para>The interface name used when creating the netdev.
 276           This setting is compulsory.</para>
 277         </listitem>
 278       </varlistentry>
 279       <varlistentry>
 280         <term><varname>Kind=</varname></term>
 281         <listitem>
 282           <para>The netdev kind. This setting is compulsory. See the
 283           <literal>Supported netdev kinds</literal> section for the
 284           valid keys.</para>
 285         </listitem>
 286       </varlistentry>
 287       <varlistentry>
 288         <term><varname>MTUBytes=</varname></term>
 289         <listitem>
 290           <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M, G
 291           are supported and are understood to the base of 1024. For <literal>tun</literal> or
 292           <literal>tap</literal> devices, <varname>MTUBytes=</varname> setting is not currently supported in
 293           [NetDev] section. Please specify it in [Link] section of
 294           corresponding
 295           <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 296           files.</para>
 297         </listitem>
 298       </varlistentry>
 299       <varlistentry>
 300         <term><varname>MACAddress=</varname></term>
 301         <listitem>
 302           <para>The MAC address to use for the device. For <literal>tun</literal> or <literal>tap</literal>
 303           devices, setting <varname>MACAddress=</varname> in the [NetDev] section is not
 304           supported. Please specify it in [Link] section of the corresponding
 305           <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 306           file. If this option is not set, <literal>vlan</literal> devices inherit the MAC address of the
 307           physical interface. For other kind of netdevs, if this option is not set, then MAC address is
 308           generated based on the interface name and the
 309           <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 310           </para>
 311         </listitem>
 312       </varlistentry>
 313     </variablelist>
 314   </refsect1>
 315
 316   <refsect1>
 317     <title>[Bridge] Section Options</title>
 318
 319     <para>The [Bridge] section only applies for
 320     netdevs of kind <literal>bridge</literal>, and accepts the
 321     following keys:</para>
 322
 323     <variablelist class='network-directives'>
 324       <varlistentry>
 325         <term><varname>HelloTimeSec=</varname></term>
 326         <listitem>
 327           <para>HelloTimeSec specifies the number of seconds between two hello packets
 328           sent out by the root bridge and the designated bridges. Hello packets are
 329           used to communicate information about the topology throughout the entire
 330           bridged local area network.</para>
 331         </listitem>
 332       </varlistentry>
 333       <varlistentry>
 334         <term><varname>MaxAgeSec=</varname></term>
 335         <listitem>
 336           <para>MaxAgeSec specifies the number of seconds of maximum message age.
 337           If the last seen (received) hello packet is more than this number of
 338           seconds old, the bridge in question will start the takeover procedure
 339           in attempt to become the Root Bridge itself.</para>
 340         </listitem>
 341       </varlistentry>
 342       <varlistentry>
 343         <term><varname>ForwardDelaySec=</varname></term>
 344         <listitem>
 345           <para>ForwardDelaySec specifies the number of seconds spent in each
 346           of the Listening and Learning states before the Forwarding state is entered.</para>
 347         </listitem>
 348       </varlistentry>
 349       <varlistentry>
 350         <term><varname>AgeingTimeSec=</varname></term>
 351         <listitem>
 352           <para>This specifies the number of seconds a MAC Address will be kept in
 353           the forwarding database after having a packet received from this MAC Address.</para>
 354         </listitem>
 355       </varlistentry>
 356       <varlistentry>
 357         <term><varname>Priority=</varname></term>
 358         <listitem>
 359           <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 360           means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 361         </listitem>
 362       </varlistentry>
 363       <varlistentry>
 364         <term><varname>GroupForwardMask=</varname></term>
 365         <listitem>
 366           <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 367           local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 368           is performed between the specified bitmask and the exponentiation of 2^X, the
 369           lower nibble of the last octet of the MAC address. For example, a value of 8
 370           would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 371         </listitem>
 372       </varlistentry>
 373       <varlistentry>
 374         <term><varname>DefaultPVID=</varname></term>
 375         <listitem>
 376           <para>This specifies the default port VLAN ID of a newly attached bridge port.
 377           Set this to an integer in the range 1–4094 or <literal>none</literal> to disable the PVID.</para>
 378         </listitem>
 379       </varlistentry>
 380       <varlistentry>
 381         <term><varname>MulticastQuerier=</varname></term>
 382         <listitem>
 383           <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 384           If enabled, the kernel will send general ICMP queries from a zero source address.
 385           This feature should allow faster convergence on startup, but it causes some
 386           multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 387           When unset, the kernel's default will be used.
 388           </para>
 389         </listitem>
 390       </varlistentry>
 391       <varlistentry>
 392         <term><varname>MulticastSnooping=</varname></term>
 393         <listitem>
 394           <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
 395           If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
 396           between hosts and multicast routers. When unset, the kernel's default will be used.
 397           </para>
 398         </listitem>
 399       </varlistentry>
 400       <varlistentry>
 401         <term><varname>VLANFiltering=</varname></term>
 402         <listitem>
 403           <para>Takes a boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 404           If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's default will be used.
 405           </para>
 406         </listitem>
 407       </varlistentry>
 408       <varlistentry>
 409         <term><varname>VLANProtocol=</varname></term>
 410         <listitem>
 411           <para>Allows setting the protocol used for VLAN filtering. Takes
 412           <option>802.1q</option> or,
 413           <option>802.1ad</option>, and defaults to unset and kernel's default is used.
 414           </para>
 415         </listitem>
 416       </varlistentry>
 417       <varlistentry>
 418         <term><varname>STP=</varname></term>
 419         <listitem>
 420           <para>Takes a boolean. This enables the bridge's Spanning Tree Protocol (STP).
 421           When unset, the kernel's default will be used.
 422           </para>
 423         </listitem>
 424       </varlistentry>
 425       <varlistentry>
 426         <term><varname>MulticastIGMPVersion=</varname></term>
 427         <listitem>
 428           <para>Allows changing bridge's multicast Internet Group Management Protocol (IGMP) version.
 429           Takes an integer 2 or 3. When unset, the kernel's default will be used.
 430           </para>
 431         </listitem>
 432       </varlistentry>
 433     </variablelist>
 434   </refsect1>
 435
 436   <refsect1>
 437     <title>[VLAN] Section Options</title>
 438
 439     <para>The [VLAN] section only applies for
 440     netdevs of kind <literal>vlan</literal>, and accepts the
 441     following key:</para>
 442
 443     <variablelist class='network-directives'>
 444       <varlistentry>
 445         <term><varname>Id=</varname></term>
 446         <listitem>
 447           <para>The VLAN ID to use. An integer in the range 0–4094.
 448           This setting is compulsory.</para>
 449         </listitem>
 450       </varlistentry>
 451       <varlistentry>
 452         <term><varname>GVRP=</varname></term>
 453         <listitem>
 454           <para>Takes a boolean. The Generic VLAN Registration Protocol (GVRP) is a protocol that
 455           allows automatic learning of VLANs on a network.
 456           When unset, the kernel's default will be used.
 457           </para>
 458         </listitem>
 459       </varlistentry>
 460       <varlistentry>
 461         <term><varname>MVRP=</varname></term>
 462         <listitem>
 463           <para>Takes a boolean. Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 464           Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 465           for automatic configuration of VLAN information on switches. It was defined
 466           in the 802.1ak amendment to 802.1Q-2005. When unset, the kernel's default will be used.
 467           </para>
 468         </listitem>
 469       </varlistentry>
 470       <varlistentry>
 471         <term><varname>LooseBinding=</varname></term>
 472         <listitem>
 473           <para>Takes a boolean. The VLAN loose binding mode, in which only the operational state is passed
 474           from the parent to the associated VLANs, but the VLAN device state is not changed.
 475           When unset, the kernel's default will be used.</para>
 476         </listitem>
 477       </varlistentry>
 478       <varlistentry>
 479         <term><varname>ReorderHeader=</varname></term>
 480         <listitem>
 481           <para>Takes a boolean. When enabled, the VLAN reorder header is used and VLAN interfaces behave
 482           like physical interfaces. When unset, the kernel's default will be used.</para>
 483         </listitem>
 484       </varlistentry>
 485     </variablelist>
 486   </refsect1>
 487
 488   <refsect1>
 489     <title>[MACVLAN] Section Options</title>
 490
 491     <para>The [MACVLAN] section only applies for
 492     netdevs of kind <literal>macvlan</literal>, and accepts the
 493     following key:</para>
 494
 495     <variablelist class='network-directives'>
 496       <varlistentry>
 497         <term><varname>Mode=</varname></term>
 498         <listitem>
 499           <para>The MACVLAN mode to use. The supported options are
 500           <literal>private</literal>,
 501           <literal>vepa</literal>,
 502           <literal>bridge</literal>, and
 503           <literal>passthru</literal>.
 504           </para>
 505         </listitem>
 506       </varlistentry>
 507     </variablelist>
 508   </refsect1>
 509
 510   <refsect1>
 511     <title>[MACVTAP] Section Options</title>
 512
 513     <para>The [MACVTAP] section applies for
 514     netdevs of kind <literal>macvtap</literal> and accepts the
 515     same key as [MACVLAN].</para>
 516   </refsect1>
 517
 518   <refsect1>
 519     <title>[IPVLAN] Section Options</title>
 520
 521     <para>The [IPVLAN] section only applies for
 522     netdevs of kind <literal>ipvlan</literal>, and accepts the
 523     following key:</para>
 524
 525     <variablelist class='network-directives'>
 526       <varlistentry>
 527         <term><varname>Mode=</varname></term>
 528         <listitem>
 529           <para>The IPVLAN mode to use. The supported options are
 530           <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 531           </para>
 532         </listitem>
 533       </varlistentry>
 534       <varlistentry>
 535         <term><varname>Flags=</varname></term>
 536         <listitem>
 537           <para>The IPVLAN flags to use. The supported options are
 538           <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 539           </para>
 540         </listitem>
 541       </varlistentry>
 542     </variablelist>
 543   </refsect1>
 544
 545   <refsect1>
 546     <title>[IPVTAP] Section Options</title>
 547
 548     <para>The [IPVTAP] section only applies for
 549     netdevs of kind <literal>ipvtap</literal> and accepts the
 550     same key as [IPVLAN].</para>
 551   </refsect1>
 552
 553   <refsect1>
 554     <title>[VXLAN] Section Options</title>
 555
 556     <para>The [VXLAN] section only applies for
 557     netdevs of kind <literal>vxlan</literal>, and accepts the
 558     following keys:</para>
 559
 560     <variablelist class='network-directives'>
 561       <varlistentry>
 562         <term><varname>VNI=</varname></term>
 563         <listitem>
 564           <para>The VXLAN Network Identifier (or VXLAN Segment ID). Takes a number in the range 1-16777215.</para>
 565         </listitem>
 566       </varlistentry>
 567       <varlistentry>
 568         <term><varname>Remote=</varname></term>
 569         <listitem>
 570           <para>Configures destination IP address.</para>
 571         </listitem>
 572       </varlistentry>
 573       <varlistentry>
 574         <term><varname>Local=</varname></term>
 575         <listitem>
 576           <para>Configures local IP address.</para>
 577         </listitem>
 578       </varlistentry>
 579       <varlistentry>
 580         <term><varname>Group=</varname></term>
 581         <listitem>
 582           <para>Configures VXLAN multicast group IP address. All members of a VXLAN must use the same
 583           multicast group address.</para>
 584         </listitem>
 585       </varlistentry>
 586       <varlistentry>
 587         <term><varname>TOS=</varname></term>
 588         <listitem>
 589           <para>The Type Of Service byte value for a vxlan interface.</para>
 590         </listitem>
 591       </varlistentry>
 592       <varlistentry>
 593         <term><varname>TTL=</varname></term>
 594         <listitem>
 595           <para>A fixed Time To Live N on Virtual eXtensible Local Area Network packets.
 596           Takes <literal>inherit</literal> or a number in the range 0–255. 0 is a special
 597           value meaning inherit the inner protocol's TTL value. <literal>inherit</literal>
 598           means that it will inherit the outer protocol's TTL value.</para>
 599         </listitem>
 600       </varlistentry>
 601       <varlistentry>
 602         <term><varname>MacLearning=</varname></term>
 603         <listitem>
 604           <para>Takes a boolean. When true, enables dynamic MAC learning
 605           to discover remote MAC addresses.</para>
 606         </listitem>
 607       </varlistentry>
 608       <varlistentry>
 609         <term><varname>FDBAgeingSec=</varname></term>
 610         <listitem>
 611           <para>The lifetime of Forwarding Database entry learnt by
 612           the kernel, in seconds.</para>
 613         </listitem>
 614       </varlistentry>
 615       <varlistentry>
 616         <term><varname>MaximumFDBEntries=</varname></term>
 617         <listitem>
 618           <para>Configures maximum number of FDB entries.</para>
 619         </listitem>
 620       </varlistentry>
 621       <varlistentry>
 622         <term><varname>ReduceARPProxy=</varname></term>
 623         <listitem>
 624           <para>Takes a boolean. When true, bridge-connected VXLAN tunnel
 625           endpoint answers ARP requests from the local bridge on behalf
 626           of remote Distributed Overlay Virtual Ethernet
 627           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 628           (DVOE)</ulink> clients. Defaults to false.</para>
 629         </listitem>
 630       </varlistentry>
 631       <varlistentry>
 632         <term><varname>L2MissNotification=</varname></term>
 633         <listitem>
 634           <para>Takes a boolean. When true, enables netlink LLADDR miss
 635           notifications.</para>
 636         </listitem>
 637       </varlistentry>
 638       <varlistentry>
 639         <term><varname>L3MissNotification=</varname></term>
 640         <listitem>
 641           <para>Takes a boolean. When true, enables netlink IP address miss notifications.</para>
 642         </listitem>
 643       </varlistentry>
 644       <varlistentry>
 645         <term><varname>RouteShortCircuit=</varname></term>
 646         <listitem>
 647           <para>Takes a boolean. When true, route short circuiting is turned
 648           on.</para>
 649         </listitem>
 650       </varlistentry>
 651       <varlistentry>
 652         <term><varname>UDPChecksum=</varname></term>
 653         <listitem>
 654           <para>Takes a boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 655         </listitem>
 656       </varlistentry>
 657       <varlistentry>
 658         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 659         <listitem>
 660           <para>Takes a boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 661         </listitem>
 662       </varlistentry>
 663       <varlistentry>
 664         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 665         <listitem>
 666           <para>Takes a boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 667         </listitem>
 668       </varlistentry>
 669       <varlistentry>
 670         <term><varname>RemoteChecksumTx=</varname></term>
 671         <listitem>
 672           <para>Takes a boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 673         </listitem>
 674       </varlistentry>
 675       <varlistentry>
 676         <term><varname>RemoteChecksumRx=</varname></term>
 677         <listitem>
 678           <para>Takes a boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 679         </listitem>
 680       </varlistentry>
 681       <varlistentry>
 682         <term><varname>GroupPolicyExtension=</varname></term>
 683         <listitem>
 684           <para>Takes a boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 685           across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 686           <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 687           VXLAN Group Policy </ulink> document. Defaults to false.</para>
 688         </listitem>
 689       </varlistentry>
 690       <varlistentry>
 691         <term><varname>GenericProtocolExtension=</varname></term>
 692         <listitem>
 693           <para>Takes a boolean. When true, Generic Protocol Extension extends the existing VXLAN protocol
 694           to provide protocol typing, OAM, and versioning capabilities. For details about the VXLAN GPE
 695           Header, see the <ulink url="https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-07">
 696           Generic Protocol Extension for VXLAN </ulink> document. If destination port is not specified and
 697           Generic Protocol Extension is set then default port of 4790 is used. Defaults to false.</para>
 698         </listitem>
 699       </varlistentry>
 700       <varlistentry>
 701         <term><varname>DestinationPort=</varname></term>
 702         <listitem>
 703           <para>Configures the default destination UDP port on a per-device basis.
 704           If destination port is not specified then Linux kernel default will be used.
 705           Set destination port 4789 to get the IANA assigned value. If not set or if the
 706           destination port is assigned the empty string the default port of 4789 is used.</para>
 707         </listitem>
 708       </varlistentry>
 709       <varlistentry>
 710         <term><varname>PortRange=</varname></term>
 711         <listitem>
 712           <para>Configures VXLAN port range. VXLAN bases source
 713           UDP port based on flow to help the receiver to be able
 714           to load balance based on outer header flow. It
 715           restricts the port range to the normal UDP local
 716           ports, and allows overriding via configuration.</para>
 717         </listitem>
 718       </varlistentry>
 719       <varlistentry>
 720         <term><varname>FlowLabel=</varname></term>
 721         <listitem>
 722           <para>Specifies the flow label to use in outgoing packets.
 723           The valid range is 0-1048575.
 724           </para>
 725         </listitem>
 726       </varlistentry>
 727       <varlistentry>
 728         <term><varname>IPDoNotFragment=</varname></term>
 729         <listitem>
 730           <para>Allows setting the IPv4 Do not Fragment (DF) bit in outgoing packets, or to inherit its
 731           value from the IPv4 inner header. Takes a boolean value, or <literal>inherit</literal>. Set
 732           to <literal>inherit</literal> if the encapsulated protocol is IPv6. When unset, the kernel's
 733           default will be used.</para>
 734         </listitem>
 735       </varlistentry>
 736     </variablelist>
 737   </refsect1>
 738
 739   <refsect1>
 740     <title>[GENEVE] Section Options</title>
 741
 742     <para>The [GENEVE] section only applies for
 743     netdevs of kind <literal>geneve</literal>, and accepts the
 744     following keys:</para>
 745
 746     <variablelist class='network-directives'>
 747       <varlistentry>
 748         <term><varname>Id=</varname></term>
 749         <listitem>
 750           <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [0-16777215]. This field is mandatory.</para>
 751         </listitem>
 752       </varlistentry>
 753       <varlistentry>
 754         <term><varname>Remote=</varname></term>
 755         <listitem>
 756           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 757         </listitem>
 758       </varlistentry>
 759       <varlistentry>
 760         <term><varname>TOS=</varname></term>
 761         <listitem>
 762           <para>Specifies the TOS value to use in outgoing packets. Ranges [1-255].</para>
 763         </listitem>
 764       </varlistentry>
 765       <varlistentry>
 766         <term><varname>TTL=</varname></term>
 767         <listitem>
 768           <para>Accepts the same values as in the [VXLAN] section, except that when unset
 769           or set to 0, the kernel's default will be used, meaning that packet TTL will be set from
 770           <filename>/proc/sys/net/ipv4/ip_default_ttl</filename>.</para>
 771         </listitem>
 772       </varlistentry>
 773       <varlistentry>
 774         <term><varname>UDPChecksum=</varname></term>
 775         <listitem>
 776           <para>Takes a boolean. When true, specifies that UDP checksum is calculated for transmitted packets
 777           over IPv4.</para>
 778         </listitem>
 779       </varlistentry>
 780       <varlistentry>
 781         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 782         <listitem>
 783           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 784         </listitem>
 785       </varlistentry>
 786       <varlistentry>
 787         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 788         <listitem>
 789           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 790         </listitem>
 791       </varlistentry>
 792       <varlistentry>
 793         <term><varname>DestinationPort=</varname></term>
 794         <listitem>
 795           <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 796           port of 6081 is used.</para>
 797         </listitem>
 798       </varlistentry>
 799       <varlistentry>
 800         <term><varname>FlowLabel=</varname></term>
 801         <listitem>
 802           <para>Specifies the flow label to use in outgoing packets.</para>
 803         </listitem>
 804       </varlistentry>
 805       <varlistentry>
 806         <term><varname>IPDoNotFragment=</varname></term>
 807         <listitem>
 808           <para>Accepts the same key in [VXLAN] section.</para>
 809         </listitem>
 810       </varlistentry>
 811     </variablelist>
 812   </refsect1>
 813
 814   <refsect1>
 815     <title>[L2TP] Section Options</title>
 816
 817     <para>The [L2TP] section only applies for
 818     netdevs of kind <literal>l2tp</literal>, and accepts the
 819     following keys:</para>
 820
 821     <variablelist class='network-directives'>
 822       <varlistentry>
 823         <term><varname>TunnelId=</varname></term>
 824         <listitem>
 825           <para>Specifies the tunnel identifier. Takes an number in the range 1–4294967295. The value used
 826           must match the <literal>PeerTunnelId=</literal> value being used at the peer. This setting is
 827           compulsory.</para>
 828         </listitem>
 829       </varlistentry>
 830       <varlistentry>
 831         <term><varname>PeerTunnelId=</varname></term>
 832         <listitem>
 833           <para>Specifies the peer tunnel id. Takes a number in the range 1—4294967295. The value used must
 834           match the <literal>PeerTunnelId=</literal> value being used at the peer. This setting is
 835           compulsory.</para>
 836         </listitem>
 837       </varlistentry>
 838       <varlistentry>
 839         <term><varname>Remote=</varname></term>
 840         <listitem>
 841           <para>Specifies the IP address of the remote peer. This setting is compulsory.</para>
 842         </listitem>
 843       </varlistentry>
 844       <varlistentry>
 845         <term><varname>Local=</varname></term>
 846         <listitem>
 847           <para>Specifies the IP address of the local interface. Takes an IP address, or the special values
 848           <literal>auto</literal>, <literal>static</literal>, or <literal>dynamic</literal>. When an address
 849           is set, then the local interface must have the address. If <literal>auto</literal>, then one of the
 850           addresses on the local interface is used. Similarly, if <literal>static</literal> or
 851           <literal>dynamic</literal> is set, then one of the static or dynamic addresses on the local
 852           interface is used. Defaults to <literal>auto</literal>.</para>
 853         </listitem>
 854       </varlistentry>
 855       <varlistentry>
 856         <term><varname>EncapsulationType=</varname></term>
 857         <listitem>
 858           <para>Specifies the encapsulation type of the tunnel. Takes one of <literal>udp</literal> or
 859           <literal>ip</literal>.</para>
 860         </listitem>
 861       </varlistentry>
 862       <varlistentry>
 863         <term><varname>UDPSourcePort=</varname></term>
 864         <listitem>
 865           <para>Specifies the UDP source port to be used for the tunnel. When UDP encapsulation is selected
 866           it's mandatory. Ignored when IP encapsulation is selected.</para>
 867         </listitem>
 868       </varlistentry>
 869       <varlistentry>
 870         <term><varname>UDPDestinationPort=</varname></term>
 871         <listitem>
 872           <para>Specifies destination port. When UDP encapsulation is selected it's mandatory. Ignored when IP
 873           encapsulation is selected.</para>
 874         </listitem>
 875       </varlistentry>
 876       <varlistentry>
 877         <term><varname>UDPChecksum=</varname></term>
 878         <listitem>
 879           <para>Takes a boolean. When true, specifies that UDP checksum is calculated for transmitted packets
 880           over IPv4.</para>
 881         </listitem>
 882       </varlistentry>
 883       <varlistentry>
 884         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 885         <listitem>
 886           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 887         </listitem>
 888       </varlistentry>
 889       <varlistentry>
 890         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 891         <listitem>
 892           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 893         </listitem>
 894       </varlistentry>
 895     </variablelist>
 896   </refsect1>
 897
 898   <refsect1>
 899     <title>[L2TPSession] Section Options</title>
 900
 901     <para>The [L2TPSession] section only applies for
 902     netdevs of kind <literal>l2tp</literal>, and accepts the
 903     following keys:</para>
 904     <variablelist class='network-directives'>
 905       <varlistentry>
 906         <term><varname>Name=</varname></term>
 907         <listitem>
 908           <para>Specifies the name of the session. This setting is compulsory.</para>
 909         </listitem>
 910       </varlistentry>
 911       <varlistentry>
 912         <term><varname>SessionId=</varname></term>
 913         <listitem>
 914           <para>Specifies the session identifier. Takes an number in the range 1–4294967295. The value used
 915           must match the <literal>SessionId=</literal> value being used at the peer. This setting is
 916           compulsory.</para>
 917         </listitem>
 918       </varlistentry>
 919       <varlistentry>
 920         <term><varname>PeerSessionId=</varname></term>
 921         <listitem>
 922           <para>Specifies the peer session identifier. Takes an number in the range 1–4294967295.
 923           The value used must match the <literal>PeerSessionId=</literal> value being used at the peer.
 924           This setting is compulsory.</para>
 925         </listitem>
 926       </varlistentry>
 927       <varlistentry>
 928         <term><varname>Layer2SpecificHeader=</varname></term>
 929         <listitem>
 930           <para>Specifies layer2specific header type of the session. One of <literal>none</literal> or <literal>default</literal>. Defaults to <literal>default</literal>.</para>
 931         </listitem>
 932       </varlistentry>
 933     </variablelist>
 934   </refsect1>
 935
 936   <refsect1>
 937     <title>[MACsec] Section Options</title>
 938
 939     <para>The [MACsec] section only applies for network devices of kind
 940     <literal>macsec</literal>, and accepts the following keys:</para>
 941
 942     <variablelist class='network-directives'>
 943       <varlistentry>
 944         <term><varname>Port=</varname></term>
 945         <listitem>
 946           <para>Specifies the port to be used for the MACsec transmit channel. The port is used to make
 947           secure channel identifier (SCI). Takes a value between 1 and 65535. Defaults to unset.
 948           </para>
 949         </listitem>
 950       </varlistentry>
 951       <varlistentry>
 952         <term><varname>Encrypt=</varname></term>
 953         <listitem>
 954           <para>Takes a boolean. When true, enable encryption. Defaults to unset.</para>
 955         </listitem>
 956       </varlistentry>
 957     </variablelist>
 958   </refsect1>
 959
 960   <refsect1>
 961     <title>[MACsecReceiveChannel] Section Options</title>
 962     <para>The [MACsecReceiveChannel] section only applies for network devices of
 963     kind <literal>macsec</literal>, and accepts the following keys:</para>
 964
 965     <variablelist class='network-directives'>
 966       <varlistentry>
 967         <term><varname>Port=</varname></term>
 968         <listitem>
 969           <para>Specifies the port to be used for the MACsec receive channel. The port is used to make
 970           secure channel identifier (SCI). Takes a value between 1 and 65535. This option is
 971           compulsory, and is not set by default.</para>
 972         </listitem>
 973       </varlistentry>
 974       <varlistentry>
 975         <term><varname>MACAddress=</varname></term>
 976         <listitem>
 977           <para>Specifies the MAC address to be used for the MACsec receive channel. The MAC address
 978           used to make secure channel identifier (SCI). This setting is compulsory, and is not set by
 979           default.</para>
 980         </listitem>
 981       </varlistentry>
 982     </variablelist>
 983   </refsect1>
 984
 985   <refsect1>
 986     <title>[MACsecTransmitAssociation] Section Options</title>
 987
 988     <para>The [MACsecTransmitAssociation] section only applies for network devices
 989     of kind <literal>macsec</literal>, and accepts the following keys:</para>
 990
 991     <variablelist class='network-directives'>
 992       <varlistentry>
 993         <term><varname>PacketNumber=</varname></term>
 994         <listitem>
 995           <para>Specifies the packet number to be used for replay protection and the construction of
 996           the initialization vector (along with the secure channel identifier [SCI]). Takes a value
 997           between 1-4,294,967,295. Defaults to unset.
 998           </para>
 999         </listitem>
1000       </varlistentry>
1001       <varlistentry>
1002         <term><varname>KeyId=</varname></term>
1003         <listitem>
1004           <para>Specifies the identification for the key. Takes a number between 0-255. This option
1005           is compulsory, and is not set by default.</para>
1006         </listitem>
1007       </varlistentry>
1008       <varlistentry>
1009         <term><varname>Key=</varname></term>
1010         <listitem>
1011           <para>Specifies the encryption key used in the transmission channel. The same key must be
1012           configured on the peer’s matching receive channel. This setting is compulsory, and is not set
1013           by default. Takes a 128-bit key encoded in a hexadecimal string, for example
1014           <literal>dffafc8d7b9a43d5b9a3dfbbf6a30c16</literal>.</para>
1015         </listitem>
1016       </varlistentry>
1017       <varlistentry>
1018         <term><varname>KeyFile=</varname></term>
1019         <listitem>
1020           <para>Takes a absolute path to a file which contains a 128-bit key encoded in a hexadecimal
1021           string, which will be used in the transmission channel. When this option is specified,
1022           <varname>Key=</varname> is ignored. Note that the file must be readable by the user
1023           <literal>systemd-network</literal>, so it should be, e.g., owned by
1024           <literal>root:systemd-network</literal> with a <literal>0640</literal> file mode.</para>
1025         </listitem>
1026       </varlistentry>
1027       <varlistentry>
1028         <term><varname>Activate=</varname></term>
1029         <listitem>
1030           <para>Takes a boolean. If enabled, then the security association is activated. Defaults to
1031           unset.</para>
1032         </listitem>
1033       </varlistentry>
1034       <varlistentry>
1035         <term><varname>UseForEncoding=</varname></term>
1036         <listitem>
1037           <para>Takes a boolean. If enabled, then the security association is used for encoding. Only
1038           one [MACsecTransmitAssociation] section can enable this option. When enabled,
1039           <varname>Activate=yes</varname> is implied. Defaults to unset.</para>
1040         </listitem>
1041       </varlistentry>
1042     </variablelist>
1043   </refsect1>
1044
1045   <refsect1>
1046     <title>[MACsecReceiveAssociation] Section Options</title>
1047
1048     <para>The [MACsecReceiveAssociation] section only applies for
1049     network devices of kind <literal>macsec</literal>, and accepts the
1050     following keys:</para>
1051
1052     <variablelist class='network-directives'>
1053       <varlistentry>
1054         <term><varname>Port=</varname></term>
1055         <listitem>
1056           <para>Accepts the same key in [MACsecReceiveChannel] section.</para>
1057         </listitem>
1058       </varlistentry>
1059       <varlistentry>
1060         <term><varname>MACAddress=</varname></term>
1061         <listitem>
1062           <para>Accepts the same key in [MACsecReceiveChannel] section.</para>
1063         </listitem>
1064       </varlistentry>
1065       <varlistentry>
1066         <term><varname>PacketNumber=</varname></term>
1067         <listitem>
1068           <para>Accepts the same key in [MACsecTransmitAssociation] section.</para>
1069         </listitem>
1070       </varlistentry>
1071       <varlistentry>
1072         <term><varname>KeyId=</varname></term>
1073         <listitem>
1074           <para>Accepts the same key in [MACsecTransmitAssociation] section.</para>
1075         </listitem>
1076       </varlistentry>
1077       <varlistentry>
1078         <term><varname>Key=</varname></term>
1079         <listitem>
1080           <para>Accepts the same key in [MACsecTransmitAssociation] section.</para>
1081         </listitem>
1082       </varlistentry>
1083       <varlistentry>
1084         <term><varname>KeyFile=</varname></term>
1085         <listitem>
1086           <para>Accepts the same key in [MACsecTransmitAssociation] section.</para>
1087         </listitem>
1088       </varlistentry>
1089       <varlistentry>
1090         <term><varname>Activate=</varname></term>
1091         <listitem>
1092           <para>Accepts the same key in [MACsecTransmitAssociation] section.</para>
1093         </listitem>
1094       </varlistentry>
1095     </variablelist>
1096   </refsect1>
1097
1098   <refsect1>
1099     <title>[Tunnel] Section Options</title>
1100
1101     <para>The [Tunnel] section only applies for
1102     netdevs of kind
1103     <literal>ipip</literal>,
1104     <literal>sit</literal>,
1105     <literal>gre</literal>,
1106     <literal>gretap</literal>,
1107     <literal>ip6gre</literal>,
1108     <literal>ip6gretap</literal>,
1109     <literal>vti</literal>,
1110     <literal>vti6</literal>,
1111     <literal>ip6tnl</literal>, and
1112     <literal>erspan</literal> and accepts
1113     the following keys:</para>
1114
1115     <variablelist class='network-directives'>
1116       <varlistentry>
1117         <term><varname>Local=</varname></term>
1118         <listitem>
1119           <para>A static local address for tunneled packets. It must be an address on another interface of
1120           this host, or the special value <literal>any</literal>.</para>
1121         </listitem>
1122       </varlistentry>
1123       <varlistentry>
1124         <term><varname>Remote=</varname></term>
1125         <listitem>
1126           <para>The remote endpoint of the tunnel. Takes an IP address or the special value
1127           <literal>any</literal>.</para>
1128         </listitem>
1129       </varlistentry>
1130       <varlistentry>
1131         <term><varname>TOS=</varname></term>
1132         <listitem>
1133           <para>The Type Of Service byte value for a tunnel interface.
1134           For details about the TOS, see the
1135           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
1136           Service in the Internet Protocol Suite </ulink> document.
1137           </para>
1138         </listitem>
1139       </varlistentry>
1140       <varlistentry>
1141         <term><varname>TTL=</varname></term>
1142         <listitem>
1143           <para>A fixed Time To Live N on tunneled packets. N is a
1144           number in the range 1–255. 0 is a special value meaning that
1145           packets inherit the TTL value. The default value for IPv4
1146           tunnels is 0 (inherit). The default value for IPv6 tunnels is
1147           64.</para>
1148         </listitem>
1149       </varlistentry>
1150       <varlistentry>
1151         <term><varname>DiscoverPathMTU=</varname></term>
1152         <listitem>
1153           <para>Takes a boolean. When true, enables Path MTU Discovery on
1154           the tunnel.</para>
1155         </listitem>
1156       </varlistentry>
1157       <varlistentry>
1158         <term><varname>IPv6FlowLabel=</varname></term>
1159         <listitem>
1160           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
1161           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
1162           RFC 2460</ulink>), which is used by a node to label packets of a flow.
1163           It is only used for IPv6 tunnels.
1164           A flow label of zero is used to indicate packets that have
1165           not been labeled.
1166           It can be configured to a value in the range 0–0xFFFFF, or be
1167           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
1168         </listitem>
1169       </varlistentry>
1170       <varlistentry>
1171         <term><varname>CopyDSCP=</varname></term>
1172         <listitem>
1173           <para>Takes a boolean. When true, the Differentiated Service Code
1174           Point (DSCP) field will be copied to the inner header from
1175           outer header during the decapsulation of an IPv6 tunnel
1176           packet. DSCP is a field in an IP packet that enables different
1177           levels of service to be assigned to network traffic.
1178           Defaults to <literal>no</literal>.
1179           </para>
1180         </listitem>
1181       </varlistentry>
1182       <varlistentry>
1183         <term><varname>EncapsulationLimit=</varname></term>
1184         <listitem>
1185           <para>The Tunnel Encapsulation Limit option specifies how many additional
1186           levels of encapsulation are permitted to be prepended to the packet.
1187           For example, a Tunnel Encapsulation Limit option containing a limit
1188           value of zero means that a packet carrying that option may not enter
1189           another tunnel before exiting the current tunnel.
1190           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
1191           The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
1192         </para>
1193         </listitem>
1194       </varlistentry>
1195       <varlistentry>
1196         <term><varname>Key=</varname></term>
1197         <listitem>
1198           <para>The <varname>Key=</varname> parameter specifies the same key to use in
1199           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
1200           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
1201           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
1202           and control path) in IP XFRM (framework used to implement IPsec protocol).
1203           See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
1204           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6,
1205           GRE, GRETAP, and ERSPAN tunnels.</para>
1206         </listitem>
1207       </varlistentry>
1208       <varlistentry>
1209         <term><varname>InputKey=</varname></term>
1210         <listitem>
1211           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
1212           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1213           and ERSPAN tunnels.</para>
1214         </listitem>
1215       </varlistentry>
1216       <varlistentry>
1217         <term><varname>OutputKey=</varname></term>
1218         <listitem>
1219           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
1220           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6, GRE, GRETAP,
1221           and ERSPAN tunnels.</para>
1222         </listitem>
1223       </varlistentry>
1224       <varlistentry>
1225         <term><varname>Mode=</varname></term>
1226         <listitem>
1227           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
1228           modes
1229           <literal>ip6ip6</literal> for IPv6 over IPv6,
1230           <literal>ipip6</literal> for IPv4 over IPv6 or
1231           <literal>any</literal> for either.
1232           </para>
1233         </listitem>
1234       </varlistentry>
1235       <varlistentry>
1236         <term><varname>Independent=</varname></term>
1237         <listitem>
1238           <para>Takes a boolean. When true tunnel does not require .network file. Created as "tunnel@NONE".
1239           Defaults to <literal>false</literal>.
1240           </para>
1241         </listitem>
1242       </varlistentry>
1243       <varlistentry>
1244         <term><varname>AssignToLoopback=</varname></term>
1245         <listitem>
1246           <para>Takes a boolean. If set to <literal>yes</literal>, the loopback interface <literal>lo</literal>
1247           is used as the underlying device of the tunnel interface. Defaults to <literal>no</literal>.</para>
1248         </listitem>
1249       </varlistentry>
1250       <varlistentry>
1251         <term><varname>AllowLocalRemote=</varname></term>
1252         <listitem>
1253           <para>Takes a boolean. When true allows tunnel traffic on <varname>ip6tnl</varname> devices where the remote endpoint is a local host address.
1254           When unset, the kernel's default will be used.
1255           </para>
1256         </listitem>
1257       </varlistentry>
1258       <varlistentry>
1259         <term><varname>FooOverUDP=</varname></term>
1260         <listitem>
1261           <para>Takes a boolean. Specifies whether <varname>FooOverUDP=</varname> tunnel is to be configured.
1262           Defaults to false. This takes effects only for IPIP, SIT, GRE, and GRETAP tunnels.
1263           For more detail information see
1264           <ulink url="https://lwn.net/Articles/614348">Foo over UDP</ulink></para>
1265         </listitem>
1266       </varlistentry>
1267       <varlistentry>
1268         <term><varname>FOUDestinationPort=</varname></term>
1269         <listitem>
1270           <para>This setting specifies the UDP destination port for encapsulation.
1271           This field is mandatory when <varname>FooOverUDP=yes</varname>, and is not set by default.</para>
1272         </listitem>
1273       </varlistentry>
1274       <varlistentry>
1275         <term><varname>FOUSourcePort=</varname></term>
1276         <listitem>
1277           <para>This setting specifies the UDP source port for encapsulation. Defaults to <constant>0</constant>
1278           — that is, the source port for packets is left to the network stack to decide.</para>
1279         </listitem>
1280       </varlistentry>
1281       <varlistentry>
1282         <term><varname>Encapsulation=</varname></term>
1283         <listitem>
1284           <para>Accepts the same key as in the [FooOverUDP] section.</para>
1285         </listitem>
1286       </varlistentry>
1287       <varlistentry>
1288         <term><varname>IPv6RapidDeploymentPrefix=</varname></term>
1289         <listitem>
1290           <para>Reconfigure the tunnel for <ulink url="https://tools.ietf.org/html/rfc5569">IPv6 Rapid
1291           Deployment</ulink>, also known as 6rd. The value is an ISP-specific IPv6 prefix with a non-zero length. Only
1292           applicable to SIT tunnels.</para>
1293         </listitem>
1294       </varlistentry>
1295       <varlistentry>
1296         <term><varname>ISATAP=</varname></term>
1297         <listitem>
1298           <para>Takes a boolean. If set, configures the tunnel as Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) tunnel.
1299           Only applicable to SIT tunnels. When unset, the kernel's default will be used.</para>
1300         </listitem>
1301       </varlistentry>
1302       <varlistentry>
1303         <term><varname>SerializeTunneledPackets=</varname></term>
1304         <listitem>
1305           <para>Takes a boolean. If set to yes, then packets are serialized. Only applies for GRE,
1306           GRETAP, and ERSPAN tunnels. When unset, the kernel's default will be used.
1307           </para>
1308         </listitem>
1309       </varlistentry>
1310       <varlistentry>
1311         <term><varname>ERSPANIndex=</varname></term>
1312         <listitem>
1313           <para>Specifies the ERSPAN index field for the interface, an integer in the range 1-1048575 associated with
1314           the ERSPAN traffic's source port and direction. This field is mandatory.
1315           </para>
1316         </listitem>
1317       </varlistentry>
1318     </variablelist>
1319   </refsect1>
1320
1321   <refsect1>
1322     <title>[FooOverUDP] Section Options</title>
1323
1324     <para>The [FooOverUDP] section only applies for
1325     netdevs of kind <literal>fou</literal> and accepts the
1326     following keys:</para>
1327
1328     <variablelist class='network-directives'>
1329       <varlistentry>
1330         <term><varname>Encapsulation=</varname></term>
1331         <listitem>
1332           <para>Specifies the encapsulation mechanism used to store networking packets of various protocols
1333           inside the UDP packets. Supports the following values:
1334
1335           <literal>FooOverUDP</literal> provides the simplest no frills model of UDP encapsulation, it simply
1336           encapsulates packets directly in the UDP payload. <literal>GenericUDPEncapsulation</literal> is a
1337           generic and extensible encapsulation, it allows encapsulation of packets for any IP protocol and
1338           optional data as part of the encapsulation. For more detailed information see <ulink
1339           url="https://lwn.net/Articles/615044">Generic UDP Encapsulation</ulink>. Defaults to
1340           <literal>FooOverUDP</literal>.
1341           </para>
1342         </listitem>
1343       </varlistentry>
1344       <varlistentry>
1345         <term><varname>Port=</varname></term>
1346         <listitem>
1347           <para>Specifies the port number, where the IP encapsulation packets will arrive. Please take note
1348           that the packets will arrive with the encapsulation will be removed. Then they will be manually fed
1349           back into the network stack, and sent ahead for delivery to the real destination. This option is
1350           mandatory.</para>
1351         </listitem>
1352       </varlistentry>
1353       <varlistentry>
1354         <term><varname>PeerPort=</varname></term>
1355         <listitem>
1356           <para>Specifies the peer port number. Defaults to unset. Note that when peer port is set
1357           <literal>Peer=</literal> address is mandatory.</para>
1358         </listitem>
1359       </varlistentry>
1360       <varlistentry>
1361         <term><varname>Protocol=</varname></term>
1362         <listitem>
1363           <para>The <varname>Protocol=</varname> specifies the protocol number of the packets arriving
1364           at the UDP port. When <varname>Encapsulation=FooOverUDP</varname>, this field is mandatory
1365           and is not set by default. Takes an IP protocol name such as <literal>gre</literal> or
1366           <literal>ipip</literal>, or an integer within the range 1-255. When
1367           <varname>Encapsulation=GenericUDPEncapsulation</varname>, this must not be specified.</para>
1368         </listitem>
1369       </varlistentry>
1370       <varlistentry>
1371         <term><varname>Peer=</varname></term>
1372         <listitem>
1373           <para>Configures peer IP address. Note that when peer address is set <literal>PeerPort=</literal>
1374           is mandatory.</para>
1375         </listitem>
1376       </varlistentry>
1377       <varlistentry>
1378         <term><varname>Local=</varname></term>
1379         <listitem>
1380           <para>Configures local IP address.</para>
1381         </listitem>
1382       </varlistentry>
1383     </variablelist>
1384   </refsect1>
1385
1386   <refsect1>
1387     <title>[Peer] Section Options</title>
1388
1389     <para>The [Peer] section only applies for
1390     netdevs of kind <literal>veth</literal> and accepts the
1391     following keys:</para>
1392
1393     <variablelist class='network-directives'>
1394       <varlistentry>
1395         <term><varname>Name=</varname></term>
1396         <listitem>
1397           <para>The interface name used when creating the netdev.
1398           This setting is compulsory.</para>
1399         </listitem>
1400       </varlistentry>
1401       <varlistentry>
1402         <term><varname>MACAddress=</varname></term>
1403         <listitem>
1404           <para>The peer MACAddress, if not set, it is generated in
1405           the same way as the MAC address of the main
1406           interface.</para>
1407         </listitem>
1408       </varlistentry>
1409     </variablelist>
1410   </refsect1>
1411
1412   <refsect1>
1413     <title>[VXCAN] Section Options</title>
1414
1415     <para>The [VXCAN] section only applies for
1416     netdevs of kind <literal>vxcan</literal> and accepts the
1417     following key:</para>
1418
1419     <variablelist class='network-directives'>
1420       <varlistentry>
1421         <term><varname>Peer=</varname></term>
1422         <listitem>
1423           <para>The peer interface name used when creating the netdev.
1424           This setting is compulsory.</para>
1425         </listitem>
1426       </varlistentry>
1427     </variablelist>
1428   </refsect1>
1429
1430   <refsect1>
1431     <title>[Tun] Section Options</title>
1432
1433     <para>The [Tun] section only applies for
1434     netdevs of kind <literal>tun</literal>, and accepts the following
1435     keys:</para>
1436
1437     <variablelist class='network-directives'>
1438       <varlistentry>
1439         <term><varname>MultiQueue=</varname></term>
1440         <listitem><para>Takes a boolean. Configures whether
1441         to use multiple file descriptors (queues) to parallelize
1442         packets sending and receiving. Defaults to
1443         <literal>no</literal>.</para>
1444         </listitem>
1445       </varlistentry>
1446       <varlistentry>
1447         <term><varname>PacketInfo=</varname></term>
1448         <listitem><para>Takes a boolean. Configures whether
1449         packets should be prepended with four extra bytes (two flag
1450         bytes and two protocol bytes). If disabled, it indicates that
1451         the packets will be pure IP packets. Defaults to
1452         <literal>no</literal>.</para>
1453         </listitem>
1454       </varlistentry>
1455       <varlistentry>
1456         <term><varname>VNetHeader=</varname></term>
1457         <listitem><para>Takes a boolean. Configures
1458         IFF_VNET_HDR flag for a tun or tap device. It allows sending
1459         and receiving larger Generic Segmentation Offload (GSO)
1460         packets. This may increase throughput significantly.
1461         Defaults to
1462         <literal>no</literal>.</para>
1463         </listitem>
1464       </varlistentry>
1465       <varlistentry>
1466         <term><varname>User=</varname></term>
1467         <listitem><para>User to grant access to the
1468         <filename>/dev/net/tun</filename> device.</para>
1469         </listitem>
1470       </varlistentry>
1471       <varlistentry>
1472         <term><varname>Group=</varname></term>
1473         <listitem><para>Group to grant access to the
1474         <filename>/dev/net/tun</filename> device.</para>
1475         </listitem>
1476       </varlistentry>
1477     </variablelist>
1478   </refsect1>
1479
1480   <refsect1>
1481     <title>[Tap] Section Options</title>
1482
1483     <para>The [Tap] section only applies for
1484     netdevs of kind <literal>tap</literal>, and accepts the same keys
1485     as the [Tun] section.</para>
1486   </refsect1>
1487
1488   <refsect1>
1489     <title>[WireGuard] Section Options</title>
1490
1491     <para>The [WireGuard] section accepts the following
1492     keys:</para>
1493
1494     <variablelist class='network-directives'>
1495       <varlistentry>
1496         <term><varname>PrivateKey=</varname></term>
1497         <listitem>
1498           <para>The Base64 encoded private key for the interface. It can be
1499           generated using the <command>wg genkey</command> command
1500           (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1501           This option or <varname>PrivateKeyFile=</varname> is mandatory to use WireGuard.
1502           Note that because this information is secret, you may want to set
1503           the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1504           with a <literal>0640</literal> file mode.</para>
1505         </listitem>
1506       </varlistentry>
1507       <varlistentry>
1508         <term><varname>PrivateKeyFile=</varname></term>
1509         <listitem>
1510           <para>Takes an absolute path to a file which contains the Base64 encoded private key for the interface.
1511           When this option is specified, then <varname>PrivateKey=</varname> is ignored.
1512           Note that the file must be readable by the user <literal>systemd-network</literal>, so it
1513           should be, e.g., owned by <literal>root:systemd-network</literal> with a
1514           <literal>0640</literal> file mode.</para>
1515         </listitem>
1516       </varlistentry>
1517       <varlistentry>
1518         <term><varname>ListenPort=</varname></term>
1519         <listitem>
1520           <para>Sets UDP port for listening. Takes either value between 1 and 65535
1521           or <literal>auto</literal>. If <literal>auto</literal> is specified,
1522           the port is automatically generated based on interface name.
1523           Defaults to <literal>auto</literal>.</para>
1524         </listitem>
1525       </varlistentry>
1526       <varlistentry>
1527         <term><varname>FirewallMark=</varname></term>
1528         <listitem>
1529           <para>Sets a firewall mark on outgoing WireGuard packets from this interface. Takes a number between 1 and 4294967295.</para>
1530         </listitem>
1531       </varlistentry>
1532     </variablelist>
1533   </refsect1>
1534
1535   <refsect1>
1536     <title>[WireGuardPeer] Section Options</title>
1537
1538     <para>The [WireGuardPeer] section accepts the following
1539     keys:</para>
1540
1541     <variablelist class='network-directives'>
1542       <varlistentry>
1543         <term><varname>PublicKey=</varname></term>
1544         <listitem>
1545           <para>Sets a Base64 encoded public key calculated by <command>wg pubkey</command>
1546           (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1547           from a private key, and usually transmitted out of band to the
1548           author of the configuration file. This option is mandatory for this
1549           section.</para>
1550         </listitem>
1551       </varlistentry>
1552       <varlistentry>
1553         <term><varname>PresharedKey=</varname></term>
1554         <listitem>
1555           <para>Optional preshared key for the interface. It can be generated
1556           by the <command>wg genpsk</command> command. This option adds an
1557           additional layer of symmetric-key cryptography to be mixed into the
1558           already existing public-key cryptography, for post-quantum
1559           resistance.
1560           Note that because this information is secret, you may want to set
1561           the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1562           with a <literal>0640</literal> file mode.</para>
1563         </listitem>
1564       </varlistentry>
1565       <varlistentry>
1566         <term><varname>PresharedKeyFile=</varname></term>
1567         <listitem>
1568           <para>Takes an absolute path to a file which contains the Base64 encoded preshared key for the
1569           peer. When this option is specified, then <varname>PresharedKey=</varname> is ignored.
1570           Note that the file must be readable by the user <literal>systemd-network</literal>, so it
1571           should be, e.g., owned by <literal>root:systemd-network</literal> with a
1572           <literal>0640</literal> file mode.</para>
1573         </listitem>
1574       </varlistentry>
1575       <varlistentry>
1576         <term><varname>AllowedIPs=</varname></term>
1577         <listitem>
1578           <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks
1579           from which this peer is allowed to send incoming traffic and to
1580           which outgoing traffic for this peer is directed. The catch-all
1581           0.0.0.0/0 may be specified for matching all IPv4 addresses, and
1582           ::/0 may be specified for matching all IPv6 addresses. </para>
1583         </listitem>
1584       </varlistentry>
1585       <varlistentry>
1586         <term><varname>Endpoint=</varname></term>
1587         <listitem>
1588           <para>Sets an endpoint IP address or hostname, followed by a colon, and then
1589           a port number. This endpoint will be updated automatically once to
1590           the most recent source IP address and port of correctly
1591           authenticated packets from the peer at configuration time.</para>
1592         </listitem>
1593       </varlistentry>
1594       <varlistentry>
1595         <term><varname>PersistentKeepalive=</varname></term>
1596         <listitem>
1597           <para>Sets a seconds interval, between 1 and 65535 inclusive, of how often
1598           to send an authenticated empty packet to the peer for the purpose
1599           of keeping a stateful firewall or NAT mapping valid persistently.
1600           For example, if the interface very rarely sends traffic, but it
1601           might at anytime receive traffic from a peer, and it is behind NAT,
1602           the interface might benefit from having a persistent keepalive
1603           interval of 25 seconds. If set to 0 or "off", this option is
1604           disabled. By default or when unspecified, this option is off.
1605           Most users will not need this.</para>
1606         </listitem>
1607       </varlistentry>
1608     </variablelist>
1609   </refsect1>
1610
1611   <refsect1>
1612     <title>[Bond] Section Options</title>
1613
1614     <para>The [Bond] section accepts the following
1615     key:</para>
1616
1617     <variablelist class='network-directives'>
1618       <varlistentry>
1619         <term><varname>Mode=</varname></term>
1620         <listitem>
1621           <para>Specifies one of the bonding policies. The default is
1622           <literal>balance-rr</literal> (round robin). Possible values are
1623           <literal>balance-rr</literal>,
1624           <literal>active-backup</literal>,
1625           <literal>balance-xor</literal>,
1626           <literal>broadcast</literal>,
1627           <literal>802.3ad</literal>,
1628           <literal>balance-tlb</literal>, and
1629           <literal>balance-alb</literal>.
1630           </para>
1631         </listitem>
1632       </varlistentry>
1633
1634       <varlistentry>
1635         <term><varname>TransmitHashPolicy=</varname></term>
1636         <listitem>
1637           <para>Selects the transmit hash policy to use for slave
1638           selection in balance-xor, 802.3ad, and tlb modes. Possible
1639           values are
1640           <literal>layer2</literal>,
1641           <literal>layer3+4</literal>,
1642           <literal>layer2+3</literal>,
1643           <literal>encap2+3</literal>, and
1644           <literal>encap3+4</literal>.
1645           </para>
1646         </listitem>
1647       </varlistentry>
1648
1649       <varlistentry>
1650         <term><varname>LACPTransmitRate=</varname></term>
1651         <listitem>
1652           <para>Specifies the rate with which link partner transmits
1653           Link Aggregation Control Protocol Data Unit packets in
1654           802.3ad mode. Possible values are <literal>slow</literal>,
1655           which requests partner to transmit LACPDUs every 30 seconds,
1656           and <literal>fast</literal>, which requests partner to
1657           transmit LACPDUs every second. The default value is
1658           <literal>slow</literal>.</para>
1659         </listitem>
1660       </varlistentry>
1661
1662       <varlistentry>
1663         <term><varname>MIIMonitorSec=</varname></term>
1664         <listitem>
1665           <para>Specifies the frequency that Media Independent
1666           Interface link monitoring will occur. A value of zero
1667           disables MII link monitoring. This value is rounded down to
1668           the nearest millisecond. The default value is 0.</para>
1669         </listitem>
1670       </varlistentry>
1671
1672       <varlistentry>
1673         <term><varname>UpDelaySec=</varname></term>
1674         <listitem>
1675           <para>Specifies the delay before a link is enabled after a
1676           link up status has been detected. This value is rounded down
1677           to a multiple of MIIMonitorSec. The default value is
1678           0.</para>
1679         </listitem>
1680       </varlistentry>
1681
1682       <varlistentry>
1683         <term><varname>DownDelaySec=</varname></term>
1684         <listitem>
1685           <para>Specifies the delay before a link is disabled after a
1686           link down status has been detected. This value is rounded
1687           down to a multiple of MIIMonitorSec. The default value is
1688           0.</para>
1689         </listitem>
1690       </varlistentry>
1691
1692       <varlistentry>
1693         <term><varname>LearnPacketIntervalSec=</varname></term>
1694         <listitem>
1695           <para>Specifies the number of seconds between instances where the bonding
1696           driver sends learning packets to each slave peer switch.
1697           The valid range is 1–0x7fffffff; the default value is 1. This option
1698           has an effect only for the balance-tlb and balance-alb modes.</para>
1699         </listitem>
1700       </varlistentry>
1701
1702       <varlistentry>
1703         <term><varname>AdSelect=</varname></term>
1704         <listitem>
1705           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
1706           <literal>stable</literal>,
1707           <literal>bandwidth</literal> and
1708           <literal>count</literal>.
1709           </para>
1710         </listitem>
1711       </varlistentry>
1712
1713       <varlistentry>
1714         <term><varname>AdActorSystemPriority=</varname></term>
1715         <listitem>
1716           <para>Specifies the 802.3ad actor system priority. Takes a number in the range 1—65535.</para>
1717         </listitem>
1718       </varlistentry>
1719
1720       <varlistentry>
1721         <term><varname>AdUserPortKey=</varname></term>
1722         <listitem>
1723           <para>Specifies the 802.3ad user defined portion of the port key. Takes a number in the range
1724           0–1023.</para>
1725         </listitem>
1726       </varlistentry>
1727
1728       <varlistentry>
1729         <term><varname>AdActorSystem=</varname></term>
1730         <listitem>
1731           <para>Specifies the 802.3ad system mac address. This can not be either NULL or Multicast.</para>
1732         </listitem>
1733       </varlistentry>
1734
1735       <varlistentry>
1736         <term><varname>FailOverMACPolicy=</varname></term>
1737         <listitem>
1738           <para>Specifies whether the active-backup mode should set all slaves to
1739           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1740           bond's MAC address in accordance with the selected policy. The default policy is none.
1741           Possible values are
1742           <literal>none</literal>,
1743           <literal>active</literal> and
1744           <literal>follow</literal>.
1745           </para>
1746         </listitem>
1747       </varlistentry>
1748
1749       <varlistentry>
1750         <term><varname>ARPValidate=</varname></term>
1751         <listitem>
1752           <para>Specifies whether or not ARP probes and replies should be
1753           validated in any mode that supports ARP monitoring, or whether
1754           non-ARP traffic should be filtered (disregarded) for link
1755           monitoring purposes. Possible values are
1756           <literal>none</literal>,
1757           <literal>active</literal>,
1758           <literal>backup</literal> and
1759           <literal>all</literal>.
1760           </para>
1761         </listitem>
1762       </varlistentry>
1763
1764       <varlistentry>
1765         <term><varname>ARPIntervalSec=</varname></term>
1766         <listitem>
1767           <para>Specifies the ARP link monitoring frequency. A value of 0 disables ARP monitoring. The
1768           default value is 0, and the default unit seconds.
1769           </para>
1770         </listitem>
1771       </varlistentry>
1772
1773       <varlistentry>
1774         <term><varname>ARPIPTargets=</varname></term>
1775         <listitem>
1776           <para>Specifies the IP addresses to use as ARP monitoring peers when
1777           ARPIntervalSec is greater than 0. These are the targets of the ARP request
1778           sent to determine the health of the link to the targets.
1779           Specify these values in IPv4 dotted decimal format. At least one IP
1780           address must be given for ARP monitoring to function. The
1781           maximum number of targets that can be specified is 16. The
1782           default value is no IP addresses.
1783           </para>
1784         </listitem>
1785       </varlistentry>
1786
1787       <varlistentry>
1788         <term><varname>ARPAllTargets=</varname></term>
1789         <listitem>
1790           <para>Specifies the quantity of ARPIPTargets that must be reachable
1791           in order for the ARP monitor to consider a slave as being up.
1792           This option affects only active-backup mode for slaves with
1793           ARPValidate enabled. Possible values are
1794           <literal>any</literal> and
1795           <literal>all</literal>.
1796           </para>
1797         </listitem>
1798       </varlistentry>
1799
1800       <varlistentry>
1801         <term><varname>PrimaryReselectPolicy=</varname></term>
1802         <listitem>
1803           <para>Specifies the reselection policy for the primary slave.  This
1804           affects how the primary slave is chosen to become the active slave
1805           when failure of the active slave or recovery of the primary slave
1806           occurs. This option is designed to prevent flip-flopping between
1807           the primary slave and other slaves.  Possible values are
1808           <literal>always</literal>,
1809           <literal>better</literal> and
1810           <literal>failure</literal>.
1811           </para>
1812         </listitem>
1813       </varlistentry>
1814
1815       <varlistentry>
1816         <term><varname>ResendIGMP=</varname></term>
1817         <listitem>
1818           <para>Specifies the number of IGMP membership reports to be issued after
1819           a failover event. One membership report is issued immediately after
1820           the failover, subsequent packets are sent in each 200ms interval.
1821           The valid range is 0–255. Defaults to 1. A value of 0
1822           prevents the IGMP membership report from being issued in response
1823           to the failover event.
1824           </para>
1825         </listitem>
1826       </varlistentry>
1827
1828       <varlistentry>
1829         <term><varname>PacketsPerSlave=</varname></term>
1830         <listitem>
1831           <para>Specify the number of packets to transmit through a slave before
1832           moving to the next one. When set to 0, then a slave is chosen at
1833           random. The valid range is 0–65535. Defaults to 1. This option
1834           only has effect when in balance-rr mode.
1835           </para>
1836         </listitem>
1837       </varlistentry>
1838
1839       <varlistentry>
1840         <term><varname>GratuitousARP=</varname></term>
1841         <listitem>
1842           <para>Specify the number of peer notifications (gratuitous ARPs and
1843           unsolicited IPv6 Neighbor Advertisements) to be issued after a
1844           failover event.  As soon as the link is up on the new slave,
1845           a peer notification is sent on the  bonding device and each
1846           VLAN sub-device.  This is repeated at each link monitor interval
1847           (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1848           greater than 1. The valid range is 0–255. The default value is 1.
1849           These options affect only the active-backup mode.
1850           </para>
1851         </listitem>
1852       </varlistentry>
1853
1854       <varlistentry>
1855         <term><varname>AllSlavesActive=</varname></term>
1856         <listitem>
1857           <para>Takes a boolean. Specifies that duplicate frames (received on inactive ports)
1858           should be dropped when false, or delivered when true. Normally, bonding will drop
1859           duplicate frames (received on inactive ports), which is desirable for
1860           most users. But there are some times it is nice to allow duplicate
1861           frames to be delivered. The default value is false (drop duplicate frames
1862           received on inactive ports).
1863           </para>
1864         </listitem>
1865       </varlistentry>
1866
1867       <varlistentry>
1868         <term><varname>DynamicTransmitLoadBalancing=</varname></term>
1869         <listitem>
1870           <para>Takes a boolean. Specifies if dynamic shuffling of flows is enabled. Applies only
1871           for balance-tlb mode. Defaults to unset.
1872           </para>
1873         </listitem>
1874       </varlistentry>
1875
1876       <varlistentry>
1877         <term><varname>MinLinks=</varname></term>
1878         <listitem>
1879           <para>Specifies the minimum number of links that must be active before
1880           asserting carrier. The default value is 0.
1881           </para>
1882         </listitem>
1883       </varlistentry>
1884     </variablelist>
1885
1886     <para>For more detail information see
1887     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1888     Linux Ethernet Bonding Driver HOWTO</ulink></para>
1889   </refsect1>
1890
1891   <refsect1>
1892     <title>[Xfrm] Section Options</title>
1893
1894     <para>The [Xfrm] section accepts the following
1895     keys:</para>
1896
1897     <variablelist class='network-directives'>
1898       <varlistentry>
1899         <term><varname>InterfaceId=</varname></term>
1900         <listitem>
1901           <para>Sets the ID/key of the xfrm interface which needs to be associated with a SA/policy.
1902           Can be decimal or hexadecimal, valid range is 0-0xffffffff, defaults to 0.</para>
1903         </listitem>
1904       </varlistentry>
1905       <varlistentry>
1906         <term><varname>Independent=</varname></term>
1907         <listitem>
1908           <para>Takes a boolean. If set to <literal>no</literal>, the xfrm interface should have an
1909           underlying device which can be used for hardware offloading. Defaults to <literal>no</literal>.
1910           See <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1911           for how to configure the underlying device.</para>
1912         </listitem>
1913       </varlistentry>
1914     </variablelist>
1915
1916     <para>For more detail information see
1917       <ulink url="https://lwn.net/Articles/757391">Virtual XFRM Interfaces</ulink>.</para>
1918   </refsect1>
1919
1920   <refsect1>
1921     <title>[VRF] Section Options</title>
1922     <para>The [VRF] section only applies for
1923     netdevs of kind <literal>vrf</literal> and accepts the
1924     following key:</para>
1925
1926     <variablelist class='network-directives'>
1927       <varlistentry>
1928         <term><varname>Table=</varname></term>
1929         <listitem>
1930           <para>The numeric routing table identifier. This setting is compulsory.</para>
1931         </listitem>
1932       </varlistentry>
1933     </variablelist>
1934   </refsect1>
1935
1936   <refsect1>
1937     <title>Examples</title>
1938     <example>
1939       <title>/etc/systemd/network/25-bridge.netdev</title>
1940
1941       <programlisting>[NetDev]
1942 Name=bridge0
1943 Kind=bridge</programlisting>
1944     </example>
1945
1946     <example>
1947       <title>/etc/systemd/network/25-vlan1.netdev</title>
1948
1949       <programlisting>[Match]
1950 Virtualization=no
1951
1952 [NetDev]
1953 Name=vlan1
1954 Kind=vlan
1955
1956 [VLAN]
1957 Id=1</programlisting>
1958     </example>
1959     <example>
1960       <title>/etc/systemd/network/25-ipip.netdev</title>
1961       <programlisting>[NetDev]
1962 Name=ipip-tun
1963 Kind=ipip
1964 MTUBytes=1480
1965
1966 [Tunnel]
1967 Local=192.168.223.238
1968 Remote=192.169.224.239
1969 TTL=64</programlisting>
1970     </example>
1971     <example>
1972       <title>/etc/systemd/network/1-fou-tunnel.netdev</title>
1973       <programlisting>[NetDev]
1974 Name=fou-tun
1975 Kind=fou
1976
1977 [FooOverUDP]
1978 Port=5555
1979 Protocol=4
1980       </programlisting>
1981     </example>
1982     <example>
1983       <title>/etc/systemd/network/25-fou-ipip.netdev</title>
1984       <programlisting>[NetDev]
1985 Name=ipip-tun
1986 Kind=ipip
1987
1988 [Tunnel]
1989 Independent=yes
1990 Local=10.65.208.212
1991 Remote=10.65.208.211
1992 FooOverUDP=yes
1993 FOUDestinationPort=5555
1994       </programlisting>
1995     </example>
1996     <example>
1997       <title>/etc/systemd/network/25-tap.netdev</title>
1998       <programlisting>[NetDev]
1999 Name=tap-test
2000 Kind=tap
2001
2002 [Tap]
2003 MultiQueue=yes
2004 PacketInfo=yes</programlisting> </example>
2005
2006     <example>
2007       <title>/etc/systemd/network/25-sit.netdev</title>
2008       <programlisting>[NetDev]
2009 Name=sit-tun
2010 Kind=sit
2011 MTUBytes=1480
2012
2013 [Tunnel]
2014 Local=10.65.223.238
2015 Remote=10.65.223.239</programlisting>
2016     </example>
2017
2018     <example>
2019       <title>/etc/systemd/network/25-6rd.netdev</title>
2020       <programlisting>[NetDev]
2021 Name=6rd-tun
2022 Kind=sit
2023 MTUBytes=1480
2024
2025 [Tunnel]
2026 Local=10.65.223.238
2027 IPv6RapidDeploymentPrefix=2602::/24</programlisting>
2028     </example>
2029
2030     <example>
2031       <title>/etc/systemd/network/25-gre.netdev</title>
2032       <programlisting>[NetDev]
2033 Name=gre-tun
2034 Kind=gre
2035 MTUBytes=1480
2036
2037 [Tunnel]
2038 Local=10.65.223.238
2039 Remote=10.65.223.239</programlisting>
2040     </example>
2041
2042     <example>
2043       <title>/etc/systemd/network/25-ip6gre.netdev</title>
2044       <programlisting>[NetDev]
2045 Name=ip6gre-tun
2046 Kind=ip6gre
2047
2048 [Tunnel]
2049 Key=123</programlisting>
2050     </example>
2051
2052     <example>
2053       <title>/etc/systemd/network/25-vti.netdev</title>
2054
2055       <programlisting>[NetDev]
2056 Name=vti-tun
2057 Kind=vti
2058 MTUBytes=1480
2059
2060 [Tunnel]
2061 Local=10.65.223.238
2062 Remote=10.65.223.239</programlisting>
2063     </example>
2064
2065     <example>
2066       <title>/etc/systemd/network/25-veth.netdev</title>
2067       <programlisting>[NetDev]
2068 Name=veth-test
2069 Kind=veth
2070
2071 [Peer]
2072 Name=veth-peer</programlisting>
2073     </example>
2074
2075     <example>
2076       <title>/etc/systemd/network/25-bond.netdev</title>
2077       <programlisting>[NetDev]
2078 Name=bond1
2079 Kind=bond
2080
2081 [Bond]
2082 Mode=802.3ad
2083 TransmitHashPolicy=layer3+4
2084 MIIMonitorSec=1s
2085 LACPTransmitRate=fast
2086 </programlisting>
2087     </example>
2088
2089     <example>
2090       <title>/etc/systemd/network/25-dummy.netdev</title>
2091       <programlisting>[NetDev]
2092 Name=dummy-test
2093 Kind=dummy
2094 MACAddress=12:34:56:78:9a:bc</programlisting>
2095     </example>
2096     <example>
2097       <title>/etc/systemd/network/25-vrf.netdev</title>
2098       <para>Create a VRF interface with table 42.</para>
2099       <programlisting>[NetDev]
2100 Name=vrf-test
2101 Kind=vrf
2102
2103 [VRF]
2104 Table=42</programlisting>
2105     </example>
2106
2107     <example>
2108       <title>/etc/systemd/network/25-macvtap.netdev</title>
2109       <para>Create a MacVTap device.</para>
2110       <programlisting>[NetDev]
2111 Name=macvtap-test
2112 Kind=macvtap
2113       </programlisting>
2114     </example>
2115     <example>
2116       <title>/etc/systemd/network/25-wireguard.netdev</title>
2117       <programlisting>[NetDev]
2118 Name=wg0
2119 Kind=wireguard
2120
2121 [WireGuard]
2122 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
2123 ListenPort=51820
2124
2125 [WireGuardPeer]
2126 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
2127 AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
2128 Endpoint=wireguard.example.com:51820</programlisting>
2129     </example>
2130
2131     <example>
2132       <title>/etc/systemd/network/27-xfrm.netdev</title>
2133       <programlisting>[NetDev]
2134 Name=xfrm0
2135 Kind=xfrm
2136
2137 [Xfrm]
2138 Independent=yes</programlisting>
2139     </example>
2140   </refsect1>
2141
2142   <refsect1>
2143     <title>See Also</title>
2144     <para>
2145       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
2146       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
2147       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
2148       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
2149     </para>
2150   </refsect1>
2151
2152 </refentry>