man/systemd.netdev.xml

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  10   Copyright 2013 Tom Gundersen
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  25
  26 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>
  27
  28   <refentryinfo>
  29     <title>systemd.network</title>
  30     <productname>systemd</productname>
  31
  32     <authorgroup>
  33       <author>
  34         <contrib>Developer</contrib>
  35         <firstname>Tom</firstname>
  36         <surname>Gundersen</surname>
  37         <email>teg@jklm.no</email>
  38       </author>
  39     </authorgroup>
  40   </refentryinfo>
  41
  42   <refmeta>
  43     <refentrytitle>systemd.netdev</refentrytitle>
  44     <manvolnum>5</manvolnum>
  45   </refmeta>
  46
  47   <refnamediv>
  48     <refname>systemd.netdev</refname>
  49     <refpurpose>Virtual Network Device configuration</refpurpose>
  50   </refnamediv>
  51
  52   <refsynopsisdiv>
  53     <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  54   </refsynopsisdiv>
  55
  56   <refsect1>
  57     <title>Description</title>
  58
  59     <para>Network setup is performed by
  60     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  61     </para>
  62
  63     <para>The main Virtual Network Device file must have the extension <filename>.netdev</filename>;
  64     other extensions are ignored. Virtual network devices are created as soon as networkd is
  65     started. If a netdev with the specified name already exists, networkd will use that as-is rather
  66     than create its own. Note that 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 files located in the system
  70     network directory <filename>/usr/lib/systemd/network</filename>, the volatile runtime network
  71     directory <filename>/run/systemd/network</filename> and the local administration network
  72     directory <filename>/etc/systemd/network</filename>. All configuration files are collectively
  73     sorted and processed in lexical order, regardless of the directories in which they live.
  74     However, files with identical filenames replace each other. Files in <filename>/etc</filename>
  75     have the highest priority, files in <filename>/run</filename> take precedence over files with
  76     the same name in <filename>/usr/lib</filename>. This can be used to override a system-supplied
  77     configuration file with a local file if needed. As a special case, an empty file (file size 0)
  78     or symlink with the same name pointing to <filename>/dev/null</filename> disables the
  79     configuration file entirely (it is "masked").</para>
  80
  81     <para>Along with the netdev file <filename>foo.netdev</filename>, a "drop-in" directory
  82     <filename>foo.netdev.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  83     from this directory will be parsed after the file itself is parsed. This is useful to alter or
  84     add configuration settings, without having to modify the main configuration file. Each drop-in
  85     file must have appropriate section headers.</para>
  86
  87     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  88     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  89     <filename>/run/systemd/network</filename> directories. Drop-in files in
  90     <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
  91     take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
  92     directories take precedence over the main netdev file wherever located. (Of course, since
  93     <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is
  94     unlikely drop-ins should be used in either of those places.)</para>
  95   </refsect1>
  96
  97   <refsect1>
  98     <title>Supported netdev kinds</title>
  99
 100     <para>The following kinds of virtual network devices may be
 101     configured in <filename>.netdev</filename> files:</para>
 102
 103     <table>
 104       <title>Supported kinds of virtual network devices</title>
 105
 106       <tgroup cols='2'>
 107         <colspec colname='kind' />
 108         <colspec colname='explanation' />
 109         <thead><row>
 110           <entry>Kind</entry>
 111           <entry>Description</entry>
 112         </row></thead>
 113         <tbody>
 114           <row><entry><varname>bond</varname></entry>
 115           <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>
 116
 117           <row><entry><varname>bridge</varname></entry>
 118           <entry>A bridge device is a software switch, and each of its slave devices and the bridge itself are ports of the switch.</entry></row>
 119
 120           <row><entry><varname>dummy</varname></entry>
 121           <entry>A dummy device drops all packets sent to it.</entry></row>
 122
 123           <row><entry><varname>gre</varname></entry>
 124           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
 125
 126           <row><entry><varname>gretap</varname></entry>
 127           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 128
 129           <row><entry><varname>ip6gre</varname></entry>
 130           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 131
 132           <row><entry><varname>ip6tnl</varname></entry>
 133           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 134
 135           <row><entry><varname>ip6gretap</varname></entry>
 136           <entry>A Level 2 GRE tunnel over IPv6.</entry></row>
 137
 138           <row><entry><varname>ipip</varname></entry>
 139           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 140
 141           <row><entry><varname>ipvlan</varname></entry>
 142           <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 143
 144           <row><entry><varname>macvlan</varname></entry>
 145           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 146
 147           <row><entry><varname>macvtap</varname></entry>
 148           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 149
 150           <row><entry><varname>sit</varname></entry>
 151           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 152
 153           <row><entry><varname>tap</varname></entry>
 154           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 155
 156           <row><entry><varname>tun</varname></entry>
 157           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 158
 159           <row><entry><varname>veth</varname></entry>
 160           <entry>An Ethernet tunnel between a pair of network devices.</entry></row>
 161
 162           <row><entry><varname>vlan</varname></entry>
 163           <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>
 164
 165           <row><entry><varname>vti</varname></entry>
 166           <entry>An IPv4 over IPSec tunnel.</entry></row>
 167
 168           <row><entry><varname>vti6</varname></entry>
 169           <entry>An IPv6 over IPSec tunnel.</entry></row>
 170
 171           <row><entry><varname>vxlan</varname></entry>
 172           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 173
 174           <row><entry><varname>geneve</varname></entry>
 175           <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.</entry></row>
 176
 177           <row><entry><varname>vrf</varname></entry>
 178           <entry>A Virtual Routing and Forwarding (<ulink url="https://www.kernel.org/doc/Documentation/networking/vrf.txt">VRF</ulink>) interface to create separate routing and forwarding domains.</entry></row>
 179
 180           <row><entry><varname>vcan</varname></entry>
 181           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 182
 183           <row><entry><varname>vxcan</varname></entry>
 184           <entry>The virtual CAN tunnel driver (vxcan). Similar to the virtual ethernet driver veth, vxcan implements a local CAN traffic tunnel between two virtual CAN network devices. When creating a vxcan, two vxcan devices are created as pair. When one end receives the packet it appears on its pair and vice versa. The vxcan can be used for cross namespace communication.
 185           </entry></row>
 186
 187         </tbody>
 188       </tgroup>
 189     </table>
 190
 191   </refsect1>
 192
 193   <refsect1>
 194     <title>[Match] Section Options</title>
 195
 196     <para>A virtual network device is only created if the
 197     <literal>[Match]</literal> section matches the current
 198     environment, or if the section is empty. The following keys are
 199     accepted:</para>
 200
 201     <variablelist class='network-directives'>
 202       <varlistentry>
 203         <term><varname>Host=</varname></term>
 204         <listitem>
 205           <para>Matches against the hostname or machine ID of the
 206           host. See <literal>ConditionHost=</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>Virtualization=</varname></term>
 214         <listitem>
 215           <para>Checks whether the system is executed in a virtualized
 216           environment and optionally test whether it is a specific
 217           implementation. See
 218           <literal>ConditionVirtualization=</literal> in
 219           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 220           for details.
 221           </para>
 222         </listitem>
 223       </varlistentry>
 224       <varlistentry>
 225         <term><varname>KernelCommandLine=</varname></term>
 226         <listitem>
 227           <para>Checks whether a specific kernel command line option
 228           is set (or if prefixed with the exclamation mark unset). See
 229           <literal>ConditionKernelCommandLine=</literal> in
 230           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 231           for details.
 232           </para>
 233         </listitem>
 234       </varlistentry>
 235       <varlistentry>
 236         <term><varname>KernelVersion=</varname></term>
 237         <listitem>
 238           <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a certain
 239           expression (or if prefixed with the exclamation mark does not match it). See
 240           <literal>ConditionKernelVersion=</literal> in
 241           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
 242           </para>
 243         </listitem>
 244       </varlistentry>
 245       <varlistentry>
 246         <term><varname>Architecture=</varname></term>
 247         <listitem>
 248           <para>Checks whether the system is running on a specific
 249           architecture. See <literal>ConditionArchitecture=</literal> in
 250           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 251           for details.
 252           </para>
 253         </listitem>
 254       </varlistentry>
 255     </variablelist>
 256
 257   </refsect1>
 258
 259   <refsect1>
 260     <title>[NetDev] Section Options</title>
 261
 262       <para>The <literal>[NetDev]</literal> section accepts the
 263       following keys:</para>
 264
 265       <variablelist class='network-directives'>
 266         <varlistentry>
 267           <term><varname>Description=</varname></term>
 268           <listitem>
 269             <para>A free-form description of the netdev.</para>
 270           </listitem>
 271         </varlistentry>
 272         <varlistentry>
 273           <term><varname>Name=</varname></term>
 274           <listitem>
 275             <para>The interface name used when creating the netdev.
 276             This option is compulsory.</para>
 277           </listitem>
 278         </varlistentry>
 279         <varlistentry>
 280           <term><varname>Kind=</varname></term>
 281           <listitem>
 282             <para>The netdev kind. This option is compulsory. See the
 283             <literal>Supported netdev kinds</literal> section for the
 284             valid keys.</para>
 285           </listitem>
 286         </varlistentry>
 287         <varlistentry>
 288           <term><varname>MTUBytes=</varname></term>
 289           <listitem>
 290             <para>The maximum transmission unit in bytes to set for
 291             the device. The usual suffixes K, M, G, are supported and
 292             are understood to the base of 1024. This key is not
 293             currently supported for <literal>tun</literal> or
 294             <literal>tap</literal> devices.
 295             </para>
 296           </listitem>
 297         </varlistentry>
 298         <varlistentry>
 299           <term><varname>MACAddress=</varname></term>
 300           <listitem>
 301             <para>The MAC address to use for the device. If none is
 302             given, one is generated based on the interface name and
 303             the
 304             <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 305             This key is not currently supported for
 306             <literal>tun</literal> or <literal>tap</literal> devices.
 307             </para>
 308           </listitem>
 309         </varlistentry>
 310       </variablelist>
 311   </refsect1>
 312
 313     <refsect1>
 314     <title>[Bridge] Section Options</title>
 315
 316       <para>The <literal>[Bridge]</literal> section only applies for
 317       netdevs of kind <literal>bridge</literal>, and accepts the
 318       following keys:</para>
 319
 320       <variablelist class='network-directives'>
 321         <varlistentry>
 322           <term><varname>HelloTimeSec=</varname></term>
 323           <listitem>
 324             <para>HelloTimeSec specifies the number of seconds between two hello packets
 325             sent out by the root bridge and the designated bridges. Hello packets are
 326             used to communicate information about the topology throughout the entire
 327             bridged local area network.</para>
 328           </listitem>
 329         </varlistentry>
 330         <varlistentry>
 331           <term><varname>MaxAgeSec=</varname></term>
 332           <listitem>
 333             <para>MaxAgeSec specifies the number of seconds of maximum message age.
 334             If the last seen (received) hello packet is more than this number of
 335             seconds old, the bridge in question will start the takeover procedure
 336             in attempt to become the Root Bridge itself.</para>
 337           </listitem>
 338         </varlistentry>
 339         <varlistentry>
 340           <term><varname>ForwardDelaySec=</varname></term>
 341           <listitem>
 342             <para>ForwardDelaySec specifies the number of seconds spent in each
 343             of the Listening and Learning states before the Forwarding state is entered.</para>
 344           </listitem>
 345         </varlistentry>
 346         <varlistentry>
 347           <term><varname>AgeingTimeSec=</varname></term>
 348           <listitem>
 349             <para>This specifies the number of seconds a MAC Address will be kept in
 350             the forwarding database after having a packet received from this MAC Address.</para>
 351           </listitem>
 352         </varlistentry>
 353         <varlistentry>
 354           <term><varname>Priority=</varname></term>
 355           <listitem>
 356             <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 357             means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 358           </listitem>
 359         </varlistentry>
 360         <varlistentry>
 361           <term><varname>GroupForwardMask=</varname></term>
 362           <listitem>
 363             <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 364             local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 365             is performed between the specified bitmask and the exponentiation of 2^X, the
 366             lower nibble of the last octet of the MAC address. For example, a value of 8
 367             would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 368           </listitem>
 369         </varlistentry>
 370         <varlistentry>
 371           <term><varname>DefaultPVID=</varname></term>
 372           <listitem>
 373             <para>This specifies the default port VLAN ID of a newly attached bridge port.
 374             Set this to an integer in the range 1–4094 or <literal>none</literal> to disable the PVID.</para>
 375           </listitem>
 376         </varlistentry>
 377         <varlistentry>
 378           <term><varname>MulticastQuerier=</varname></term>
 379           <listitem>
 380             <para>A boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 381             If enabled, the kernel will send general ICMP queries from a zero source address.
 382             This feature should allow faster convergence on startup, but it causes some
 383             multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 384             When unset, the kernel's default setting applies.
 385             </para>
 386           </listitem>
 387         </varlistentry>
 388         <varlistentry>
 389           <term><varname>MulticastSnooping=</varname></term>
 390           <listitem>
 391             <para>A boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
 392             If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
 393             between hosts and multicast routers. When unset, the kernel's default setting applies.
 394             </para>
 395           </listitem>
 396         </varlistentry>
 397         <varlistentry>
 398           <term><varname>VLANFiltering=</varname></term>
 399           <listitem>
 400             <para>A boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 401             If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's
 402             default setting applies.
 403             </para>
 404           </listitem>
 405         </varlistentry>
 406           <varlistentry>
 407           <term><varname>STP=</varname></term>
 408           <listitem>
 409             <para>A boolean. This enables the bridge's Spanning Tree Protocol (STP). When unset,
 410             the kernel's default setting applies.
 411             </para>
 412           </listitem>
 413         </varlistentry>
 414       </variablelist>
 415   </refsect1>
 416
 417   <refsect1>
 418     <title>[VLAN] Section Options</title>
 419
 420       <para>The <literal>[VLAN]</literal> section only applies for
 421       netdevs of kind <literal>vlan</literal>, and accepts the
 422       following key:</para>
 423
 424       <variablelist class='network-directives'>
 425         <varlistentry>
 426           <term><varname>Id=</varname></term>
 427           <listitem>
 428             <para>The VLAN ID to use. An integer in the range 0–4094.
 429             This option is compulsory.</para>
 430           </listitem>
 431         </varlistentry>
 432         <varlistentry>
 433           <term><varname>GVRP=</varname></term>
 434           <listitem>
 435             <para>The Generic VLAN Registration Protocol (GVRP) is a protocol that
 436             allows automatic learning of VLANs on a network. A boolean. When unset,
 437             the kernel's default setting applies.</para>
 438           </listitem>
 439         </varlistentry>
 440         <varlistentry>
 441           <term><varname>MVRP=</varname></term>
 442           <listitem>
 443             <para>Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 444             Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 445             for automatic configuration of VLAN information on switches. It was defined
 446             in the 802.1ak amendment to 802.1Q-2005. A boolean. When unset, the kernel's
 447             default setting applies.</para>
 448           </listitem>
 449         </varlistentry>
 450         <varlistentry>
 451           <term><varname>LooseBinding=</varname></term>
 452           <listitem>
 453             <para>The VLAN loose binding mode, in which only the operational state is passed
 454             from the parent to the associated VLANs, but the VLAN device state is not changed.
 455             A boolean. When unset, the kernel's default setting applies.</para>
 456           </listitem>
 457         </varlistentry>
 458         <varlistentry>
 459           <term><varname>ReorderHeader=</varname></term>
 460           <listitem>
 461             <para>The VLAN reorder header is set VLAN interfaces behave like physical interfaces.
 462             A boolean. When unset, the kernel's default setting applies.</para>
 463           </listitem>
 464         </varlistentry>
 465       </variablelist>
 466   </refsect1>
 467
 468   <refsect1>
 469     <title>[MACVLAN] Section Options</title>
 470
 471     <para>The <literal>[MACVLAN]</literal> section only applies for
 472     netdevs of kind <literal>macvlan</literal>, and accepts the
 473     following key:</para>
 474
 475     <variablelist class='network-directives'>
 476       <varlistentry>
 477         <term><varname>Mode=</varname></term>
 478         <listitem>
 479           <para>The MACVLAN mode to use. The supported options are
 480           <literal>private</literal>,
 481           <literal>vepa</literal>,
 482           <literal>bridge</literal>, and
 483           <literal>passthru</literal>.
 484           </para>
 485         </listitem>
 486       </varlistentry>
 487     </variablelist>
 488
 489   </refsect1>
 490
 491     <refsect1>
 492     <title>[MACVTAP] Section Options</title>
 493
 494     <para>The <literal>[MACVTAP]</literal> section applies for
 495     netdevs of kind <literal>macvtap</literal> and accepts the
 496     same key as <literal>[MACVLAN]</literal>.</para>
 497
 498     </refsect1>
 499
 500   <refsect1>
 501     <title>[IPVLAN] Section Options</title>
 502
 503     <para>The <literal>[IPVLAN]</literal> section only applies for
 504     netdevs of kind <literal>ipvlan</literal>, and accepts the
 505     following key:</para>
 506
 507     <variablelist class='network-directives'>
 508       <varlistentry>
 509         <term><varname>Mode=</varname></term>
 510           <listitem>
 511             <para>The IPVLAN mode to use. The supported options are
 512             <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 513             </para>
 514           </listitem>
 515       </varlistentry>
 516        <varlistentry>
 517         <term><varname>Flags=</varname></term>
 518           <listitem>
 519             <para>The IPVLAN flags to use. The supported options are
 520             <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 521             </para>
 522           </listitem>
 523       </varlistentry>
 524     </variablelist>
 525
 526   </refsect1>
 527
 528   <refsect1>
 529     <title>[VXLAN] Section Options</title>
 530     <para>The <literal>[VXLAN]</literal> section only applies for
 531     netdevs of kind <literal>vxlan</literal>, and accepts the
 532     following keys:</para>
 533
 534     <variablelist class='network-directives'>
 535       <varlistentry>
 536         <term><varname>Id=</varname></term>
 537         <listitem>
 538           <para>The VXLAN ID to use.</para>
 539         </listitem>
 540       </varlistentry>
 541       <varlistentry>
 542         <term><varname>Remote=</varname></term>
 543         <listitem>
 544           <para>Configures destination multicast group IP address.</para>
 545         </listitem>
 546       </varlistentry>
 547       <varlistentry>
 548         <term><varname>Local=</varname></term>
 549         <listitem>
 550           <para>Configures local IP address.</para>
 551         </listitem>
 552       </varlistentry>
 553         <varlistentry>
 554         <term><varname>TOS=</varname></term>
 555         <listitem>
 556           <para>The Type Of Service byte value for a vxlan interface.</para>
 557         </listitem>
 558       </varlistentry>
 559       <varlistentry>
 560         <term><varname>TTL=</varname></term>
 561         <listitem>
 562           <para>A fixed Time To Live N on Virtual eXtensible Local
 563           Area Network packets. N is a number in the range 1–255. 0
 564           is a special value meaning that packets inherit the TTL
 565           value.</para>
 566         </listitem>
 567       </varlistentry>
 568       <varlistentry>
 569         <term><varname>MacLearning=</varname></term>
 570         <listitem>
 571           <para>A boolean. When true, enables dynamic MAC learning
 572           to discover remote MAC addresses.</para>
 573         </listitem>
 574       </varlistentry>
 575       <varlistentry>
 576         <term><varname>FDBAgeingSec=</varname></term>
 577         <listitem>
 578           <para>The lifetime of Forwarding Database entry learnt by
 579           the kernel, in seconds.</para>
 580         </listitem>
 581       </varlistentry>
 582       <varlistentry>
 583         <term><varname>MaximumFDBEntries=</varname></term>
 584         <listitem>
 585           <para>Configures maximum number of FDB entries.</para>
 586         </listitem>
 587       </varlistentry>
 588       <varlistentry>
 589         <term><varname>ReduceARPProxy=</varname></term>
 590         <listitem>
 591           <para>A boolean. When true, bridge-connected VXLAN tunnel
 592           endpoint answers ARP requests from the local bridge on behalf
 593           of remote Distributed Overlay Virtual Ethernet
 594           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 595           (DVOE)</ulink> clients. Defaults to false.</para>
 596         </listitem>
 597       </varlistentry>
 598       <varlistentry>
 599         <term><varname>L2MissNotification=</varname></term>
 600         <listitem>
 601           <para>A boolean. When true, enables netlink LLADDR miss
 602           notifications.</para>
 603         </listitem>
 604       </varlistentry>
 605       <varlistentry>
 606         <term><varname>L3MissNotification=</varname></term>
 607         <listitem>
 608           <para>A boolean. When true, enables netlink IP address miss
 609           notifications.</para>
 610         </listitem>
 611       </varlistentry>
 612       <varlistentry>
 613         <term><varname>RouteShortCircuit=</varname></term>
 614         <listitem>
 615           <para>A boolean. When true, route short circuiting is turned
 616           on.</para>
 617         </listitem>
 618       </varlistentry>
 619       <varlistentry>
 620         <term><varname>UDPChecksum=</varname></term>
 621         <listitem>
 622           <para>A boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 623         </listitem>
 624       </varlistentry>
 625       <varlistentry>
 626         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 627         <listitem>
 628           <para>A boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 629         </listitem>
 630       </varlistentry>
 631       <varlistentry>
 632         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 633         <listitem>
 634           <para>A boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 635         </listitem>
 636       </varlistentry>
 637       <varlistentry>
 638         <term><varname>RemoteChecksumTx=</varname></term>
 639         <listitem>
 640           <para>A boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 641         </listitem>
 642       </varlistentry>
 643       <varlistentry>
 644         <term><varname>RemoteChecksumRx=</varname></term>
 645         <listitem>
 646           <para>A boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 647         </listitem>
 648       </varlistentry>
 649     <varlistentry>
 650       <term><varname>GroupPolicyExtension=</varname></term>
 651       <listitem>
 652         <para>A boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 653         across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 654         <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 655         VXLAN Group Policy </ulink> document. Defaults to false.</para>
 656       </listitem>
 657     </varlistentry>
 658     <varlistentry>
 659       <term><varname>DestinationPort=</varname></term>
 660       <listitem>
 661         <para>Configures the default destination UDP port on a per-device basis.
 662         If destination port is not specified then Linux kernel default will be used.
 663         Set destination port 4789 to get the IANA assigned value. If not set or if the
 664         destination port is assigned the empty string the default port of 4789 is used.</para>
 665       </listitem>
 666     </varlistentry>
 667     <varlistentry>
 668       <term><varname>PortRange=</varname></term>
 669         <listitem>
 670           <para>Configures VXLAN port range. VXLAN bases source
 671           UDP port based on flow to help the receiver to be able
 672           to load balance based on outer header flow. It
 673           restricts the port range to the normal UDP local
 674           ports, and allows overriding via configuration.</para>
 675         </listitem>
 676       </varlistentry>
 677     <varlistentry>
 678       <term><varname>FlowLabel=</varname></term>
 679         <listitem>
 680           <para>Specifies the flow label to use in outgoing packets.
 681           The valid range is 0-1048575.
 682           </para>
 683         </listitem>
 684       </varlistentry>
 685     </variablelist>
 686   </refsect1>
 687   <refsect1>
 688     <title>[GENEVE] Section Options</title>
 689     <para>The <literal>[GENEVE]</literal> section only applies for
 690     netdevs of kind <literal>geneve</literal>, and accepts the
 691     following keys:</para>
 692
 693     <variablelist class='network-directives'>
 694       <varlistentry>
 695         <term><varname>Id=</varname></term>
 696         <listitem>
 697           <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [0-16777215].</para>
 698         </listitem>
 699       </varlistentry>
 700       <varlistentry>
 701         <term><varname>Remote=</varname></term>
 702         <listitem>
 703           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 704         </listitem>
 705       </varlistentry>
 706       <varlistentry>
 707         <term><varname>TOS=</varname></term>
 708         <listitem>
 709           <para>Specifies the TOS value to use in outgoing packets. Ranges [1-255].</para>
 710         </listitem>
 711       </varlistentry>
 712       <varlistentry>
 713         <term><varname>TTL=</varname></term>
 714         <listitem>
 715           <para>Specifies the TTL value to use in outgoing packets. Ranges [1-255].</para>
 716         </listitem>
 717       </varlistentry>
 718       <varlistentry>
 719         <term><varname>UDPChecksum=</varname></term>
 720         <listitem>
 721           <para>A boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.</para>
 722         </listitem>
 723       </varlistentry>
 724       <varlistentry>
 725         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 726         <listitem>
 727           <para>A boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 728         </listitem>
 729       </varlistentry>
 730       <varlistentry>
 731         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 732         <listitem>
 733           <para>A boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 734         </listitem>
 735       </varlistentry>
 736     <varlistentry>
 737       <term><varname>DestinationPort=</varname></term>
 738       <listitem>
 739         <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 740         port of 6081 is used.</para>
 741       </listitem>
 742     </varlistentry>
 743     <varlistentry>
 744       <term><varname>FlowLabel=</varname></term>
 745         <listitem>
 746           <para>Specifies the flow label to use in outgoing packets.</para>
 747         </listitem>
 748       </varlistentry>
 749     </variablelist>
 750   </refsect1>
 751   <refsect1>
 752     <title>[Tunnel] Section Options</title>
 753
 754     <para>The <literal>[Tunnel]</literal> section only applies for
 755     netdevs of kind
 756     <literal>ipip</literal>,
 757     <literal>sit</literal>,
 758     <literal>gre</literal>,
 759     <literal>gretap</literal>,
 760     <literal>ip6gre</literal>,
 761     <literal>ip6gretap</literal>,
 762     <literal>vti</literal>,
 763     <literal>vti6</literal>, and
 764     <literal>ip6tnl</literal> and accepts
 765     the following keys:</para>
 766
 767     <variablelist class='network-directives'>
 768       <varlistentry>
 769         <term><varname>Local=</varname></term>
 770         <listitem>
 771           <para>A static local address for tunneled packets. It must
 772           be an address on another interface of this host.</para>
 773         </listitem>
 774       </varlistentry>
 775       <varlistentry>
 776         <term><varname>Remote=</varname></term>
 777         <listitem>
 778           <para>The remote endpoint of the tunnel.</para>
 779         </listitem>
 780       </varlistentry>
 781       <varlistentry>
 782         <term><varname>TOS=</varname></term>
 783         <listitem>
 784           <para>The Type Of Service byte value for a tunnel interface.
 785           For details about the TOS, see the
 786           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
 787           Service in the Internet Protocol Suite </ulink> document.
 788           </para>
 789         </listitem>
 790       </varlistentry>
 791       <varlistentry>
 792         <term><varname>TTL=</varname></term>
 793         <listitem>
 794           <para>A fixed Time To Live N on tunneled packets. N is a
 795           number in the range 1–255. 0 is a special value meaning that
 796           packets inherit the TTL value. The default value for IPv4
 797           tunnels is: inherit. The default value for IPv6 tunnels is
 798           64.</para>
 799         </listitem>
 800       </varlistentry>
 801       <varlistentry>
 802         <term><varname>DiscoverPathMTU=</varname></term>
 803         <listitem>
 804           <para>A boolean. When true, enables Path MTU Discovery on
 805           the tunnel.</para>
 806         </listitem>
 807       </varlistentry>
 808       <varlistentry>
 809         <term><varname>IPv6FlowLabel=</varname></term>
 810         <listitem>
 811           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
 812           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
 813           RFC 2460</ulink>), which is used by a node to label packets of a flow.
 814           It is only used for IPv6 tunnels.
 815           A flow label of zero is used to indicate packets that have
 816           not been labeled.
 817           It can be configured to a value in the range 0–0xFFFFF, or be
 818           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
 819         </listitem>
 820       </varlistentry>
 821       <varlistentry>
 822         <term><varname>CopyDSCP=</varname></term>
 823         <listitem>
 824           <para>A boolean. When true, the Differentiated Service Code
 825           Point (DSCP) field will be copied to the inner header from
 826           outer header during the decapsulation of an IPv6 tunnel
 827           packet. DSCP is a field in an IP packet that enables different
 828           levels of service to be assigned to network traffic.
 829           Defaults to <literal>no</literal>.
 830           </para>
 831         </listitem>
 832       </varlistentry>
 833       <varlistentry>
 834         <term><varname>EncapsulationLimit=</varname></term>
 835         <listitem>
 836           <para>The Tunnel Encapsulation Limit option specifies how many additional
 837           levels of encapsulation are permitted to be prepended to the packet.
 838           For example, a Tunnel Encapsulation Limit option containing a limit
 839           value of zero means that a packet carrying that option may not enter
 840           another tunnel before exiting the current tunnel.
 841           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
 842           The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
 843         </para>
 844         </listitem>
 845       </varlistentry>
 846       <varlistentry>
 847         <term><varname>Key=</varname></term>
 848         <listitem>
 849           <para>The <varname>Key=</varname> parameter specifies the same key to use in
 850           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
 851           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
 852           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
 853           and control path) in ip xfrm (framework used to implement IPsec protocol).
 854           See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
 855           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6
 856           tunnels.</para>
 857         </listitem>
 858       </varlistentry>
 859       <varlistentry>
 860         <term><varname>InputKey=</varname></term>
 861         <listitem>
 862           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
 863           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
 864         </listitem>
 865       </varlistentry>
 866       <varlistentry>
 867         <term><varname>OutputKey=</varname></term>
 868         <listitem>
 869           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
 870           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
 871         </listitem>
 872       </varlistentry>
 873       <varlistentry>
 874         <term><varname>Mode=</varname></term>
 875         <listitem>
 876           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
 877           modes
 878           <literal>ip6ip6</literal> for IPv6 over IPv6,
 879           <literal>ipip6</literal> for IPv4 over IPv6 or
 880           <literal>any</literal> for either.
 881           </para>
 882         </listitem>
 883       </varlistentry>
 884       <varlistentry>
 885         <term><varname>Independent=</varname></term>
 886         <listitem>
 887           <para>A boolean. When true tunnel does not require .network file. Created as "tunnel@NONE".
 888           Defaults to <literal>false</literal>.
 889           </para>
 890         </listitem>
 891       </varlistentry>
 892     </variablelist>
 893   </refsect1>
 894   <refsect1>
 895     <title>[Peer] Section Options</title>
 896
 897       <para>The <literal>[Peer]</literal> section only applies for
 898       netdevs of kind <literal>veth</literal> and accepts the
 899       following keys:</para>
 900
 901       <variablelist class='network-directives'>
 902         <varlistentry>
 903           <term><varname>Name=</varname></term>
 904           <listitem>
 905             <para>The interface name used when creating the netdev.
 906             This option is compulsory.</para>
 907           </listitem>
 908         </varlistentry>
 909         <varlistentry>
 910           <term><varname>MACAddress=</varname></term>
 911           <listitem>
 912             <para>The peer MACAddress, if not set, it is generated in
 913             the same way as the MAC address of the main
 914             interface.</para>
 915           </listitem>
 916         </varlistentry>
 917       </variablelist>
 918   </refsect1>
 919   <refsect1>
 920   <title>[VXCAN] Section Options</title>
 921       <para>The <literal>[VXCAN]</literal> section only applies for
 922       netdevs of kind <literal>vxcan</literal> and accepts the
 923       following key:</para>
 924
 925       <variablelist class='network-directives'>
 926         <varlistentry>
 927           <term><varname>Peer=</varname></term>
 928           <listitem>
 929             <para>The peer interface name used when creating the netdev.
 930             This option is compulsory.</para>
 931           </listitem>
 932         </varlistentry>
 933       </variablelist>
 934   </refsect1>
 935   <refsect1>
 936     <title>[Tun] Section Options</title>
 937
 938     <para>The <literal>[Tun]</literal> section only applies for
 939     netdevs of kind <literal>tun</literal>, and accepts the following
 940     keys:</para>
 941
 942     <variablelist class='network-directives'>
 943       <varlistentry>
 944         <term><varname>OneQueue=</varname></term>
 945         <listitem><para>Takes a boolean argument. Configures whether
 946         all packets are queued at the device (enabled), or a fixed
 947         number of packets are queued at the device and the rest at the
 948         <literal>qdisc</literal>. Defaults to
 949         <literal>no</literal>.</para>
 950         </listitem>
 951       </varlistentry>
 952       <varlistentry>
 953         <term><varname>MultiQueue=</varname></term>
 954         <listitem><para>Takes a boolean argument. Configures whether
 955         to use multiple file descriptors (queues) to parallelize
 956         packets sending and receiving. Defaults to
 957         <literal>no</literal>.</para>
 958         </listitem>
 959       </varlistentry>
 960       <varlistentry>
 961         <term><varname>PacketInfo=</varname></term>
 962         <listitem><para>Takes a boolean argument. Configures whether
 963         packets should be prepended with four extra bytes (two flag
 964         bytes and two protocol bytes). If disabled, it indicates that
 965         the packets will be pure IP packets. Defaults to
 966         <literal>no</literal>.</para>
 967         </listitem>
 968       </varlistentry>
 969       <varlistentry>
 970         <term><varname>VNetHeader=</varname></term>
 971         <listitem><para>Takes a boolean argument. Configures
 972         IFF_VNET_HDR flag for a tap device. It allows sending
 973         and receiving larger Generic Segmentation Offload (GSO)
 974         packets. This may increase throughput significantly.
 975         Defaults to
 976         <literal>no</literal>.</para>
 977         </listitem>
 978       </varlistentry>
 979       <varlistentry>
 980         <term><varname>User=</varname></term>
 981         <listitem><para>User to grant access to the
 982         <filename>/dev/net/tun</filename> device.</para>
 983         </listitem>
 984       </varlistentry>
 985       <varlistentry>
 986         <term><varname>Group=</varname></term>
 987         <listitem><para>Group to grant access to the
 988         <filename>/dev/net/tun</filename> device.</para>
 989         </listitem>
 990       </varlistentry>
 991
 992     </variablelist>
 993
 994   </refsect1>
 995
 996   <refsect1>
 997     <title>[Tap] Section Options</title>
 998
 999     <para>The <literal>[Tap]</literal> section only applies for
1000     netdevs of kind <literal>tap</literal>, and accepts the same keys
1001     as the <literal>[Tun]</literal> section.</para>
1002   </refsect1>
1003
1004   <refsect1>
1005     <title>[Bond] Section Options</title>
1006
1007     <para>The <literal>[Bond]</literal> section accepts the following
1008     key:</para>
1009
1010     <variablelist class='network-directives'>
1011       <varlistentry>
1012         <term><varname>Mode=</varname></term>
1013         <listitem>
1014           <para>Specifies one of the bonding policies. The default is
1015           <literal>balance-rr</literal> (round robin). Possible values are
1016           <literal>balance-rr</literal>,
1017           <literal>active-backup</literal>,
1018           <literal>balance-xor</literal>,
1019           <literal>broadcast</literal>,
1020           <literal>802.3ad</literal>,
1021           <literal>balance-tlb</literal>, and
1022           <literal>balance-alb</literal>.
1023           </para>
1024         </listitem>
1025       </varlistentry>
1026
1027       <varlistentry>
1028         <term><varname>TransmitHashPolicy=</varname></term>
1029         <listitem>
1030           <para>Selects the transmit hash policy to use for slave
1031           selection in balance-xor, 802.3ad, and tlb modes. Possible
1032           values are
1033           <literal>layer2</literal>,
1034           <literal>layer3+4</literal>,
1035           <literal>layer2+3</literal>,
1036           <literal>encap2+3</literal>, and
1037           <literal>encap3+4</literal>.
1038           </para>
1039         </listitem>
1040       </varlistentry>
1041
1042       <varlistentry>
1043         <term><varname>LACPTransmitRate=</varname></term>
1044         <listitem>
1045           <para>Specifies the rate with which link partner transmits
1046           Link Aggregation Control Protocol Data Unit packets in
1047           802.3ad mode. Possible values are <literal>slow</literal>,
1048           which requests partner to transmit LACPDUs every 30 seconds,
1049           and <literal>fast</literal>, which requests partner to
1050           transmit LACPDUs every second. The default value is
1051           <literal>slow</literal>.</para>
1052         </listitem>
1053       </varlistentry>
1054
1055       <varlistentry>
1056         <term><varname>MIIMonitorSec=</varname></term>
1057         <listitem>
1058           <para>Specifies the frequency that Media Independent
1059           Interface link monitoring will occur. A value of zero
1060           disables MII link monitoring. This value is rounded down to
1061           the nearest millisecond. The default value is 0.</para>
1062         </listitem>
1063       </varlistentry>
1064
1065       <varlistentry>
1066         <term><varname>UpDelaySec=</varname></term>
1067         <listitem>
1068           <para>Specifies the delay before a link is enabled after a
1069           link up status has been detected. This value is rounded down
1070           to a multiple of MIIMonitorSec. The default value is
1071           0.</para>
1072         </listitem>
1073       </varlistentry>
1074
1075       <varlistentry>
1076         <term><varname>DownDelaySec=</varname></term>
1077         <listitem>
1078           <para>Specifies the delay before a link is disabled after a
1079           link down status has been detected. This value is rounded
1080           down to a multiple of MIIMonitorSec. The default value is
1081           0.</para>
1082         </listitem>
1083       </varlistentry>
1084
1085       <varlistentry>
1086         <term><varname>LearnPacketIntervalSec=</varname></term>
1087         <listitem>
1088           <para>Specifies the number of seconds between instances where the bonding
1089           driver sends learning packets to each slave peer switch.
1090           The valid range is 1–0x7fffffff; the default value is 1. This option
1091           has an effect only for the balance-tlb and balance-alb modes.</para>
1092         </listitem>
1093       </varlistentry>
1094
1095       <varlistentry>
1096         <term><varname>AdSelect=</varname></term>
1097         <listitem>
1098           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
1099           <literal>stable</literal>,
1100           <literal>bandwidth</literal> and
1101           <literal>count</literal>.
1102           </para>
1103         </listitem>
1104       </varlistentry>
1105
1106       <varlistentry>
1107         <term><varname>FailOverMACPolicy=</varname></term>
1108         <listitem>
1109           <para>Specifies whether the active-backup mode should set all slaves to
1110           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1111           bond's MAC address in accordance with the selected policy. The default policy is none.
1112           Possible values are
1113           <literal>none</literal>,
1114           <literal>active</literal> and
1115           <literal>follow</literal>.
1116           </para>
1117         </listitem>
1118       </varlistentry>
1119
1120       <varlistentry>
1121         <term><varname>ARPValidate=</varname></term>
1122         <listitem>
1123           <para>Specifies whether or not ARP probes and replies should be
1124           validated in any mode that supports ARP monitoring, or whether
1125           non-ARP traffic should be filtered (disregarded) for link
1126           monitoring purposes. Possible values are
1127           <literal>none</literal>,
1128           <literal>active</literal>,
1129           <literal>backup</literal> and
1130           <literal>all</literal>.
1131           </para>
1132         </listitem>
1133       </varlistentry>
1134
1135       <varlistentry>
1136         <term><varname>ARPIntervalSec=</varname></term>
1137         <listitem>
1138           <para>Specifies the ARP link monitoring frequency in milliseconds.
1139           A value of 0 disables ARP monitoring. The default value is 0.
1140           </para>
1141         </listitem>
1142       </varlistentry>
1143
1144       <varlistentry>
1145         <term><varname>ARPIPTargets=</varname></term>
1146         <listitem>
1147           <para>Specifies the IP addresses to use as ARP monitoring peers when
1148           ARPIntervalSec is greater than 0. These are the targets of the ARP request
1149           sent to determine the health of the link to the targets.
1150           Specify these values in IPv4 dotted decimal format. At least one IP
1151           address must be given for ARP monitoring to function. The
1152           maximum number of targets that can be specified is 16. The
1153           default value is no IP addresses.
1154           </para>
1155         </listitem>
1156       </varlistentry>
1157
1158       <varlistentry>
1159         <term><varname>ARPAllTargets=</varname></term>
1160         <listitem>
1161           <para>Specifies the quantity of ARPIPTargets that must be reachable
1162           in order for the ARP monitor to consider a slave as being up.
1163           This option affects only active-backup mode for slaves with
1164           ARPValidate enabled. Possible values are
1165           <literal>any</literal> and
1166           <literal>all</literal>.
1167           </para>
1168         </listitem>
1169       </varlistentry>
1170
1171       <varlistentry>
1172         <term><varname>PrimaryReselectPolicy=</varname></term>
1173         <listitem>
1174           <para>Specifies the reselection policy for the primary slave.  This
1175           affects how the primary slave is chosen to become the active slave
1176           when failure of the active slave or recovery of the primary slave
1177           occurs. This option is designed to prevent flip-flopping between
1178           the primary slave and other slaves.  Possible values are
1179           <literal>always</literal>,
1180           <literal>better</literal> and
1181           <literal>failure</literal>.
1182           </para>
1183         </listitem>
1184       </varlistentry>
1185
1186       <varlistentry>
1187         <term><varname>ResendIGMP=</varname></term>
1188         <listitem>
1189           <para>Specifies the number of IGMP membership reports to be issued after
1190           a failover event. One membership report is issued immediately after
1191           the failover, subsequent packets are sent in each 200ms interval.
1192           The valid range is 0–255. Defaults to 1. A value of 0
1193           prevents the IGMP membership report from being issued in response
1194           to the failover event.
1195           </para>
1196         </listitem>
1197       </varlistentry>
1198
1199       <varlistentry>
1200         <term><varname>PacketsPerSlave=</varname></term>
1201         <listitem>
1202           <para>Specify the number of packets to transmit through a slave before
1203             moving to the next one. When set to 0, then a slave is chosen at
1204             random. The valid range is 0–65535. Defaults to 1. This option
1205             only has effect when in balance-rr mode.
1206           </para>
1207         </listitem>
1208       </varlistentry>
1209
1210       <varlistentry>
1211         <term><varname>GratuitousARP=</varname></term>
1212         <listitem>
1213           <para>Specify the number of peer notifications (gratuitous ARPs and
1214             unsolicited IPv6 Neighbor Advertisements) to be issued after a
1215             failover event.  As soon as the link is up on the new slave,
1216             a peer notification is sent on the  bonding device and each
1217             VLAN sub-device.  This is repeated at each link monitor interval
1218             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1219             greater than 1. The valid range is 0–255. The default value is 1.
1220             These options affect only the active-backup mode.
1221           </para>
1222         </listitem>
1223       </varlistentry>
1224
1225       <varlistentry>
1226         <term><varname>AllSlavesActive=</varname></term>
1227         <listitem>
1228           <para>A boolean. Specifies that duplicate frames (received on inactive ports)
1229           should be dropped when false, or delivered when true. Normally, bonding will drop
1230           duplicate frames (received on inactive ports), which is desirable for
1231           most users. But there are some times it is nice to allow duplicate
1232           frames to be delivered. The default value is false (drop duplicate frames
1233           received on inactive ports).
1234           </para>
1235         </listitem>
1236       </varlistentry>
1237
1238       <varlistentry>
1239         <term><varname>MinLinks=</varname></term>
1240         <listitem>
1241           <para>Specifies the minimum number of links that must be active before
1242           asserting carrier. The default value is 0.
1243           </para>
1244         </listitem>
1245       </varlistentry>
1246     </variablelist>
1247
1248     <para>For more detail information see
1249     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1250     Linux Ethernet Bonding Driver HOWTO</ulink></para>
1251
1252   </refsect1>
1253
1254   <refsect1>
1255     <title>Example</title>
1256     <example>
1257       <title>/etc/systemd/network/25-bridge.netdev</title>
1258
1259       <programlisting>[NetDev]
1260 Name=bridge0
1261 Kind=bridge</programlisting>
1262     </example>
1263
1264     <example>
1265       <title>/etc/systemd/network/25-vlan1.netdev</title>
1266
1267       <programlisting>[Match]
1268 Virtualization=no
1269
1270 [NetDev]
1271 Name=vlan1
1272 Kind=vlan
1273
1274 [VLAN]
1275 Id=1</programlisting>
1276     </example>
1277     <example>
1278       <title>/etc/systemd/network/25-ipip.netdev</title>
1279       <programlisting>[NetDev]
1280 Name=ipip-tun
1281 Kind=ipip
1282 MTUBytes=1480
1283
1284 [Tunnel]
1285 Local=192.168.223.238
1286 Remote=192.169.224.239
1287 TTL=64</programlisting>
1288     </example>
1289     <example>
1290       <title>/etc/systemd/network/25-tap.netdev</title>
1291       <programlisting>[NetDev]
1292 Name=tap-test
1293 Kind=tap
1294
1295 [Tap]
1296 MultiQueue=true
1297 PacketInfo=true</programlisting> </example>
1298
1299     <example>
1300       <title>/etc/systemd/network/25-sit.netdev</title>
1301       <programlisting>[NetDev]
1302 Name=sit-tun
1303 Kind=sit
1304 MTUBytes=1480
1305
1306 [Tunnel]
1307 Local=10.65.223.238
1308 Remote=10.65.223.239</programlisting>
1309     </example>
1310
1311     <example>
1312       <title>/etc/systemd/network/25-gre.netdev</title>
1313       <programlisting>[NetDev]
1314 Name=gre-tun
1315 Kind=gre
1316 MTUBytes=1480
1317
1318 [Tunnel]
1319 Local=10.65.223.238
1320 Remote=10.65.223.239</programlisting>
1321     </example>
1322
1323     <example>
1324       <title>/etc/systemd/network/25-vti.netdev</title>
1325
1326       <programlisting>[NetDev]
1327 Name=vti-tun
1328 Kind=vti
1329 MTUBytes=1480
1330
1331 [Tunnel]
1332 Local=10.65.223.238
1333 Remote=10.65.223.239</programlisting>
1334     </example>
1335
1336     <example>
1337       <title>/etc/systemd/network/25-veth.netdev</title>
1338       <programlisting>[NetDev]
1339 Name=veth-test
1340 Kind=veth
1341
1342 [Peer]
1343 Name=veth-peer</programlisting>
1344     </example>
1345
1346     <example>
1347       <title>/etc/systemd/network/25-bond.netdev</title>
1348       <programlisting>[NetDev]
1349 Name=bond1
1350 Kind=bond
1351
1352 [Bond]
1353 Mode=802.3ad
1354 TransmitHashPolicy=layer3+4
1355 MIIMonitorSec=1s
1356 LACPTransmitRate=fast
1357 </programlisting>
1358     </example>
1359
1360     <example>
1361       <title>/etc/systemd/network/25-dummy.netdev</title>
1362       <programlisting>[NetDev]
1363 Name=dummy-test
1364 Kind=dummy
1365 MACAddress=12:34:56:78:9a:bc</programlisting>
1366     </example>
1367     <example>
1368       <title>/etc/systemd/network/25-vrf.netdev</title>
1369       <para>Create a VRF interface with table 42.</para>
1370       <programlisting>[NetDev]
1371 Name=vrf-test
1372 Kind=vrf
1373
1374 [VRF]
1375 Table=42</programlisting>
1376     </example>
1377
1378     <example>
1379       <title>/etc/systemd/network/25-macvtap.netdev</title>
1380       <para>Create a MacVTap device.</para>
1381       <programlisting>[NetDev]
1382 Name=macvtap-test
1383 Kind=macvtap
1384       </programlisting>
1385     </example>
1386   </refsect1>
1387   <refsect1>
1388     <title>See Also</title>
1389     <para>
1390       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1391       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1392       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1393       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1394     </para>
1395   </refsect1>
1396
1397 </refentry>