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>IPv6FlowLabel=</varname></term>
 495         <listitem>
 496           <para>Configures The 20-bit Flow Label (see <ulink url="https://tools.ietf.org/html/rfc6437">
 497           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
 498           RFC 2460</ulink>), is used by a node to label packets of a flow.
 499           It's only used for IPv6 Tunnels.
 500           A Flow Label of zero is used to indicate packets that have
 501           not been labeled. Takes following values.
 502           When <literal>inherit</literal> it uses the original flowlabel,
 503           or can be configured to any value betwen 0 to 0xFFFFF.</para>
 504         </listitem>
 505       </varlistentry>
 506       <varlistentry>
 507         <term><varname>DiffServiceCodePoint=</varname></term>
 508         <listitem>
 509           <para>A boolean. When true, inherits the Differentiated
 510           Service Code Point (DSCP) field between inner and outer
 511           header for ip6_tunnel. DSCP is a field in an IP packet
 512           that enables different levels of service to be assigned
 513           to network traffic. Defaults to <literal>no</literal>.
 514           </para>
 515         </listitem>
 516       </varlistentry>
 517       <varlistentry>
 518         <term><varname>Mode=</varname></term>
 519         <listitem>
 520           <para>An <literal>ip6tnl</literal> tunnels can have three
 521           modes
 522           <literal>ip6ip6</literal> for IPv6 over IPv6,
 523           <literal>ipip6</literal> for IPv4 over IPv6 or
 524           <literal>any</literal> for either.
 525           </para>
 526         </listitem>
 527       </varlistentry>
 528     </variablelist>
 529   </refsect1>
 530   <refsect1>
 531     <title>[Peer] Section Options</title>
 532
 533       <para>The <literal>[Peer]</literal> section only applies for
 534       netdevs of kind <literal>veth</literal> and accepts the
 535       following key:</para>
 536
 537       <variablelist class='network-directives'>
 538         <varlistentry>
 539           <term><varname>Name=</varname></term>
 540           <listitem>
 541             <para>The interface name used when creating the netdev.
 542             This option is compulsory.</para>
 543           </listitem>
 544         </varlistentry>
 545         <varlistentry>
 546           <term><varname>MACAddress=</varname></term>
 547           <listitem>
 548             <para>The peer MACAddress, if not set it is generated in
 549             the same way as the MAC address of the main
 550             interface.</para>
 551           </listitem>
 552         </varlistentry>
 553       </variablelist>
 554   </refsect1>
 555   <refsect1>
 556     <title>[Tun] Section Options</title>
 557
 558     <para>The <literal>[Tun]</literal> section only applies for
 559     netdevs of kind <literal>tun</literal>, and accepts the following
 560     keys:</para>
 561
 562     <variablelist class='network-directives'>
 563       <varlistentry>
 564         <term><varname>OneQueue=</varname></term>
 565         <listitem><para>Takes a boolean argument. Configures whether
 566         all packets are queued at the device (enabled), or a fixed
 567         number of packets are queued at the device and the rest at the
 568         <literal>qdisc</literal>. Defaults to
 569         <literal>no</literal>.</para>
 570         </listitem>
 571       </varlistentry>
 572       <varlistentry>
 573         <term><varname>MultiQueue=</varname></term>
 574         <listitem><para>Takes a boolean argument. Configures whether
 575         to use multiple file descriptors (queues) to parallelize
 576         packets sending and receiving. Defaults to
 577         <literal>no</literal>.</para>
 578         </listitem>
 579       </varlistentry>
 580       <varlistentry>
 581         <term><varname>PacketInfo=</varname></term>
 582         <listitem><para>Takes a boolean argument. Configures whether
 583         packets should be prepended with four extra bytes (two flag
 584         bytes and two protocol bytes). If disabled it indicates that
 585         the packets will be pure IP packets. Defaults to
 586         <literal>no</literal>.</para>
 587         </listitem>
 588       </varlistentry>
 589       <varlistentry>
 590         <term><varname>VnetHeader=</varname></term>
 591         <listitem><para>Takes a boolean argument. Configures
 592         IFF_VNET_HDR flag for a tap device. It allows sending
 593         and receiving larger Generic Segmentation Offload (GSO)
 594         packets. This may increase throughput significantly.
 595         Defaults to
 596         <literal>no</literal>.</para>
 597         </listitem>
 598       </varlistentry>
 599       <varlistentry>
 600         <term><varname>User=</varname></term>
 601         <listitem><para>User to grant access to the
 602         <filename>/dev/net/tun</filename> device.</para>
 603         </listitem>
 604       </varlistentry>
 605       <varlistentry>
 606         <term><varname>Group=</varname></term>
 607         <listitem><para>Group to grant access to the
 608         <filename>/dev/net/tun</filename> device.</para>
 609         </listitem>
 610       </varlistentry>
 611
 612     </variablelist>
 613
 614   </refsect1>
 615
 616   <refsect1>
 617     <title>[Tap] Section Options</title>
 618
 619     <para>The <literal>[Tap]</literal> section only applies for
 620     netdevs of kind <literal>tap</literal>, and accepts the same keys
 621     as the <literal>[Tun]</literal> section.</para>
 622   </refsect1>
 623
 624   <refsect1>
 625     <title>[Bond] Section Options</title>
 626
 627     <para>The <literal>[Bond]</literal> section accepts the following
 628     key:</para>
 629
 630     <variablelist class='network-directives'>
 631       <varlistentry>
 632         <term><varname>Mode=</varname></term>
 633         <listitem>
 634           <para>Specifies one of the bonding policies. The default is
 635           <literal>balance-rr</literal> (round robin). Possible values are
 636           <literal>balance-rr</literal>,
 637           <literal>active-backup</literal>,
 638           <literal>balance-xor</literal>,
 639           <literal>broadcast</literal>,
 640           <literal>802.3ad</literal>,
 641           <literal>balance-tlb</literal>, and
 642           <literal>balance-alb</literal>.
 643           </para>
 644         </listitem>
 645       </varlistentry>
 646
 647       <varlistentry>
 648         <term><varname>TransmitHashPolicy=</varname></term>
 649         <listitem>
 650           <para>Selects the transmit hash policy to use for slave
 651           selection in balance-xor, 802.3ad, and tlb modes. Possible
 652           values are
 653           <literal>layer2</literal>,
 654           <literal>layer3+4</literal>,
 655           <literal>layer2+3</literal>,
 656           <literal>encap2+3</literal>,
 657           <literal>802.3ad</literal>, and
 658           <literal>encap3+4</literal>.
 659           </para>
 660         </listitem>
 661       </varlistentry>
 662
 663       <varlistentry>
 664         <term><varname>LACPTransmitRate=</varname></term>
 665         <listitem>
 666           <para>Specifies the rate with which link partner transmits
 667           Link Aggregation Control Protocol Data Unit packets in
 668           802.3ad mode. Possible values are <literal>slow</literal>,
 669           which requests partner to transmit LACPDUs every 30 seconds,
 670           and <literal>fast</literal>, which requests partner to
 671           transmit LACPDUs every second. The default value is
 672           <literal>slow</literal>.</para>
 673         </listitem>
 674       </varlistentry>
 675
 676       <varlistentry>
 677         <term><varname>MIIMonitorSec=</varname></term>
 678         <listitem>
 679           <para>Specifies the frequency that Media Independent
 680           Interface link monitoring will occur. A value of zero
 681           disables MII link monitoring. This values is rounded down to
 682           the nearest millisecond. The default value is 0.</para>
 683         </listitem>
 684       </varlistentry>
 685
 686       <varlistentry>
 687         <term><varname>UpDelaySec=</varname></term>
 688         <listitem>
 689           <para>Specifies the delay before a link is enabled after a
 690           link up status has been detected. This value is rounded down
 691           to a multiple of MIIMonitorSec. The default value is
 692           0.</para>
 693         </listitem>
 694       </varlistentry>
 695
 696       <varlistentry>
 697         <term><varname>DownDelaySec=</varname></term>
 698         <listitem>
 699           <para>Specifies the delay before a link is disabled after a
 700           link down status has been detected. This value is rounded
 701           down to a multiple of MIIMonitorSec. The default value is
 702           0.</para>
 703         </listitem>
 704       </varlistentry>
 705
 706       <varlistentry>
 707         <term><varname>LearnPacketIntervalSec=</varname></term>
 708         <listitem>
 709           <para>Specifies the number of seconds between instances where the bonding
 710           driver sends learning packets to each slaves peer switch.
 711           The valid range is 1 - 0x7fffffff; the default value is 1. This Option
 712           has effect only in balance-tlb and balance-alb modes.</para>
 713         </listitem>
 714       </varlistentry>
 715
 716       <varlistentry>
 717         <term><varname>AdSelect=</varname></term>
 718         <listitem>
 719           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
 720           <literal>stable</literal>,
 721           <literal>bandwidth</literal>,
 722           <literal>count</literal>
 723           </para>
 724         </listitem>
 725       </varlistentry>
 726
 727       <varlistentry>
 728         <term><varname>FailOverMACPolicy=</varname></term>
 729         <listitem>
 730           <para>Specifies whether active-backup mode should set all slaves to
 731           the same MAC address at enslavement or, when enabled, perform special handling of the
 732           bond's MAC address in accordance with the selected policy. The default policy is none.
 733           Possible values are
 734           <literal>none</literal>,
 735           <literal>active</literal>,
 736           <literal>follow</literal>
 737           </para>
 738         </listitem>
 739       </varlistentry>
 740
 741       <varlistentry>
 742         <term><varname>ARPValidate=</varname></term>
 743         <listitem>
 744           <para>Specifies whether or not ARP probes and replies should be
 745           validated in any mode that supports ARP monitoring, or whether
 746           non-ARP traffic should be filtered (disregarded) for link
 747           monitoring purposes. Possible values are
 748           <literal>none</literal>,
 749           <literal>active</literal>,
 750           <literal>backup</literal>,
 751           <literal>all</literal>
 752           </para>
 753         </listitem>
 754       </varlistentry>
 755
 756       <varlistentry>
 757         <term><varname>ARPIntervalSec=</varname></term>
 758         <listitem>
 759           <para>Specifies the ARP link monitoring frequency in milliseconds.
 760           A value of 0 disables ARP monitoring. The default value is 0.
 761           </para>
 762         </listitem>
 763       </varlistentry>
 764
 765       <varlistentry>
 766         <term><varname>ARPIPTargets=</varname></term>
 767         <listitem>
 768           <para>Specifies the IP addresses to use as ARP monitoring peers when
 769           ARPIntervalSec is greater than 0. These are the targets of the ARP request
 770           sent to determine the health of the link to the targets.
 771           Specify these values in ipv4 dotted decimal format. At least one IP
 772           address must be given for ARP monitoring to function. The
 773           maximum number of targets that can be specified is 16. The
 774           default value is no IP addresses.
 775           </para>
 776         </listitem>
 777       </varlistentry>
 778
 779       <varlistentry>
 780         <term><varname>ARPAllTargets=</varname></term>
 781         <listitem>
 782           <para>Specifies the quantity of ARPIPTargets that must be reachable
 783           in order for the ARP monitor to consider a slave as being up.
 784           This option affects only active-backup mode for slaves with
 785           ARPValidate enabled. Possible values are
 786           <literal>any</literal>,
 787           <literal>all</literal>
 788           </para>
 789         </listitem>
 790       </varlistentry>
 791
 792       <varlistentry>
 793         <term><varname>PrimaryReselectPolicy=</varname></term>
 794         <listitem>
 795           <para>Specifies the reselection policy for the primary slave.  This
 796           affects how the primary slave is chosen to become the active slave
 797           when failure of the active slave or recovery of the primary slave
 798           occurs. This option is designed to prevent flip-flopping between
 799           the primary slave and other slaves.  Possible values are
 800           <literal>always</literal>,
 801           <literal>better</literal>,
 802           <literal>failure</literal>
 803           </para>
 804         </listitem>
 805       </varlistentry>
 806
 807       <varlistentry>
 808         <term><varname>ResendIGMP=</varname></term>
 809         <listitem>
 810           <para>Specifies the number of IGMP membership reports to be issued after
 811           a failover event. One membership report is issued immediately after
 812           the failover, subsequent packets are sent in each 200ms interval.
 813           The valid range is (0 - 255). Defaults to 1. A value of 0
 814           prevents the IGMP membership report from being issued in response
 815           to the failover event.
 816           </para>
 817         </listitem>
 818       </varlistentry>
 819
 820       <varlistentry>
 821         <term><varname>PacketsPerSlave=</varname></term>
 822         <listitem>
 823           <para> Specify the number of packets to transmit through a slave before
 824             moving to the next one. When set to 0 then a slave is chosen at
 825             random.The valid range is (0 - 65535). Defaults to 1. This option
 826             has effect only in balance-rr mode.
 827           </para>
 828         </listitem>
 829       </varlistentry>
 830
 831       <varlistentry>
 832         <term><varname>GratuitousARP=</varname></term>
 833         <listitem>
 834           <para>Specify the number of peer notifications (gratuitous ARPs and
 835             unsolicited IPv6 Neighbor Advertisements) to be issued after a
 836             failover event.  As soon as the link is up on the new slave
 837             a peer notification is sent on the  bonding device and each
 838             VLAN sub-device.  This is repeated at each link monitor interval
 839             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
 840             greater than 1. The valid range is (0 - 255). Default value is 1.
 841             These options affect only the active-backup mode.
 842           </para>
 843         </listitem>
 844       </varlistentry>
 845
 846       <varlistentry>
 847         <term><varname>AllSlavesActive=</varname></term>
 848         <listitem>
 849           <para> A boolean. Specifies that duplicate frames (received on inactive ports)
 850           should be dropped false or delivered true. Normally, bonding will drop
 851           duplicate frames (received on inactive ports), which is desirable for
 852           most users. But there are some times it is nice to allow duplicate
 853           frames to be delivered. The default value is false (drop duplicate frames
 854           received on inactive ports).
 855           </para>
 856         </listitem>
 857       </varlistentry>
 858
 859       <varlistentry>
 860         <term><varname>MinLinks=</varname></term>
 861         <listitem>
 862           <para>Specifies the minimum number of links that must be active before
 863           asserting carrier. The default value is 0.
 864           </para>
 865         </listitem>
 866       </varlistentry>
 867
 868     </variablelist>
 869
 870     <para>For more detail information see
 871     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
 872     Linux Ethernet Bonding Driver HOWTO</ulink></para>
 873
 874   </refsect1>
 875
 876   <refsect1>
 877     <title>Example</title>
 878     <example>
 879       <title>/etc/systemd/network/bridge.netdev</title>
 880
 881       <programlisting>[NetDev]
 882 Name=bridge0
 883 Kind=bridge</programlisting>
 884     </example>
 885
 886     <example>
 887       <title>/etc/systemd/network/vlan1.netdev</title>
 888
 889       <programlisting>[Match]
 890 Virtualization=no
 891
 892 [NetDev]
 893 Name=vlan1
 894 Kind=vlan
 895
 896 [VLAN]
 897 Id=1</programlisting>
 898     </example>
 899     <example>
 900       <title>/etc/systemd/network/ipip.netdev</title>
 901       <programlisting>[NetDev]
 902 Name=ipip-tun
 903 Kind=ipip
 904 MTUBytes=1480
 905
 906 [Tunnel]
 907 Local=192.168.223.238
 908 Remote=192.169.224.239
 909 TTL=64</programlisting>
 910     </example>
 911     <example>
 912       <title>/etc/systemd/network/tap.netdev</title>
 913       <programlisting>[NetDev]
 914 Name=tap-test
 915 Kind=tap
 916
 917 [Tap]
 918 MultiQueue=true
 919 PacketInfo=true</programlisting> </example>
 920
 921     <example>
 922       <title>/etc/systemd/network/sit.netdev</title>
 923       <programlisting>[NetDev]
 924 Name=sit-tun
 925 Kind=sit
 926 MTUBytes=1480
 927
 928 [Tunnel]
 929 Local=10.65.223.238
 930 Remote=10.65.223.239</programlisting>
 931     </example>
 932
 933     <example>
 934       <title>/etc/systemd/network/gre.netdev</title>
 935       <programlisting>[NetDev]
 936 Name=gre-tun
 937 Kind=gre
 938 MTUBytes=1480
 939
 940 [Tunnel]
 941 Local=10.65.223.238
 942 Remote=10.65.223.239</programlisting>
 943     </example>
 944
 945     <example>
 946       <title>/etc/systemd/network/vti.netdev</title>
 947
 948       <programlisting>[NetDev]
 949 Name=vti-tun
 950 Kind=vti
 951 MTUBytes=1480
 952
 953 [Tunnel]
 954 Local=10.65.223.238
 955 Remote=10.65.223.239</programlisting>
 956     </example>
 957
 958     <example>
 959       <title>/etc/systemd/network/veth.netdev</title>
 960       <programlisting>[NetDev]
 961 Name=veth-test
 962 Kind=veth
 963
 964 [Peer]
 965 Name=veth-peer</programlisting>
 966     </example>
 967
 968     <example>
 969       <title>/etc/systemd/network/dummy.netdev</title>
 970       <programlisting>[NetDev]
 971 Name=dummy-test
 972 Kind=dummy
 973 MACAddress=12:34:56:78:9a:bc</programlisting>
 974     </example>
 975
 976   </refsect1>
 977   <refsect1>
 978     <title>See Also</title>
 979     <para>
 980       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 981       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 982       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 983       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 984     </para>
 985   </refsect1>
 986
 987 </refentry>