man/systemd.netdev.xml

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  23
  24 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>
  25
  26   <refentryinfo>
  27     <title>systemd.network</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>Developer</contrib>
  33         <firstname>Tom</firstname>
  34         <surname>Gundersen</surname>
  35         <email>teg@jklm.no</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>systemd.netdev</refentrytitle>
  42     <manvolnum>5</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>systemd.netdev</refname>
  47     <refpurpose>Virtual Network Device configuration</refpurpose>
  48   </refnamediv>
  49
  50   <refsynopsisdiv>
  51     <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  52   </refsynopsisdiv>
  53
  54   <refsect1>
  55     <title>Description</title>
  56
  57     <para>Network setup is performed by
  58     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  59     </para>
  60
  61     <para>Virtual Network Device files must have the extension
  62     <filename>.netdev</filename>; other extensions are ignored.
  63     Virtual network devices are created as soon as networkd is
  64     started. If a netdev with the specified name already exists,
  65     networkd will use that as-is rather than create its own. Note that
  66     the settings of the pre-existing netdev will not be changed by
  67     networkd.</para>
  68
  69     <para>The <filename>.netdev</filename> files are read from the
  70     files located in the system network directory
  71     <filename>/usr/lib/systemd/network</filename>, the volatile
  72     runtime network directory
  73     <filename>/run/systemd/network</filename> and the local
  74     administration network directory
  75     <filename>/etc/systemd/network</filename>. All configuration files
  76     are collectively sorted and processed in lexical order, regardless
  77     of the directories in which they live. However, files with
  78     identical filenames replace each other. Files in
  79     <filename>/etc</filename> have the highest priority, files in
  80     <filename>/run</filename> take precedence over files with the same
  81     name in <filename>/usr/lib</filename>. This can be used to
  82     override a system-supplied configuration file with a local file if
  83     needed; a symlink in <filename>/etc</filename> with the same name
  84     as a configuration file in <filename>/usr/lib</filename>, pointing
  85     to <filename>/dev/null</filename>, disables the configuration file
  86     entirely.</para>
  87
  88   </refsect1>
  89
  90   <refsect1>
  91     <title>Supported netdev kinds</title>
  92
  93     <para>The following kinds of virtual network devices may be
  94     configured in <filename>.netdev</filename> files:</para>
  95
  96     <table>
  97       <title>Supported kinds of virtual network devices</title>
  98
  99       <tgroup cols='2'>
 100         <colspec colname='kind' />
 101         <colspec colname='explanation' />
 102         <thead><row>
 103           <entry>Kind</entry>
 104           <entry>Description</entry>
 105         </row></thead>
 106         <tbody>
 107           <row><entry><varname>bond</varname></entry>
 108           <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>
 109
 110           <row><entry><varname>bridge</varname></entry>
 111           <entry>A bridge device is a software switch, each of its slave devices and the bridge itself are ports of the switch.</entry></row>
 112
 113           <row><entry><varname>dummy</varname></entry>
 114           <entry>A dummy device drops all packets sent to it.</entry></row>
 115
 116           <row><entry><varname>gre</varname></entry>
 117           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
 118
 119           <row><entry><varname>gretap</varname></entry>
 120           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 121
 122           <row><entry><varname>ip6gre</varname></entry>
 123           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 124
 125           <row><entry><varname>ip6tnl</varname></entry>
 126           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 127
 128           <row><entry><varname>ip6gretap</varname></entry>
 129           <entry>An Level 2 GRE tunnel over IPv6.</entry></row>
 130
 131           <row><entry><varname>ipip</varname></entry>
 132           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 133
 134           <row><entry><varname>ipvlan</varname></entry>
 135           <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 136
 137           <row><entry><varname>macvlan</varname></entry>
 138           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 139
 140           <row><entry><varname>sit</varname></entry>
 141           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 142
 143           <row><entry><varname>tap</varname></entry>
 144           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 145
 146           <row><entry><varname>tun</varname></entry>
 147           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 148
 149           <row><entry><varname>veth</varname></entry>
 150           <entry>An ethernet tunnel between a pair of network devices.</entry></row>
 151
 152           <row><entry><varname>vlan</varname></entry>
 153           <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>
 154
 155           <row><entry><varname>vti</varname></entry>
 156           <entry>An IPv4 over IPSec tunnel.</entry></row>
 157
 158           <row><entry><varname>vti6</varname></entry>
 159           <entry>An IPv6 over IPSec tunnel.</entry></row>
 160
 161           <row><entry><varname>vxlan</varname></entry>
 162           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 163         </tbody>
 164       </tgroup>
 165     </table>
 166
 167   </refsect1>
 168
 169   <refsect1>
 170     <title>[Match] Section Options</title>
 171
 172     <para>A virtual network device is only created if the
 173     <literal>[Match]</literal> section matches the current
 174     environment, or if the section is empty. The following keys are
 175     accepted:</para>
 176
 177     <variablelist class='network-directives'>
 178       <varlistentry>
 179         <term><varname>Host=</varname></term>
 180         <listitem>
 181           <para>Matches against the hostname or machine ID of the
 182           host. See <literal>ConditionHost=</literal> in
 183           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 184           for details.
 185           </para>
 186         </listitem>
 187       </varlistentry>
 188       <varlistentry>
 189         <term><varname>Virtualization=</varname></term>
 190         <listitem>
 191           <para>Checks whether the system is executed in a virtualized
 192           environment and optionally test whether it is a specific
 193           implementation. See
 194           <literal>ConditionVirtualization=</literal> in
 195           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 196           for details.
 197           </para>
 198         </listitem>
 199       </varlistentry>
 200       <varlistentry>
 201         <term><varname>KernelCommandLine=</varname></term>
 202         <listitem>
 203           <para>Checks whether a specific kernel command line option
 204           is set (or if prefixed with the exclamation mark unset). See
 205           <literal>ConditionKernelCommandLine=</literal> in
 206           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 207           for details.
 208           </para>
 209         </listitem>
 210       </varlistentry>
 211       <varlistentry>
 212         <term><varname>Architecture=</varname></term>
 213         <listitem>
 214           <para>Checks whether the system is running on a specific
 215           architecture. See <literal>ConditionArchitecture=</literal> in
 216           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 217           for details.
 218           </para>
 219         </listitem>
 220       </varlistentry>
 221     </variablelist>
 222
 223   </refsect1>
 224
 225   <refsect1>
 226     <title>[NetDev] Section Options</title>
 227
 228       <para>The <literal>[NetDev]</literal> section accepts the
 229       following keys:</para>
 230
 231       <variablelist class='network-directives'>
 232         <varlistentry>
 233           <term><varname>Description=</varname></term>
 234           <listitem>
 235             <para>A free-form description of the netdev.</para>
 236           </listitem>
 237         </varlistentry>
 238         <varlistentry>
 239           <term><varname>Name=</varname></term>
 240           <listitem>
 241             <para>The interface name used when creating the netdev.
 242             This option is compulsory.</para>
 243           </listitem>
 244         </varlistentry>
 245         <varlistentry>
 246           <term><varname>Kind=</varname></term>
 247           <listitem>
 248             <para>The netdev kind. This option is compulsory. See the
 249             <literal>Supported netdev kinds</literal> section for the
 250             valid keys.</para>
 251           </listitem>
 252         </varlistentry>
 253         <varlistentry>
 254           <term><varname>MTUBytes=</varname></term>
 255           <listitem>
 256             <para>The maximum transmission unit in bytes to set for
 257             the device. The usual suffixes K, M, G, are supported and
 258             are understood to the base of 1024. This key is not
 259             currently supported for <literal>tun</literal> or
 260             <literal>tap</literal> devices.
 261             </para>
 262           </listitem>
 263         </varlistentry>
 264         <varlistentry>
 265           <term><varname>MACAddress=</varname></term>
 266           <listitem>
 267             <para>The MAC address to use for the device. If none is
 268             given, one is generated based on the interface name and
 269             the
 270             <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 271             This key is not currently supported for
 272             <literal>tun</literal> or <literal>tap</literal> devices.
 273             </para>
 274           </listitem>
 275         </varlistentry>
 276       </variablelist>
 277   </refsect1>
 278
 279   <refsect1>
 280     <title>[VLAN] Section Options</title>
 281
 282       <para>The <literal>[VLAN]</literal> section only applies for
 283       netdevs of kind <literal>vlan</literal>, and accepts the
 284       following key:</para>
 285
 286       <variablelist class='network-directives'>
 287         <varlistentry>
 288           <term><varname>Id=</varname></term>
 289           <listitem>
 290             <para>The VLAN ID to use. An integer in the range 0–4094.
 291             This option is compulsory.</para>
 292           </listitem>
 293         </varlistentry>
 294       </variablelist>
 295
 296   </refsect1>
 297
 298   <refsect1>
 299     <title>[MACVLAN] Section Options</title>
 300
 301     <para>The <literal>[MACVLAN]</literal> section only applies for
 302     netdevs of kind <literal>macvlan</literal>, and accepts the
 303     following key:</para>
 304
 305     <variablelist class='network-directives'>
 306       <varlistentry>
 307         <term><varname>Mode=</varname></term>
 308         <listitem>
 309           <para>The MACVLAN mode to use. The supported options are
 310           <literal>private</literal>,
 311           <literal>vepa</literal>,
 312           <literal>bridge</literal>, and
 313           <literal>passthru</literal>.
 314           </para>
 315         </listitem>
 316       </varlistentry>
 317     </variablelist>
 318
 319   </refsect1>
 320
 321   <refsect1>
 322     <title>[IPVLAN] Section Options</title>
 323
 324     <para>The <literal>[IPVLAN]</literal> section only applies for
 325     netdevs of kind <literal>ipvlan</literal>, and accepts the
 326     following key:</para>
 327
 328     <variablelist class='network-directives'>
 329       <varlistentry>
 330         <term><varname>Mode=</varname></term>
 331           <listitem>
 332             <para>The IPVLAN mode to use. The supported options are
 333             <literal>L2</literal> and <literal>L3</literal>.
 334             </para>
 335           </listitem>
 336       </varlistentry>
 337     </variablelist>
 338
 339   </refsect1>
 340
 341   <refsect1>
 342     <title>[VXLAN] Section Options</title>
 343     <para>The <literal>[VXLAN]</literal> section only applies for
 344     netdevs of kind <literal>vxlan</literal>, and accepts the
 345     following keys:</para>
 346
 347     <variablelist class='network-directives'>
 348       <varlistentry>
 349         <term><varname>Id=</varname></term>
 350         <listitem>
 351           <para>The VXLAN ID to use.</para>
 352         </listitem>
 353       </varlistentry>
 354       <varlistentry>
 355         <term><varname>Group=</varname></term>
 356         <listitem>
 357           <para>An assigned multicast group IP address.</para>
 358         </listitem>
 359       </varlistentry>
 360       <varlistentry>
 361         <term><varname>TOS=</varname></term>
 362         <listitem>
 363           <para>The Type Of Service byte value for a vxlan interface.</para>
 364         </listitem>
 365       </varlistentry>
 366       <varlistentry>
 367         <term><varname>TTL=</varname></term>
 368         <listitem>
 369           <para>A fixed Time To Live N on Virtual eXtensible Local
 370           Area Network packets. N is a number in the range 1-255. 0
 371           is a special value meaning that packets inherit the TTL
 372           value.</para>
 373         </listitem>
 374       </varlistentry>
 375       <varlistentry>
 376         <term><varname>MacLearning=</varname></term>
 377         <listitem>
 378           <para>A boolean. When true, enables dynamic MAC learning
 379           to discover remote MAC addresses.</para>
 380         </listitem>
 381       </varlistentry>
 382       <varlistentry>
 383         <term><varname>FDBAgeingSec=</varname></term>
 384         <listitem>
 385           <para>The lifetime of Forwarding Database entry learnt by
 386           the kernel in seconds.</para>
 387         </listitem>
 388       </varlistentry>
 389       <varlistentry>
 390         <term><varname>ARPProxy=</varname></term>
 391         <listitem>
 392           <para>A boolean. When true, enables ARP proxy.</para>
 393         </listitem>
 394       </varlistentry>
 395       <varlistentry>
 396         <term><varname>L2MissNotification=</varname></term>
 397         <listitem>
 398           <para>A boolean. When true, enables netlink LLADDR miss
 399           notifications.</para>
 400         </listitem>
 401       </varlistentry>
 402       <varlistentry>
 403         <term><varname>L3MissNotification=</varname></term>
 404         <listitem>
 405           <para>A boolean. When true, enables netlink IP ADDR miss
 406           notifications.</para>
 407         </listitem>
 408       </varlistentry>
 409       <varlistentry>
 410         <term><varname>RouteShortCircuit=</varname></term>
 411         <listitem>
 412           <para>A boolean. When true route short circuit is turned
 413           on.</para>
 414         </listitem>
 415       </varlistentry>
 416       <varlistentry>
 417         <term><varname>UDPCheckSum=</varname></term>
 418         <listitem>
 419           <para>A boolean. When true transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 420         </listitem>
 421       </varlistentry>
 422       <varlistentry>
 423         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 424         <listitem>
 425           <para>A boolean. When true sending zero checksums in VXLAN/IPv6 is turned on.</para>
 426         </listitem>
 427       </varlistentry>
 428       <varlistentry>
 429         <term><varname>UDP6ZeroCheckSumRx=</varname></term>
 430         <listitem>
 431           <para>A boolean. When true receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 432         </listitem>
 433       </varlistentry>
 434     </variablelist>
 435   </refsect1>
 436   <refsect1>
 437     <title>[Tunnel] Section Options</title>
 438
 439     <para>The <literal>[Tunnel]</literal> section only applies for
 440     netdevs of kind
 441     <literal>ipip</literal>,
 442     <literal>sit</literal>,
 443     <literal>gre</literal>,
 444     <literal>gretap</literal>,
 445     <literal>ip6gre</literal>,
 446     <literal>ip6gretap</literal>,
 447     <literal>vti</literal>,
 448     <literal>vti6</literal>, and
 449     <literal>ip6tnl</literal> and accepts
 450     the following keys:</para>
 451
 452     <variablelist class='network-directives'>
 453       <varlistentry>
 454         <term><varname>Local=</varname></term>
 455         <listitem>
 456           <para>A static local address for tunneled packets. It must
 457           be an address on another interface of this host.</para>
 458         </listitem>
 459       </varlistentry>
 460       <varlistentry>
 461         <term><varname>Remote=</varname></term>
 462         <listitem>
 463           <para>The remote endpoint of the tunnel.</para>
 464         </listitem>
 465       </varlistentry>
 466       <varlistentry>
 467         <term><varname>TOS=</varname></term>
 468         <listitem>
 469           <para>The Type Of Service byte value for a tunnel interface.
 470           For details about the TOS see the
 471           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
 472           Service in the Internet Protocol Suite </ulink> document.
 473           </para>
 474         </listitem>
 475       </varlistentry>
 476       <varlistentry>
 477         <term><varname>TTL=</varname></term>
 478         <listitem>
 479           <para>A fixed Time To Live N on tunneled packets. N is a
 480           number in the range 1-255. 0 is a special value meaning that
 481           packets inherit the TTL value. The default value for IPv4
 482           tunnels is: inherit. The default value for IPv6 tunnels is:
 483           64.</para>
 484         </listitem>
 485       </varlistentry>
 486       <varlistentry>
 487         <term><varname>DiscoverPathMTU=</varname></term>
 488         <listitem>
 489           <para>A boolean. When true, enables Path MTU Discovery on
 490           the tunnel.</para>
 491         </listitem>
 492       </varlistentry>
 493       <varlistentry>
 494         <term><varname>Mode=</varname></term>
 495         <listitem>
 496           <para>An <literal>ip6tnl</literal> tunnels can have three
 497           modes
 498           <literal>ip6ip6</literal> for IPv6 over IPv6,
 499           <literal>ipip6</literal> for IPv4 over IPv6 or
 500           <literal>any</literal> for either.
 501           </para>
 502         </listitem>
 503       </varlistentry>
 504     </variablelist>
 505   </refsect1>
 506   <refsect1>
 507     <title>[Peer] Section Options</title>
 508
 509       <para>The <literal>[Peer]</literal> section only applies for
 510       netdevs of kind <literal>veth</literal> and accepts the
 511       following key:</para>
 512
 513       <variablelist class='network-directives'>
 514         <varlistentry>
 515           <term><varname>Name=</varname></term>
 516           <listitem>
 517             <para>The interface name used when creating the netdev.
 518             This option is compulsory.</para>
 519           </listitem>
 520         </varlistentry>
 521         <varlistentry>
 522           <term><varname>MACAddress=</varname></term>
 523           <listitem>
 524             <para>The peer MACAddress, if not set it is generated in
 525             the same way as the MAC address of the main
 526             interface.</para>
 527           </listitem>
 528         </varlistentry>
 529       </variablelist>
 530   </refsect1>
 531   <refsect1>
 532     <title>[Tun] Section Options</title>
 533
 534     <para>The <literal>[Tun]</literal> section only applies for
 535     netdevs of kind <literal>tun</literal>, and accepts the following
 536     keys:</para>
 537
 538     <variablelist class='network-directives'>
 539       <varlistentry>
 540         <term><varname>OneQueue=</varname></term>
 541         <listitem><para>Takes a boolean argument. Configures whether
 542         all packets are queued at the device (enabled), or a fixed
 543         number of packets are queued at the device and the rest at the
 544         <literal>qdisc</literal>. Defaults to
 545         <literal>no</literal>.</para>
 546         </listitem>
 547       </varlistentry>
 548       <varlistentry>
 549         <term><varname>MultiQueue=</varname></term>
 550         <listitem><para>Takes a boolean argument. Configures whether
 551         to use multiple file descriptors (queues) to parallelize
 552         packets sending and receiving. Defaults to
 553         <literal>no</literal>.</para>
 554         </listitem>
 555       </varlistentry>
 556       <varlistentry>
 557         <term><varname>PacketInfo=</varname></term>
 558         <listitem><para>Takes a boolean argument. Configures whether
 559         packets should be prepended with four extra bytes (two flag
 560         bytes and two protocol bytes). If disabled it indicates that
 561         the packets will be pure IP packets. Defaults to
 562         <literal>no</literal>.</para>
 563         </listitem>
 564       </varlistentry>
 565       <varlistentry>
 566         <term><varname>User=</varname></term>
 567         <listitem><para>User to grant access to the
 568         <filename>/dev/net/tun</filename> device.</para>
 569         </listitem>
 570       </varlistentry>
 571       <varlistentry>
 572         <term><varname>Group=</varname></term>
 573         <listitem><para>Group to grant access to the
 574         <filename>/dev/net/tun</filename> device.</para>
 575         </listitem>
 576       </varlistentry>
 577
 578     </variablelist>
 579
 580   </refsect1>
 581
 582   <refsect1>
 583     <title>[Tap] Section Options</title>
 584
 585     <para>The <literal>[Tap]</literal> section only applies for
 586     netdevs of kind <literal>tap</literal>, and accepts the same keys
 587     as the <literal>[Tun]</literal> section.</para>
 588   </refsect1>
 589
 590   <refsect1>
 591     <title>[Bond] Section Options</title>
 592
 593     <para>The <literal>[Bond]</literal> section accepts the following
 594     key:</para>
 595
 596     <variablelist class='network-directives'>
 597       <varlistentry>
 598         <term><varname>Mode=</varname></term>
 599         <listitem>
 600           <para>Specifies one of the bonding policies. The default is
 601           <literal>balance-rr</literal> (round robin). Possible values are
 602           <literal>balance-rr</literal>,
 603           <literal>active-backup</literal>,
 604           <literal>balance-xor</literal>,
 605           <literal>broadcast</literal>,
 606           <literal>802.3ad</literal>,
 607           <literal>balance-tlb</literal>, and
 608           <literal>balance-alb</literal>.
 609           </para>
 610         </listitem>
 611       </varlistentry>
 612
 613       <varlistentry>
 614         <term><varname>TransmitHashPolicy=</varname></term>
 615         <listitem>
 616           <para>Selects the transmit hash policy to use for slave
 617           selection in balance-xor, 802.3ad, and tlb modes. Possible
 618           values are
 619           <literal>layer2</literal>,
 620           <literal>layer3+4</literal>,
 621           <literal>layer2+3</literal>,
 622           <literal>encap2+3</literal>,
 623           <literal>802.3ad</literal>, and
 624           <literal>encap3+4</literal>.
 625           </para>
 626         </listitem>
 627       </varlistentry>
 628
 629       <varlistentry>
 630         <term><varname>LACPTransmitRate=</varname></term>
 631         <listitem>
 632           <para>Specifies the rate with which link partner transmits
 633           Link Aggregation Control Protocol Data Unit packets in
 634           802.3ad mode. Possible values are <literal>slow</literal>,
 635           which requests partner to transmit LACPDUs every 30 seconds,
 636           and <literal>fast</literal>, which requests partner to
 637           transmit LACPDUs every second. The default value is
 638           <literal>slow</literal>.</para>
 639         </listitem>
 640       </varlistentry>
 641
 642       <varlistentry>
 643         <term><varname>MIIMonitorSec=</varname></term>
 644         <listitem>
 645           <para>Specifies the frequency that Media Independent
 646           Interface link monitoring will occur. A value of zero
 647           disables MII link monitoring. This values is rounded down to
 648           the nearest millisecond. The default value is 0.</para>
 649         </listitem>
 650       </varlistentry>
 651
 652       <varlistentry>
 653         <term><varname>UpDelaySec=</varname></term>
 654         <listitem>
 655           <para>Specifies the delay before a link is enabled after a
 656           link up status has been detected. This value is rounded down
 657           to a multiple of MIIMonitorSec. The default value is
 658           0.</para>
 659         </listitem>
 660       </varlistentry>
 661
 662       <varlistentry>
 663         <term><varname>DownDelaySec=</varname></term>
 664         <listitem>
 665           <para>Specifies the delay before a link is disabled after a
 666           link down status has been detected. This value is rounded
 667           down to a multiple of MIIMonitorSec. The default value is
 668           0.</para>
 669         </listitem>
 670       </varlistentry>
 671
 672       <varlistentry>
 673         <term><varname>LearnPacketIntervalSec=</varname></term>
 674         <listitem>
 675           <para>Specifies the number of seconds between instances where the bonding
 676           driver sends learning packets to each slaves peer switch.
 677           The valid range is 1 - 0x7fffffff; the default value is 1. This Option
 678           has effect only in balance-tlb and balance-alb modes.</para>
 679         </listitem>
 680       </varlistentry>
 681
 682       <varlistentry>
 683         <term><varname>AdSelect=</varname></term>
 684         <listitem>
 685           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
 686           <literal>stable</literal>,
 687           <literal>bandwidth</literal>,
 688           <literal>count</literal>
 689           </para>
 690         </listitem>
 691       </varlistentry>
 692
 693       <varlistentry>
 694         <term><varname>FailOverMACPolicy=</varname></term>
 695         <listitem>
 696           <para>Specifies whether active-backup mode should set all slaves to
 697           the same MAC address at enslavement or, when enabled, perform special handling of the
 698           bond's MAC address in accordance with the selected policy. The default policy is none.
 699           Possible values are
 700           <literal>none</literal>,
 701           <literal>active</literal>,
 702           <literal>follow</literal>
 703           </para>
 704         </listitem>
 705       </varlistentry>
 706
 707       <varlistentry>
 708         <term><varname>ARPValidate=</varname></term>
 709         <listitem>
 710           <para>Specifies whether or not ARP probes and replies should be
 711           validated in any mode that supports ARP monitoring, or whether
 712           non-ARP traffic should be filtered (disregarded) for link
 713           monitoring purposes. Possible values are
 714           <literal>none</literal>,
 715           <literal>active</literal>,
 716           <literal>backup</literal>,
 717           <literal>all</literal>
 718           </para>
 719         </listitem>
 720       </varlistentry>
 721
 722       <varlistentry>
 723         <term><varname>ARPIntervalSec=</varname></term>
 724         <listitem>
 725           <para>Specifies the ARP link monitoring frequency in milliseconds.
 726           A value of 0 disables ARP monitoring. The default value is 0.
 727           </para>
 728         </listitem>
 729       </varlistentry>
 730
 731       <varlistentry>
 732         <term><varname>ARPIPTargets=</varname></term>
 733         <listitem>
 734           <para>Specifies the IP addresses to use as ARP monitoring peers when
 735           ARPIntervalSec is greater than 0. These are the targets of the ARP request
 736           sent to determine the health of the link to the targets.
 737           Specify these values in ipv4 dotted decimal format. At least one IP
 738           address must be given for ARP monitoring to function. The
 739           maximum number of targets that can be specified is 16. The
 740           default value is no IP addresses.
 741           </para>
 742         </listitem>
 743       </varlistentry>
 744
 745       <varlistentry>
 746         <term><varname>ARPAllTargets=</varname></term>
 747         <listitem>
 748           <para>Specifies the quantity of ARPIPTargets that must be reachable
 749           in order for the ARP monitor to consider a slave as being up.
 750           This option affects only active-backup mode for slaves with
 751           ARPValidate enabled. Possible values are
 752           <literal>any</literal>,
 753           <literal>all</literal>
 754           </para>
 755         </listitem>
 756       </varlistentry>
 757
 758       <varlistentry>
 759         <term><varname>PrimaryReselectPolicy=</varname></term>
 760         <listitem>
 761           <para>Specifies the reselection policy for the primary slave.  This
 762           affects how the primary slave is chosen to become the active slave
 763           when failure of the active slave or recovery of the primary slave
 764           occurs. This option is designed to prevent flip-flopping between
 765           the primary slave and other slaves.  Possible values are
 766           <literal>always</literal>,
 767           <literal>better</literal>,
 768           <literal>failure</literal>
 769           </para>
 770         </listitem>
 771       </varlistentry>
 772
 773       <varlistentry>
 774         <term><varname>ResendIGMP=</varname></term>
 775         <listitem>
 776           <para>Specifies the number of IGMP membership reports to be issued after
 777           a failover event. One membership report is issued immediately after
 778           the failover, subsequent packets are sent in each 200ms interval.
 779           The valid range is (0 - 255). Defaults to 1. A value of 0
 780           prevents the IGMP membership report from being issued in response
 781           to the failover event.
 782           </para>
 783         </listitem>
 784       </varlistentry>
 785
 786       <varlistentry>
 787         <term><varname>PacketsPerSlave=</varname></term>
 788         <listitem>
 789           <para> Specify the number of packets to transmit through a slave before
 790             moving to the next one. When set to 0 then a slave is chosen at
 791             random.The valid range is (0 - 65535). Defaults to 1. This option
 792             has effect only in balance-rr mode.
 793           </para>
 794         </listitem>
 795       </varlistentry>
 796
 797       <varlistentry>
 798         <term><varname>GratuitousARP=</varname></term>
 799         <listitem>
 800           <para>Specify the number of peer notifications (gratuitous ARPs and
 801             unsolicited IPv6 Neighbor Advertisements) to be issued after a
 802             failover event.  As soon as the link is up on the new slave
 803             a peer notification is sent on the  bonding device and each
 804             VLAN sub-device.  This is repeated at each link monitor interval
 805             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
 806             greater than 1. The valid range is (0 - 255). Default value is 1.
 807             These options affect only the active-backup mode.
 808           </para>
 809         </listitem>
 810       </varlistentry>
 811
 812       <varlistentry>
 813         <term><varname>AllSlavesActive=</varname></term>
 814         <listitem>
 815           <para> A boolean. Specifies that duplicate frames (received on inactive ports)
 816           should be dropped false or delivered true. Normally, bonding will drop
 817           duplicate frames (received on inactive ports), which is desirable for
 818           most users. But there are some times it is nice to allow duplicate
 819           frames to be delivered. The default value is false (drop duplicate frames
 820           received on inactive ports).
 821           </para>
 822         </listitem>
 823       </varlistentry>
 824
 825       <varlistentry>
 826         <term><varname>MinLinks=</varname></term>
 827         <listitem>
 828           <para>Specifies the minimum number of links that must be active before
 829           asserting carrier. The default value is 0.
 830           </para>
 831         </listitem>
 832       </varlistentry>
 833
 834     </variablelist>
 835
 836     <para>For more detail information see
 837     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
 838     Linux Ethernet Bonding Driver HOWTO</ulink></para>
 839
 840   </refsect1>
 841
 842   <refsect1>
 843     <title>Example</title>
 844     <example>
 845       <title>/etc/systemd/network/bridge.netdev</title>
 846
 847       <programlisting>[NetDev]
 848 Name=bridge0
 849 Kind=bridge</programlisting>
 850     </example>
 851
 852     <example>
 853       <title>/etc/systemd/network/vlan1.netdev</title>
 854
 855       <programlisting>[Match]
 856 Virtualization=no
 857
 858 [NetDev]
 859 Name=vlan1
 860 Kind=vlan
 861
 862 [VLAN]
 863 Id=1</programlisting>
 864     </example>
 865     <example>
 866       <title>/etc/systemd/network/ipip.netdev</title>
 867       <programlisting>[NetDev]
 868 Name=ipip-tun
 869 Kind=ipip
 870 MTUBytes=1480
 871
 872 [Tunnel]
 873 Local=192.168.223.238
 874 Remote=192.169.224.239
 875 TTL=64</programlisting>
 876     </example>
 877     <example>
 878       <title>/etc/systemd/network/tap.netdev</title>
 879       <programlisting>[NetDev]
 880 Name=tap-test
 881 Kind=tap
 882
 883 [Tap]
 884 MultiQueue=true
 885 PacketInfo=true</programlisting> </example>
 886
 887     <example>
 888       <title>/etc/systemd/network/sit.netdev</title>
 889       <programlisting>[NetDev]
 890 Name=sit-tun
 891 Kind=sit
 892 MTUBytes=1480
 893
 894 [Tunnel]
 895 Local=10.65.223.238
 896 Remote=10.65.223.239</programlisting>
 897     </example>
 898
 899     <example>
 900       <title>/etc/systemd/network/gre.netdev</title>
 901       <programlisting>[NetDev]
 902 Name=gre-tun
 903 Kind=gre
 904 MTUBytes=1480
 905
 906 [Tunnel]
 907 Local=10.65.223.238
 908 Remote=10.65.223.239</programlisting>
 909     </example>
 910
 911     <example>
 912       <title>/etc/systemd/network/vti.netdev</title>
 913
 914       <programlisting>[NetDev]
 915 Name=vti-tun
 916 Kind=vti
 917 MTUBytes=1480
 918
 919 [Tunnel]
 920 Local=10.65.223.238
 921 Remote=10.65.223.239</programlisting>
 922     </example>
 923
 924     <example>
 925       <title>/etc/systemd/network/veth.netdev</title>
 926       <programlisting>[NetDev]
 927 Name=veth-test
 928 Kind=veth
 929
 930 [Peer]
 931 Name=veth-peer</programlisting>
 932     </example>
 933
 934     <example>
 935       <title>/etc/systemd/network/dummy.netdev</title>
 936       <programlisting>[NetDev]
 937 Name=dummy-test
 938 Kind=dummy
 939 MACAddress=12:34:56:78:9a:bc</programlisting>
 940     </example>
 941
 942   </refsect1>
 943   <refsect1>
 944     <title>See Also</title>
 945     <para>
 946       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 947       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 948       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 949       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 950     </para>
 951   </refsect1>
 952
 953 </refentry>