man/systemd.netdev.xml

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