path: root/man/systemd.netdev.xml

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<refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>

  <refentryinfo>
    <title>systemd.network</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Tom</firstname>
        <surname>Gundersen</surname>
        <email>teg@jklm.no</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd.netdev</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd.netdev</refname>
    <refpurpose>Virtual Network Device configuration</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Network setup is performed by
    <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
    </para>

    <para>Virtual Network Device files must have the extension
    <filename>.netdev</filename>; other extensions are ignored.
    Virtual network devices are created as soon as networkd is
    started. If a netdev with the specified name already exists,
    networkd will use that as-is rather than create its own. Note that
    the settings of the pre-existing netdev will not be changed by
    networkd.</para>

    <para>The <filename>.netdev</filename> files are read from the
    files located in the system network directory
    <filename>/usr/lib/systemd/network</filename>, the volatile
    runtime network directory
    <filename>/run/systemd/network</filename> and the local
    administration network directory
    <filename>/etc/systemd/network</filename>. All configuration files
    are collectively sorted and processed in lexical order, regardless
    of the directories in which they live. However, files with
    identical filenames replace each other. Files in
    <filename>/etc</filename> have the highest priority, files in
    <filename>/run</filename> take precedence over files with the same
    name in <filename>/usr/lib</filename>. This can be used to
    override a system-supplied configuration file with a local file if
    needed; a symlink in <filename>/etc</filename> with the same name
    as a configuration file in <filename>/usr/lib</filename>, pointing
    to <filename>/dev/null</filename>, disables the configuration file
    entirely.</para>

  </refsect1>

  <refsect1>
    <title>Supported netdev kinds</title>

    <para>The following kinds of virtual network devices may be
    configured in <filename>.netdev</filename> files:</para>

    <table>
      <title>Supported kinds of virtual network devices</title>

      <tgroup cols='2'>
        <colspec colname='kind' />
        <colspec colname='explanation' />
        <thead><row>
          <entry>Kind</entry>
          <entry>Description</entry>
        </row></thead>
        <tbody>
          <row><entry><varname>bond</varname></entry>
          <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>

          <row><entry><varname>bridge</varname></entry>
          <entry>A bridge device is a software switch, each of its slave devices and the bridge itself are ports of the switch.</entry></row>

          <row><entry><varname>dummy</varname></entry>
          <entry>A dummy device drops all packets sent to it.</entry></row>

          <row><entry><varname>gre</varname></entry>
          <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>

          <row><entry><varname>gretap</varname></entry>
          <entry>A Level 2 GRE tunnel over IPv4.</entry></row>

          <row><entry><varname>ip6gre</varname></entry>
          <entry>A Level 3 GRE tunnel over IPv6.</entry></row>

          <row><entry><varname>ip6tnl</varname></entry>
          <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>

          <row><entry><varname>ip6gretap</varname></entry>
          <entry>An Level 2 GRE tunnel over IPv6.</entry></row>

          <row><entry><varname>ipip</varname></entry>
          <entry>An IPv4 over IPv4 tunnel.</entry></row>

          <row><entry><varname>ipvlan</varname></entry>
          <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>

          <row><entry><varname>macvlan</varname></entry>
          <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>

          <row><entry><varname>sit</varname></entry>
          <entry>An IPv6 over IPv4 tunnel.</entry></row>

          <row><entry><varname>tap</varname></entry>
          <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>

          <row><entry><varname>tun</varname></entry>
          <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>

          <row><entry><varname>veth</varname></entry>
          <entry>An ethernet tunnel between a pair of network devices.</entry></row>

          <row><entry><varname>vlan</varname></entry>
          <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>

          <row><entry><varname>vti</varname></entry>
          <entry>An IPv4 over IPSec tunnel.</entry></row>

          <row><entry><varname>vxlan</varname></entry>
          <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
        </tbody>
      </tgroup>
    </table>

  </refsect1>

  <refsect1>
    <title>[Match] Section Options</title>

    <para>A virtual network device is only created if the
    <literal>[Match]</literal> section matches the current
    environment, or if the section is empty. The following keys are
    accepted:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Host=</varname></term>
        <listitem>
          <para>Matches against the hostname or machine ID of the
          host. See <literal>ConditionHost=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Virtualization=</varname></term>
        <listitem>
          <para>Checks whether the system is executed in a virtualized
          environment and optionally test whether it is a specific
          implementation. See
          <literal>ConditionVirtualization=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>KernelCommandLine=</varname></term>
        <listitem>
          <para>Checks whether a specific kernel command line option
          is set (or if prefixed with the exclamation mark unset). See
          <literal>ConditionKernelCommandLine=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Architecture=</varname></term>
        <listitem>
          <para>Checks whether the system is running on a specific
          architecture. See <literal>ConditionArchitecture=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>

  </refsect1>

  <refsect1>
    <title>[NetDev] Section Options</title>

      <para>The <literal>[NetDev]</literal> section accepts the
      following keys:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Description=</varname></term>
          <listitem>
            <para>A free-form description of the netdev.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Name=</varname></term>
          <listitem>
            <para>The interface name used when creating the netdev.
            This option is compulsory.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>Kind=</varname></term>
          <listitem>
            <para>The netdev kind. This option is compulsory. See the
            <literal>Supported netdev kinds</literal> section for the
            valid keys.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MTUBytes=</varname></term>
          <listitem>
            <para>The maximum transmission unit in bytes to set for
            the device. The usual suffixes K, M, G, are supported and
            are understood to the base of 1024. This key is not
            currently suported for <literal>tun</literal> or
            <literal>tap</literal> devices.
            </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>The MAC address to use for the device. If none is
            given, one is generated based on the interface name and
            the
            <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
            This key is not currently suported for
            <literal>tun</literal> or <literal>tap</literal> devices.
            </para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>

  <refsect1>
    <title>[VLAN] Section Options</title>

      <para>The <literal>[VLAN]</literal> section only applies for
      netdevs of kind <literal>vlan</literal>, and accepts the
      following key:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Id=</varname></term>
          <listitem>
            <para>The VLAN ID to use. An integer in the range 0–4094.
            This option is compulsory.</para>
          </listitem>
        </varlistentry>
      </variablelist>

  </refsect1>

  <refsect1>
    <title>[MACVLAN] Section Options</title>

    <para>The <literal>[MACVLAN]</literal> section only applies for
    netdevs of kind <literal>macvlan</literal>, and accepts the
    following key:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Mode=</varname></term>
        <listitem>
          <para>The MACVLAN mode to use. The supported options are
          <literal>private</literal>,
          <literal>vepa</literal>,
          <literal>bridge</literal>, and
          <literal>passthru</literal>.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>

  </refsect1>

  <refsect1>
    <title>[IPVLAN] Section Options</title>

    <para>The <literal>[IPVLAN]</literal> section only applies for
    netdevs of kind <literal>ipvlan</literal>, and accepts the
    following key:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Mode=</varname></term>
          <listitem>
            <para>The IPVLAN mode to use. The supported options are
            <literal>L2</literal> and <literal>L3</literal>.
            </para>
          </listitem>
      </varlistentry>
    </variablelist>

  </refsect1>

  <refsect1>
    <title>[VXLAN] Section Options</title>
    <para>The <literal>[VXLAN]</literal> section only applies for
    netdevs of kind <literal>vxlan</literal>, and accepts the
    following keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Id=</varname></term>
        <listitem>
          <para>The VXLAN ID to use.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Group=</varname></term>
        <listitem>
          <para>An assigned multicast group IP address.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TOS=</varname></term>
        <listitem>
          <para>The Type Of Service byte value for a vxlan interface.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TTL=</varname></term>
        <listitem>
          <para>A fixed Time To Live N on Virtual eXtensible Local
          Area Network packets. N is a number in the range 1-255. 0
          is a special value meaning that packets inherit the TTL
          value.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MacLearning=</varname></term>
        <listitem>
          <para>A boolean. When true, enables dynamic MAC learning
          to discover remote MAC addresses.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>FDBAgeingSec=</varname></term>
        <listitem>
          <para>The lifetime of Forwarding Database entry learnt by
          the kernel in seconds.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>ARPProxy=</varname></term>
        <listitem>
          <para>A boolean. When true, enables ARP proxy.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>L2MissNotification=</varname></term>
        <listitem>
          <para>A boolean. When true, enables netlink LLADDR miss
          notifications.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>L3MissNotification=</varname></term>
        <listitem>
          <para>A boolean. When true, enables netlink IP ADDR miss
          notifications.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>RouteShortCircuit=</varname></term>
        <listitem>
          <para>A boolean. When true route short circuit is turned
          on.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
  <refsect1>
    <title>[Tunnel] Section Options</title>

    <para>The <literal>[Tunnel]</literal> section only applies for
    netdevs of kind
    <literal>ipip</literal>,
    <literal>sit</literal>,
    <literal>gre</literal>,
    <literal>gretap</literal>,
    <literal>ip6gre</literal>,
    <literal>ip6gretap</literal>,
    <literal>vti</literal>, and
    <literal>ip6tnl</literal> and accepts
    the following keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Local=</varname></term>
        <listitem>
          <para>A static local address for tunneled packets. It must
          be an address on another interface of this host.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Remote=</varname></term>
        <listitem>
          <para>The remote endpoint of the tunnel.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TOS=</varname></term>
        <listitem>
          <para>The Type Of Service byte value for a tunnel interface.
          For details about the TOS see the
          <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
          Service in the Internet Protocol Suite </ulink> document.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>TTL=</varname></term>
        <listitem>
          <para>A fixed Time To Live N on tunneled packets. N is a
          number in the range 1-255. 0 is a special value meaning that
          packets inherit the TTL value. The default value for IPv4
          tunnels is: inherit. The default value for IPv6 tunnels is:
          64.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>DiscoverPathMTU=</varname></term>
        <listitem>
          <para>A boolean. When true, enables Path MTU Discovery on
          the tunnel.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Mode=</varname></term>
        <listitem>
          <para>An <literal>ip6tnl</literal> tunnels can have three
          modes
          <literal>ip6ip6</literal> for IPv6 over IPv6,
          <literal>ipip6</literal> for IPv4 over IPv6 or
          <literal>any</literal> for either.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
  <refsect1>
    <title>[Peer] Section Options</title>

      <para>The <literal>[Peer]</literal> section only applies for
      netdevs of kind <literal>veth</literal> and accepts the
      following key:</para>

      <variablelist class='network-directives'>
        <varlistentry>
          <term><varname>Name=</varname></term>
          <listitem>
            <para>The interface name used when creating the netdev.
            This option is compulsory.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>MACAddress=</varname></term>
          <listitem>
            <para>The peer MACAddress, if not set it is generated in
            the same way as the MAC address of the main
            interface.</para>
          </listitem>
        </varlistentry>
      </variablelist>
  </refsect1>
  <refsect1>
    <title>[Tun] Section Options</title>

    <para>The <literal>[Tun]</literal> section only applies for
    netdevs of kind <literal>tun</literal>, and accepts the following
    keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>OneQueue=</varname></term>
        <listitem><para>Takes a boolean argument. Configures whether
        all packets are queued at the device (enabled), or a fixed
        number of packets are queued at the device and the rest at the
        <literal>qdisc</literal>. Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MultiQueue=</varname></term>
        <listitem><para>Takes a boolean argument. Configures whether
        to use multiple file descriptors (queues) to parallelize
        packets sending and receiving. Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>PacketInfo=</varname></term>
        <listitem><para>Takes a boolean argument. Configures whether
        packets should be prepened with four extra bytes (two flag
        bytes and two protocol bytes). If disabled it indicates that
        the packets will be pure IP packets. Defaults to
        <literal>no</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>User=</varname></term>
        <listitem><para>User to grant access to the
        <filename>/dev/net/tun</filename> device.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Group=</varname></term>
        <listitem><para>Group to grant access to the
        <filename>/dev/net/tun</filename> device.</para>
        </listitem>
      </varlistentry>

    </variablelist>

  </refsect1>

  <refsect1>
    <title>[Tap] Section Options</title>

    <para>The <literal>[Tap]</literal> section only applies for
    netdevs of kind <literal>tap</literal>, and accepts the same keys
    as the <literal>[Tun]</literal> section.</para>
  </refsect1>

  <refsect1>
    <title>[Bond] Section Options</title>

    <para>The <literal>[Bond]</literal> section accepts the following
    key:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Mode=</varname></term>
        <listitem>
          <para>Specifies one of the bonding policies. The default is
          <literal>balance-rr</literal> (round robin). Possible values are
          <literal>balance-rr</literal>,
          <literal>active-backup</literal>,
          <literal>balance-xor</literal>,
          <literal>broadcast</literal>,
          <literal>802.3ad</literal>,
          <literal>balance-tlb</literal>, and
          <literal>balance-alb</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>TransmitHashPolicy=</varname></term>
        <listitem>
          <para>Selects the transmit hash policy to use for slave
          selection in balance-xor, 802.3ad, and tlb modes. Possible
          values are
          <literal>layer2</literal>,
          <literal>layer3+4</literal>,
          <literal>layer2+3</literal>,
          <literal>encap2+3</literal>,
          <literal>802.3ad</literal>, and
          <literal>encap3+4</literal>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>LACPTransmitRate=</varname></term>
        <listitem>
          <para>Specifies the rate with which link partner transmits
          Link Aggregation Control Protocol Data Unit packets in
          802.3ad mode. Possible values are <literal>slow</literal>,
          which requests partner to transmit LACPDUs every 30 seconds,
          and <literal>fast</literal>, which requests partner to
          transmit LACPDUs every second. The default value is
          <literal>slow</literal>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>MIIMonitorSec=</varname></term>
        <listitem>
          <para>Specifies the frequency that Media Independent
          Interface link monitoring will occur. A value of zero
          disables MII link monitoring. This values is rounded down to
          the nearest millisecond. The default value is 0.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>UpDelaySec=</varname></term>
        <listitem>
          <para>Specifies the delay before a link is enabled after a
          link up status has been detected. This value is rounded down
          to a multiple of MIIMonitorSec. The default value is
          0.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>DownDelaySec=</varname></term>
        <listitem>
          <para>Specifies the delay before a link is disabled after a
          link down status has been detected. This value is rounded
          down to a multiple of MIIMonitorSec. The default value is
          0.</para>
        </listitem>
      </varlistentry>

    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>
    <example>
      <title>/etc/systemd/network/bridge.netdev</title>

      <programlisting>[NetDev]
Name=bridge0
Kind=bridge</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/vlan1.netdev</title>

      <programlisting>[Match]
Virtualization=no

[NetDev]
Name=vlan1
Kind=vlan

[VLAN]
Id=1</programlisting>
    </example>
    <example>
      <title>/etc/systemd/network/ipip.netdev</title>
      <programlisting>[NetDev]
Name=ipip-tun
Kind=ipip
MTUBytes=1480

[Tunnel]
Local=192.168.223.238
Remote=192.169.224.239
TTL=64</programlisting>
    </example>
    <example>
      <title>/etc/systemd/network/tap.netdev</title>
      <programlisting>[NetDev]
Name=tap-test
Kind=tap

[Tap]
MultiQueue=true
PacketInfo=true</programlisting> </example>

    <example>
      <title>/etc/systemd/network/sit.netdev</title>
      <programlisting>[NetDev]
Name=sit-tun
Kind=sit
MTUBytes=1480

[Tunnel]
Local=10.65.223.238
Remote=10.65.223.239</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/gre.netdev</title>
      <programlisting>[NetDev]
Name=gre-tun
Kind=gre
MTUBytes=1480

[Tunnel]
Local=10.65.223.238
Remote=10.65.223.239</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/vti.netdev</title>

      <programlisting>[NetDev]
Name=vti-tun
Kind=vti
MTUBytes=1480

[Tunnel]
Local=10.65.223.238
Remote=10.65.223.239</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/veth.netdev</title>
      <programlisting>[NetDev]
Name=veth-test
Kind=veth

[Peer]
Name=veth-peer</programlisting>
    </example>

    <example>
      <title>/etc/systemd/network/dummy.netdev</title>
      <programlisting>[NetDev]
Name=dummy-test
Kind=dummy
MACAddress=12:34:56:78:9a:bc</programlisting>
    </example>

  </refsect1>
  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>