source: BOOK/network/common/systemd-network.xml@ d4b275b

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  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
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<sect1 id="ch-systemd-network">
  <?dbhtml filename="systemd-network.html"?>

  <title>Networking Configuration with Systemd-networkd</title>

  <sect2 role="interface-config">
    <title>Network Interface Configuration</title>

    <note><para>Udev may assign random Network Card Interface names
    for some network cards such as enp2s1. If you are not sure what
    your Network Card Interface name is, you can always run
    <command>ip l</command> after you have booted your system. It is important
    that the <envar>Name</envar> variable in
    <filename>/etc/systemd/network</filename> contain the correct Network Card
    Interface name (e.g. <envar>Name=enp2s1</envar> or
    <envar>Name=eth0</envar>) or systemd will fail to bring
    up your network interface.</para></note>

    <sect3 role="static">
      <title>Static Network Interface Configuration</title>

      <para><command>systemd-networkd</command> uses
      <filename>/etc/system/network</filename> for configuration files. Refer
      to systemd.network(5) and systemd.netdev(5). Configure a network
      interface with a config file. Adjust Name= as required:</para>

  <screen><userinput>cd /etc/systemd/network &amp;&amp;
cat &gt; static.network &lt;&lt; "EOF"
[Match]
Name=enp2s0

[Network]
Address=192.168.1.1/24
Gateway=192.168.1.2
EOF</userinput></screen>

      <para os="var-ob">The values of these variables must be changed in every
      file to match the proper setup.</para>

      <para os="var-i">The <envar>Name</envar> variable defines the interface
      name, for example, eth0. It is required for all network device
      configuration files.</para>

      <para>The <envar>Gateway</envar> variable should contain the default
      gateway IP address, if one is present. If not, then comment out the
      variable entirely.</para>

      <para>For more information see the <command>systemd.netdev</command> man page.</para>

    </sect3>

    <sect3 role="dhcp">
      <title>Connecting to a network with DHCP</title>

    <para><command>systemd-networkd</command> uses
    <filename>/etc/systemd/network</filename> for configuration files. Refer
    to <filename>systemd.network(5)</filename> and
    <filename>systemd.netdev(5)</filename>. Configure a network interface
    with a config file. Adjust Name= as required:</para>

<screen><userinput>cd /etc/systemd/network &amp;&amp;
cat &gt; dhcp.network &lt;&lt; "EOF"
[Match]
Name=enp2s0

[Network]
DHCP=yes
EOF</userinput></screen>

    <para><command>systemd-networkd</command> will automatically configure
    <filename>/run/systemd/network/resolv.conf</filename> when using DHCP.
    If you did not manually create <filename>/etc/resolv.conf</filename>,
    create a symlink:</para>

<screen><userinput>ln -sv /run/systemd/network/resolv.conf /etc</userinput></screen>

    </sect3>

  </sect2>

  <sect2 role="timesyncd">
    <title>Using Timesyncd</title>

    <para>Systemd includes a simple NTP client daemon,
    <command>systemd-timesyncd</command>, though it is disabled by
    default. If you want to enable it, you will first need to add a required
    user and group:</para>

<screen><userinput>groupadd -g &gid-systemd-timesync; systemd-timesync
useradd -g systemd-timesync -u &uid-systemd-timesync; -d /dev/null -s /bin/false systemd-timesync</userinput></screen>

    <para>Then, actually enable <command>systemd-timesyncd</command> so that
    it will run on system boot:</para>

<screen><userinput>systemctl enable systemd-timesyncd</userinput></screen>

    <para>You can configure <command>systemd-timesyncd</command> by editing
    <filename>/etc/systemd/timesyncd.conf</filename>.</para>

  <para>Continue to <xref linkend="chapter-bootable"/>.</para>

  </sect2>

</sect1>