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