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. As a special case, an empty file (file size 0) or symlink
  84     with the same name pointing to <filename>/dev/null</filename>,
  85     disable the configuration file entirely (it is "masked").</para>
  86   </refsect1>
  87
  88   <refsect1>
  89     <title>Supported netdev kinds</title>
  90
  91     <para>The following kinds of virtual network devices may be
  92     configured in <filename>.netdev</filename> files:</para>
  93
  94     <table>
  95       <title>Supported kinds of virtual network devices</title>
  96
  97       <tgroup cols='2'>
  98         <colspec colname='kind' />
  99         <colspec colname='explanation' />
 100         <thead><row>
 101           <entry>Kind</entry>
 102           <entry>Description</entry>
 103         </row></thead>
 104         <tbody>
 105           <row><entry><varname>bond</varname></entry>
 106           <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>
 107
 108           <row><entry><varname>bridge</varname></entry>
 109           <entry>A bridge device is a software switch, each of its slave devices and the bridge itself are ports of the switch.</entry></row>
 110
 111           <row><entry><varname>dummy</varname></entry>
 112           <entry>A dummy device drops all packets sent to it.</entry></row>
 113
 114           <row><entry><varname>gre</varname></entry>
 115           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
 116
 117           <row><entry><varname>gretap</varname></entry>
 118           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 119
 120           <row><entry><varname>ip6gre</varname></entry>
 121           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 122
 123           <row><entry><varname>ip6tnl</varname></entry>
 124           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 125
 126           <row><entry><varname>ip6gretap</varname></entry>
 127           <entry>An Level 2 GRE tunnel over IPv6.</entry></row>
 128
 129           <row><entry><varname>ipip</varname></entry>
 130           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 131
 132           <row><entry><varname>ipvlan</varname></entry>
 133           <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 134
 135           <row><entry><varname>macvlan</varname></entry>
 136           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 137
 138           <row><entry><varname>macvtap</varname></entry>
 139           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 140
 141           <row><entry><varname>sit</varname></entry>
 142           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 143
 144           <row><entry><varname>tap</varname></entry>
 145           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 146
 147           <row><entry><varname>tun</varname></entry>
 148           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 149
 150           <row><entry><varname>veth</varname></entry>
 151           <entry>An ethernet tunnel between a pair of network devices.</entry></row>
 152
 153           <row><entry><varname>vlan</varname></entry>
 154           <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>
 155
 156           <row><entry><varname>vti</varname></entry>
 157           <entry>An IPv4 over IPSec tunnel.</entry></row>
 158
 159           <row><entry><varname>vti6</varname></entry>
 160           <entry>An IPv6 over IPSec tunnel.</entry></row>
 161
 162           <row><entry><varname>vxlan</varname></entry>
 163           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 164         </tbody>
 165       </tgroup>
 166     </table>
 167
 168   </refsect1>
 169
 170   <refsect1>
 171     <title>[Match] Section Options</title>
 172
 173     <para>A virtual network device is only created if the
 174     <literal>[Match]</literal> section matches the current
 175     environment, or if the section is empty. The following keys are
 176     accepted:</para>
 177
 178     <variablelist class='network-directives'>
 179       <varlistentry>
 180         <term><varname>Host=</varname></term>
 181         <listitem>
 182           <para>Matches against the hostname or machine ID of the
 183           host. See <literal>ConditionHost=</literal> in
 184           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 185           for details.
 186           </para>
 187         </listitem>
 188       </varlistentry>
 189       <varlistentry>
 190         <term><varname>Virtualization=</varname></term>
 191         <listitem>
 192           <para>Checks whether the system is executed in a virtualized
 193           environment and optionally test whether it is a specific
 194           implementation. See
 195           <literal>ConditionVirtualization=</literal> in
 196           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 197           for details.
 198           </para>
 199         </listitem>
 200       </varlistentry>
 201       <varlistentry>
 202         <term><varname>KernelCommandLine=</varname></term>
 203         <listitem>
 204           <para>Checks whether a specific kernel command line option
 205           is set (or if prefixed with the exclamation mark unset). See
 206           <literal>ConditionKernelCommandLine=</literal> in
 207           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 208           for details.
 209           </para>
 210         </listitem>
 211       </varlistentry>
 212       <varlistentry>
 213         <term><varname>Architecture=</varname></term>
 214         <listitem>
 215           <para>Checks whether the system is running on a specific
 216           architecture. See <literal>ConditionArchitecture=</literal> in
 217           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 218           for details.
 219           </para>
 220         </listitem>
 221       </varlistentry>
 222     </variablelist>
 223
 224   </refsect1>
 225
 226   <refsect1>
 227     <title>[NetDev] Section Options</title>
 228
 229       <para>The <literal>[NetDev]</literal> section accepts the
 230       following keys:</para>
 231
 232       <variablelist class='network-directives'>
 233         <varlistentry>
 234           <term><varname>Description=</varname></term>
 235           <listitem>
 236             <para>A free-form description of the netdev.</para>
 237           </listitem>
 238         </varlistentry>
 239         <varlistentry>
 240           <term><varname>Name=</varname></term>
 241           <listitem>
 242             <para>The interface name used when creating the netdev.
 243             This option is compulsory.</para>
 244           </listitem>
 245         </varlistentry>
 246         <varlistentry>
 247           <term><varname>Kind=</varname></term>
 248           <listitem>
 249             <para>The netdev kind. This option is compulsory. See the
 250             <literal>Supported netdev kinds</literal> section for the
 251             valid keys.</para>
 252           </listitem>
 253         </varlistentry>
 254         <varlistentry>
 255           <term><varname>MTUBytes=</varname></term>
 256           <listitem>
 257             <para>The maximum transmission unit in bytes to set for
 258             the device. The usual suffixes K, M, G, are supported and
 259             are understood to the base of 1024. This key is not
 260             currently supported for <literal>tun</literal> or
 261             <literal>tap</literal> devices.
 262             </para>
 263           </listitem>
 264         </varlistentry>
 265         <varlistentry>
 266           <term><varname>MACAddress=</varname></term>
 267           <listitem>
 268             <para>The MAC address to use for the device. If none is
 269             given, one is generated based on the interface name and
 270             the
 271             <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 272             This key is not currently supported for
 273             <literal>tun</literal> or <literal>tap</literal> devices.
 274             </para>
 275           </listitem>
 276         </varlistentry>
 277       </variablelist>
 278   </refsect1>
 279
 280   <refsect1>
 281     <title>[VLAN] Section Options</title>
 282
 283       <para>The <literal>[VLAN]</literal> section only applies for
 284       netdevs of kind <literal>vlan</literal>, and accepts the
 285       following key:</para>
 286
 287       <variablelist class='network-directives'>
 288         <varlistentry>
 289           <term><varname>Id=</varname></term>
 290           <listitem>
 291             <para>The VLAN ID to use. An integer in the range 0–4094.
 292             This option is compulsory.</para>
 293           </listitem>
 294         </varlistentry>
 295       </variablelist>
 296
 297   </refsect1>
 298
 299   <refsect1>
 300     <title>[MACVLAN] Section Options</title>
 301
 302     <para>The <literal>[MACVLAN]</literal> section only applies for
 303     netdevs of kind <literal>macvlan</literal>, and accepts the
 304     following key:</para>
 305
 306     <variablelist class='network-directives'>
 307       <varlistentry>
 308         <term><varname>Mode=</varname></term>
 309         <listitem>
 310           <para>The MACVLAN mode to use. The supported options are
 311           <literal>private</literal>,
 312           <literal>vepa</literal>,
 313           <literal>bridge</literal>, and
 314           <literal>passthru</literal>.
 315           </para>
 316         </listitem>
 317       </varlistentry>
 318     </variablelist>
 319
 320   </refsect1>
 321
 322     <refsect1>
 323     <title>[MACVTAP] Section Options</title>
 324
 325     <para>The <literal>[MACVTAP]</literal> section applies for
 326     netdevs of kind <literal>macvtap</literal> and accepts the
 327     same key as <literal>[MACVLAN].</literal> </para>
 328
 329     </refsect1>
 330
 331   <refsect1>
 332     <title>[IPVLAN] Section Options</title>
 333
 334     <para>The <literal>[IPVLAN]</literal> section only applies for
 335     netdevs of kind <literal>ipvlan</literal>, and accepts the
 336     following key:</para>
 337
 338     <variablelist class='network-directives'>
 339       <varlistentry>
 340         <term><varname>Mode=</varname></term>
 341           <listitem>
 342             <para>The IPVLAN mode to use. The supported options are
 343             <literal>L2</literal> and <literal>L3</literal>.
 344             </para>
 345           </listitem>
 346       </varlistentry>
 347     </variablelist>
 348
 349   </refsect1>
 350
 351   <refsect1>
 352     <title>[VXLAN] Section Options</title>
 353     <para>The <literal>[VXLAN]</literal> section only applies for
 354     netdevs of kind <literal>vxlan</literal>, and accepts the
 355     following keys:</para>
 356
 357     <variablelist class='network-directives'>
 358       <varlistentry>
 359         <term><varname>Id=</varname></term>
 360         <listitem>
 361           <para>The VXLAN ID to use.</para>
 362         </listitem>
 363       </varlistentry>
 364       <varlistentry>
 365         <term><varname>Group=</varname></term>
 366         <listitem>
 367           <para>An assigned multicast group IP address.</para>
 368         </listitem>
 369       </varlistentry>
 370       <varlistentry>
 371         <term><varname>TOS=</varname></term>
 372         <listitem>
 373           <para>The Type Of Service byte value for a vxlan interface.</para>
 374         </listitem>
 375       </varlistentry>
 376       <varlistentry>
 377         <term><varname>TTL=</varname></term>
 378         <listitem>
 379           <para>A fixed Time To Live N on Virtual eXtensible Local
 380           Area Network packets. N is a number in the range 1-255. 0
 381           is a special value meaning that packets inherit the TTL
 382           value.</para>
 383         </listitem>
 384       </varlistentry>
 385       <varlistentry>
 386         <term><varname>MacLearning=</varname></term>
 387         <listitem>
 388           <para>A boolean. When true, enables dynamic MAC learning
 389           to discover remote MAC addresses.</para>
 390         </listitem>
 391       </varlistentry>
 392       <varlistentry>
 393         <term><varname>FDBAgeingSec=</varname></term>
 394         <listitem>
 395           <para>The lifetime of Forwarding Database entry learnt by
 396           the kernel in seconds.</para>
 397         </listitem>
 398       </varlistentry>
 399       <varlistentry>
 400         <term><varname>ARPProxy=</varname></term>
 401         <listitem>
 402           <para>A boolean. When true, enables ARP proxy.</para>
 403         </listitem>
 404       </varlistentry>
 405       <varlistentry>
 406         <term><varname>L2MissNotification=</varname></term>
 407         <listitem>
 408           <para>A boolean. When true, enables netlink LLADDR miss
 409           notifications.</para>
 410         </listitem>
 411       </varlistentry>
 412       <varlistentry>
 413         <term><varname>L3MissNotification=</varname></term>
 414         <listitem>
 415           <para>A boolean. When true, enables netlink IP ADDR miss
 416           notifications.</para>
 417         </listitem>
 418       </varlistentry>
 419       <varlistentry>
 420         <term><varname>RouteShortCircuit=</varname></term>
 421         <listitem>
 422           <para>A boolean. When true route short circuit is turned
 423           on.</para>
 424         </listitem>
 425       </varlistentry>
 426       <varlistentry>
 427         <term><varname>UDPCheckSum=</varname></term>
 428         <listitem>
 429           <para>A boolean. When true transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 430         </listitem>
 431       </varlistentry>
 432       <varlistentry>
 433         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 434         <listitem>
 435           <para>A boolean. When true sending zero checksums in VXLAN/IPv6 is turned on.</para>
 436         </listitem>
 437       </varlistentry>
 438       <varlistentry>
 439         <term><varname>UDP6ZeroCheckSumRx=</varname></term>
 440         <listitem>
 441           <para>A boolean. When true receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 442         </listitem>
 443       </varlistentry>
 444     <varlistentry>
 445       <term><varname>GroupPolicyExtension=</varname></term>
 446       <listitem>
 447         <para>A boolean. When true it enables Group Policy VXLAN extension security label mechanism
 448         across network peers based on VXLAN. For details about the Group Policy VXLAN see the
 449         <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 450         VXLAN Group Policy </ulink> document. Defaults to false.</para>
 451       </listitem>
 452     </varlistentry>
 453     </variablelist>
 454   </refsect1>
 455   <refsect1>
 456     <title>[Tunnel] Section Options</title>
 457
 458     <para>The <literal>[Tunnel]</literal> section only applies for
 459     netdevs of kind
 460     <literal>ipip</literal>,
 461     <literal>sit</literal>,
 462     <literal>gre</literal>,
 463     <literal>gretap</literal>,
 464     <literal>ip6gre</literal>,
 465     <literal>ip6gretap</literal>,
 466     <literal>vti</literal>,
 467     <literal>vti6</literal>, and
 468     <literal>ip6tnl</literal> and accepts
 469     the following keys:</para>
 470
 471     <variablelist class='network-directives'>
 472       <varlistentry>
 473         <term><varname>Local=</varname></term>
 474         <listitem>
 475           <para>A static local address for tunneled packets. It must
 476           be an address on another interface of this host.</para>
 477         </listitem>
 478       </varlistentry>
 479       <varlistentry>
 480         <term><varname>Remote=</varname></term>
 481         <listitem>
 482           <para>The remote endpoint of the tunnel.</para>
 483         </listitem>
 484       </varlistentry>
 485       <varlistentry>
 486         <term><varname>TOS=</varname></term>
 487         <listitem>
 488           <para>The Type Of Service byte value for a tunnel interface.
 489           For details about the TOS see the
 490           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
 491           Service in the Internet Protocol Suite </ulink> document.
 492           </para>
 493         </listitem>
 494       </varlistentry>
 495       <varlistentry>
 496         <term><varname>TTL=</varname></term>
 497         <listitem>
 498           <para>A fixed Time To Live N on tunneled packets. N is a
 499           number in the range 1-255. 0 is a special value meaning that
 500           packets inherit the TTL value. The default value for IPv4
 501           tunnels is: inherit. The default value for IPv6 tunnels is:
 502           64.</para>
 503         </listitem>
 504       </varlistentry>
 505       <varlistentry>
 506         <term><varname>DiscoverPathMTU=</varname></term>
 507         <listitem>
 508           <para>A boolean. When true, enables Path MTU Discovery on
 509           the tunnel.</para>
 510         </listitem>
 511       </varlistentry>
 512       <varlistentry>
 513         <term><varname>IPv6FlowLabel=</varname></term>
 514         <listitem>
 515           <para>Configures The 20-bit Flow Label (see <ulink url="https://tools.ietf.org/html/rfc6437">
 516           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
 517           RFC 2460</ulink>), is used by a node to label packets of a flow.
 518           It's only used for IPv6 Tunnels.
 519           A Flow Label of zero is used to indicate packets that have
 520           not been labeled. Takes following values.
 521           When <literal>inherit</literal> it uses the original flowlabel,
 522           or can be configured to any value between 0 to 0xFFFFF.</para>
 523         </listitem>
 524       </varlistentry>
 525       <varlistentry>
 526         <term><varname>CopyDSCP=</varname></term>
 527         <listitem>
 528           <para>A boolean. When true, the Differentiated Service Code
 529           Point (DSCP) field will be copied to the inner header from
 530           outer header during the decapsulation of an IPv6 tunnel
 531           packet. DSCP is a field in an IP packet that enables different
 532           levels of service to be assigned to network traffic.
 533           Defaults to <literal>no</literal>.
 534           </para>
 535         </listitem>
 536       </varlistentry>
 537       <varlistentry>
 538         <term><varname>EncapsulationLimit=</varname></term>
 539         <listitem>
 540           <para>The Tunnel Encapsulation Limit option specifies how many additional
 541           levels of encapsulation are permitted to be prepended to the packet.
 542           For example, a Tunnel Encapsulation Limit option containing a limit
 543           value of zero means that a packet carrying that option may not enter
 544           another tunnel before exiting the current tunnel.
 545           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
 546           The valid range is 0-255 and <literal>none</literal>. Defaults to 4.
 547         </para>
 548         </listitem>
 549       </varlistentry>
 550       <varlistentry>
 551         <term><varname>Mode=</varname></term>
 552         <listitem>
 553           <para>An <literal>ip6tnl</literal> tunnels can have three
 554           modes
 555           <literal>ip6ip6</literal> for IPv6 over IPv6,
 556           <literal>ipip6</literal> for IPv4 over IPv6 or
 557           <literal>any</literal> for either.
 558           </para>
 559         </listitem>
 560       </varlistentry>
 561     </variablelist>
 562   </refsect1>
 563   <refsect1>
 564     <title>[Peer] Section Options</title>
 565
 566       <para>The <literal>[Peer]</literal> section only applies for
 567       netdevs of kind <literal>veth</literal> and accepts the
 568       following key:</para>
 569
 570       <variablelist class='network-directives'>
 571         <varlistentry>
 572           <term><varname>Name=</varname></term>
 573           <listitem>
 574             <para>The interface name used when creating the netdev.
 575             This option is compulsory.</para>
 576           </listitem>
 577         </varlistentry>
 578         <varlistentry>
 579           <term><varname>MACAddress=</varname></term>
 580           <listitem>
 581             <para>The peer MACAddress, if not set it is generated in
 582             the same way as the MAC address of the main
 583             interface.</para>
 584           </listitem>
 585         </varlistentry>
 586       </variablelist>
 587   </refsect1>
 588   <refsect1>
 589     <title>[Tun] Section Options</title>
 590
 591     <para>The <literal>[Tun]</literal> section only applies for
 592     netdevs of kind <literal>tun</literal>, and accepts the following
 593     keys:</para>
 594
 595     <variablelist class='network-directives'>
 596       <varlistentry>
 597         <term><varname>OneQueue=</varname></term>
 598         <listitem><para>Takes a boolean argument. Configures whether
 599         all packets are queued at the device (enabled), or a fixed
 600         number of packets are queued at the device and the rest at the
 601         <literal>qdisc</literal>. Defaults to
 602         <literal>no</literal>.</para>
 603         </listitem>
 604       </varlistentry>
 605       <varlistentry>
 606         <term><varname>MultiQueue=</varname></term>
 607         <listitem><para>Takes a boolean argument. Configures whether
 608         to use multiple file descriptors (queues) to parallelize
 609         packets sending and receiving. Defaults to
 610         <literal>no</literal>.</para>
 611         </listitem>
 612       </varlistentry>
 613       <varlistentry>
 614         <term><varname>PacketInfo=</varname></term>
 615         <listitem><para>Takes a boolean argument. Configures whether
 616         packets should be prepended with four extra bytes (two flag
 617         bytes and two protocol bytes). If disabled it indicates that
 618         the packets will be pure IP packets. Defaults to
 619         <literal>no</literal>.</para>
 620         </listitem>
 621       </varlistentry>
 622       <varlistentry>
 623         <term><varname>VNetHeader=</varname></term>
 624         <listitem><para>Takes a boolean argument. Configures
 625         IFF_VNET_HDR flag for a tap device. It allows sending
 626         and receiving larger Generic Segmentation Offload (GSO)
 627         packets. This may increase throughput significantly.
 628         Defaults to
 629         <literal>no</literal>.</para>
 630         </listitem>
 631       </varlistentry>
 632       <varlistentry>
 633         <term><varname>User=</varname></term>
 634         <listitem><para>User to grant access to the
 635         <filename>/dev/net/tun</filename> device.</para>
 636         </listitem>
 637       </varlistentry>
 638       <varlistentry>
 639         <term><varname>Group=</varname></term>
 640         <listitem><para>Group to grant access to the
 641         <filename>/dev/net/tun</filename> device.</para>
 642         </listitem>
 643       </varlistentry>
 644
 645     </variablelist>
 646
 647   </refsect1>
 648
 649   <refsect1>
 650     <title>[Tap] Section Options</title>
 651
 652     <para>The <literal>[Tap]</literal> section only applies for
 653     netdevs of kind <literal>tap</literal>, and accepts the same keys
 654     as the <literal>[Tun]</literal> section.</para>
 655   </refsect1>
 656
 657   <refsect1>
 658     <title>[Bond] Section Options</title>
 659
 660     <para>The <literal>[Bond]</literal> section accepts the following
 661     key:</para>
 662
 663     <variablelist class='network-directives'>
 664       <varlistentry>
 665         <term><varname>Mode=</varname></term>
 666         <listitem>
 667           <para>Specifies one of the bonding policies. The default is
 668           <literal>balance-rr</literal> (round robin). Possible values are
 669           <literal>balance-rr</literal>,
 670           <literal>active-backup</literal>,
 671           <literal>balance-xor</literal>,
 672           <literal>broadcast</literal>,
 673           <literal>802.3ad</literal>,
 674           <literal>balance-tlb</literal>, and
 675           <literal>balance-alb</literal>.
 676           </para>
 677         </listitem>
 678       </varlistentry>
 679
 680       <varlistentry>
 681         <term><varname>TransmitHashPolicy=</varname></term>
 682         <listitem>
 683           <para>Selects the transmit hash policy to use for slave
 684           selection in balance-xor, 802.3ad, and tlb modes. Possible
 685           values are
 686           <literal>layer2</literal>,
 687           <literal>layer3+4</literal>,
 688           <literal>layer2+3</literal>,
 689           <literal>encap2+3</literal>,
 690           <literal>802.3ad</literal>, and
 691           <literal>encap3+4</literal>.
 692           </para>
 693         </listitem>
 694       </varlistentry>
 695
 696       <varlistentry>
 697         <term><varname>LACPTransmitRate=</varname></term>
 698         <listitem>
 699           <para>Specifies the rate with which link partner transmits
 700           Link Aggregation Control Protocol Data Unit packets in
 701           802.3ad mode. Possible values are <literal>slow</literal>,
 702           which requests partner to transmit LACPDUs every 30 seconds,
 703           and <literal>fast</literal>, which requests partner to
 704           transmit LACPDUs every second. The default value is
 705           <literal>slow</literal>.</para>
 706         </listitem>
 707       </varlistentry>
 708
 709       <varlistentry>
 710         <term><varname>MIIMonitorSec=</varname></term>
 711         <listitem>
 712           <para>Specifies the frequency that Media Independent
 713           Interface link monitoring will occur. A value of zero
 714           disables MII link monitoring. This value is rounded down to
 715           the nearest millisecond. The default value is 0.</para>
 716         </listitem>
 717       </varlistentry>
 718
 719       <varlistentry>
 720         <term><varname>UpDelaySec=</varname></term>
 721         <listitem>
 722           <para>Specifies the delay before a link is enabled after a
 723           link up status has been detected. This value is rounded down
 724           to a multiple of MIIMonitorSec. The default value is
 725           0.</para>
 726         </listitem>
 727       </varlistentry>
 728
 729       <varlistentry>
 730         <term><varname>DownDelaySec=</varname></term>
 731         <listitem>
 732           <para>Specifies the delay before a link is disabled after a
 733           link down status has been detected. This value is rounded
 734           down to a multiple of MIIMonitorSec. The default value is
 735           0.</para>
 736         </listitem>
 737       </varlistentry>
 738
 739       <varlistentry>
 740         <term><varname>LearnPacketIntervalSec=</varname></term>
 741         <listitem>
 742           <para>Specifies the number of seconds between instances where the bonding
 743           driver sends learning packets to each slaves peer switch.
 744           The valid range is 1 - 0x7fffffff; the default value is 1. This Option
 745           has effect only in balance-tlb and balance-alb modes.</para>
 746         </listitem>
 747       </varlistentry>
 748
 749       <varlistentry>
 750         <term><varname>AdSelect=</varname></term>
 751         <listitem>
 752           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
 753           <literal>stable</literal>,
 754           <literal>bandwidth</literal>,
 755           <literal>count</literal>
 756           </para>
 757         </listitem>
 758       </varlistentry>
 759
 760       <varlistentry>
 761         <term><varname>FailOverMACPolicy=</varname></term>
 762         <listitem>
 763           <para>Specifies whether active-backup mode should set all slaves to
 764           the same MAC address at enslavement or, when enabled, perform special handling of the
 765           bond's MAC address in accordance with the selected policy. The default policy is none.
 766           Possible values are
 767           <literal>none</literal>,
 768           <literal>active</literal>,
 769           <literal>follow</literal>
 770           </para>
 771         </listitem>
 772       </varlistentry>
 773
 774       <varlistentry>
 775         <term><varname>ARPValidate=</varname></term>
 776         <listitem>
 777           <para>Specifies whether or not ARP probes and replies should be
 778           validated in any mode that supports ARP monitoring, or whether
 779           non-ARP traffic should be filtered (disregarded) for link
 780           monitoring purposes. Possible values are
 781           <literal>none</literal>,
 782           <literal>active</literal>,
 783           <literal>backup</literal>,
 784           <literal>all</literal>
 785           </para>
 786         </listitem>
 787       </varlistentry>
 788
 789       <varlistentry>
 790         <term><varname>ARPIntervalSec=</varname></term>
 791         <listitem>
 792           <para>Specifies the ARP link monitoring frequency in milliseconds.
 793           A value of 0 disables ARP monitoring. The default value is 0.
 794           </para>
 795         </listitem>
 796       </varlistentry>
 797
 798       <varlistentry>
 799         <term><varname>ARPIPTargets=</varname></term>
 800         <listitem>
 801           <para>Specifies the IP addresses to use as ARP monitoring peers when
 802           ARPIntervalSec is greater than 0. These are the targets of the ARP request
 803           sent to determine the health of the link to the targets.
 804           Specify these values in ipv4 dotted decimal format. At least one IP
 805           address must be given for ARP monitoring to function. The
 806           maximum number of targets that can be specified is 16. The
 807           default value is no IP addresses.
 808           </para>
 809         </listitem>
 810       </varlistentry>
 811
 812       <varlistentry>
 813         <term><varname>ARPAllTargets=</varname></term>
 814         <listitem>
 815           <para>Specifies the quantity of ARPIPTargets that must be reachable
 816           in order for the ARP monitor to consider a slave as being up.
 817           This option affects only active-backup mode for slaves with
 818           ARPValidate enabled. Possible values are
 819           <literal>any</literal>,
 820           <literal>all</literal>
 821           </para>
 822         </listitem>
 823       </varlistentry>
 824
 825       <varlistentry>
 826         <term><varname>PrimaryReselectPolicy=</varname></term>
 827         <listitem>
 828           <para>Specifies the reselection policy for the primary slave.  This
 829           affects how the primary slave is chosen to become the active slave
 830           when failure of the active slave or recovery of the primary slave
 831           occurs. This option is designed to prevent flip-flopping between
 832           the primary slave and other slaves.  Possible values are
 833           <literal>always</literal>,
 834           <literal>better</literal>,
 835           <literal>failure</literal>
 836           </para>
 837         </listitem>
 838       </varlistentry>
 839
 840       <varlistentry>
 841         <term><varname>ResendIGMP=</varname></term>
 842         <listitem>
 843           <para>Specifies the number of IGMP membership reports to be issued after
 844           a failover event. One membership report is issued immediately after
 845           the failover, subsequent packets are sent in each 200ms interval.
 846           The valid range is (0 - 255). Defaults to 1. A value of 0
 847           prevents the IGMP membership report from being issued in response
 848           to the failover event.
 849           </para>
 850         </listitem>
 851       </varlistentry>
 852
 853       <varlistentry>
 854         <term><varname>PacketsPerSlave=</varname></term>
 855         <listitem>
 856           <para> Specify the number of packets to transmit through a slave before
 857             moving to the next one. When set to 0 then a slave is chosen at
 858             random. The valid range is (0 - 65535). Defaults to 1. This option
 859             has effect only in balance-rr mode.
 860           </para>
 861         </listitem>
 862       </varlistentry>
 863
 864       <varlistentry>
 865         <term><varname>GratuitousARP=</varname></term>
 866         <listitem>
 867           <para>Specify the number of peer notifications (gratuitous ARPs and
 868             unsolicited IPv6 Neighbor Advertisements) to be issued after a
 869             failover event.  As soon as the link is up on the new slave
 870             a peer notification is sent on the  bonding device and each
 871             VLAN sub-device.  This is repeated at each link monitor interval
 872             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
 873             greater than 1. The valid range is (0 - 255). Default value is 1.
 874             These options affect only the active-backup mode.
 875           </para>
 876         </listitem>
 877       </varlistentry>
 878
 879       <varlistentry>
 880         <term><varname>AllSlavesActive=</varname></term>
 881         <listitem>
 882           <para> A boolean. Specifies that duplicate frames (received on inactive ports)
 883           should be dropped false or delivered true. Normally, bonding will drop
 884           duplicate frames (received on inactive ports), which is desirable for
 885           most users. But there are some times it is nice to allow duplicate
 886           frames to be delivered. The default value is false (drop duplicate frames
 887           received on inactive ports).
 888           </para>
 889         </listitem>
 890       </varlistentry>
 891
 892       <varlistentry>
 893         <term><varname>MinLinks=</varname></term>
 894         <listitem>
 895           <para>Specifies the minimum number of links that must be active before
 896           asserting carrier. The default value is 0.
 897           </para>
 898         </listitem>
 899       </varlistentry>
 900
 901     </variablelist>
 902
 903     <para>For more detail information see
 904     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
 905     Linux Ethernet Bonding Driver HOWTO</ulink></para>
 906
 907   </refsect1>
 908
 909   <refsect1>
 910     <title>Example</title>
 911     <example>
 912       <title>/etc/systemd/network/bridge.netdev</title>
 913
 914       <programlisting>[NetDev]
 915 Name=bridge0
 916 Kind=bridge</programlisting>
 917     </example>
 918
 919     <example>
 920       <title>/etc/systemd/network/vlan1.netdev</title>
 921
 922       <programlisting>[Match]
 923 Virtualization=no
 924
 925 [NetDev]
 926 Name=vlan1
 927 Kind=vlan
 928
 929 [VLAN]
 930 Id=1</programlisting>
 931     </example>
 932     <example>
 933       <title>/etc/systemd/network/ipip.netdev</title>
 934       <programlisting>[NetDev]
 935 Name=ipip-tun
 936 Kind=ipip
 937 MTUBytes=1480
 938
 939 [Tunnel]
 940 Local=192.168.223.238
 941 Remote=192.169.224.239
 942 TTL=64</programlisting>
 943     </example>
 944     <example>
 945       <title>/etc/systemd/network/tap.netdev</title>
 946       <programlisting>[NetDev]
 947 Name=tap-test
 948 Kind=tap
 949
 950 [Tap]
 951 MultiQueue=true
 952 PacketInfo=true</programlisting> </example>
 953
 954     <example>
 955       <title>/etc/systemd/network/sit.netdev</title>
 956       <programlisting>[NetDev]
 957 Name=sit-tun
 958 Kind=sit
 959 MTUBytes=1480
 960
 961 [Tunnel]
 962 Local=10.65.223.238
 963 Remote=10.65.223.239</programlisting>
 964     </example>
 965
 966     <example>
 967       <title>/etc/systemd/network/gre.netdev</title>
 968       <programlisting>[NetDev]
 969 Name=gre-tun
 970 Kind=gre
 971 MTUBytes=1480
 972
 973 [Tunnel]
 974 Local=10.65.223.238
 975 Remote=10.65.223.239</programlisting>
 976     </example>
 977
 978     <example>
 979       <title>/etc/systemd/network/vti.netdev</title>
 980
 981       <programlisting>[NetDev]
 982 Name=vti-tun
 983 Kind=vti
 984 MTUBytes=1480
 985
 986 [Tunnel]
 987 Local=10.65.223.238
 988 Remote=10.65.223.239</programlisting>
 989     </example>
 990
 991     <example>
 992       <title>/etc/systemd/network/veth.netdev</title>
 993       <programlisting>[NetDev]
 994 Name=veth-test
 995 Kind=veth
 996
 997 [Peer]
 998 Name=veth-peer</programlisting>
 999     </example>
1000
1001     <example>
1002       <title>/etc/systemd/network/bond.netdev</title>
1003       <programlisting>[NetDev]
1004 Name=bond1
1005 Kind=bond
1006
1007 [Bond]
1008 Mode=802.3ad
1009 TransmitHashPolicy=layer3+4
1010 MIIMonitorSec=1s
1011 LACPTransmitRate=fast
1012 </programlisting>
1013     </example>
1014
1015     <example>
1016       <title>/etc/systemd/network/dummy.netdev</title>
1017       <programlisting>[NetDev]
1018 Name=dummy-test
1019 Kind=dummy
1020 MACAddress=12:34:56:78:9a:bc</programlisting>
1021     </example>
1022
1023   </refsect1>
1024   <refsect1>
1025     <title>See Also</title>
1026     <para>
1027       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1028       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1029       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1030       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1031     </para>
1032   </refsect1>
1033
1034 </refentry>