1<?xml version='1.0'?> <!--*-nxml-*-->
2<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
5
6<refentry id="systemd-networkd.service" conditional='ENABLE_NETWORKD'>
7
8  <refentryinfo>
9    <title>systemd-networkd.service</title>
10    <productname>systemd</productname>
11  </refentryinfo>
12
13  <refmeta>
14    <refentrytitle>systemd-networkd.service</refentrytitle>
15    <manvolnum>8</manvolnum>
16  </refmeta>
17
18  <refnamediv>
19    <refname>systemd-networkd.service</refname>
20    <refname>systemd-networkd</refname>
21    <refpurpose>Network manager</refpurpose>
22  </refnamediv>
23
24  <refsynopsisdiv>
25    <para><filename>systemd-networkd.service</filename></para>
26    <para><filename>/usr/lib/systemd/systemd-networkd</filename></para>
27  </refsynopsisdiv>
28
29  <refsect1>
30    <title>Description</title>
31
32    <para><command>systemd-networkd</command> is a system service that
33    manages networks. It detects and configures network devices as
34    they appear, as well as creating virtual network devices.</para>
35
36    <para>To configure low-level link settings independently of
37    networks, see
38    <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
39
40    <para><command>systemd-networkd</command> will create network devices based
41    on the configuration in
42    <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>
43    files, respecting the [Match] sections in those files.</para>
44
45    <para><command>systemd-networkd</command> will manage network addresses and
46    routes for any link for which it finds a <filename>.network</filename> file
47    with an appropriate [Match] section, see
48    <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
49    For those links, it will flush existing network addresses and routes when
50    bringing up the device. Any links not matched by one of the
51    <filename>.network</filename> files will be ignored. It is also possible to
52    explicitly tell <filename>systemd-networkd</filename> to ignore a link by
53    using <varname>Unmanaged=yes</varname> option, see
54    <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
55    </para>
56
57    <para>When <filename>systemd-networkd</filename> exits, it generally leaves
58    existing network devices and configuration intact. This makes it possible to
59    transition from the initramfs and to restart the service without breaking
60    connectivity. This also means that when configuration is updated and
61    <filename>systemd-networkd</filename> is restarted, netdev interfaces for
62    which configuration was removed will not be dropped, and may need to be
63    cleaned up manually.</para>
64
65    <para><command>systemd-networkd</command> may be introspected and controlled at runtime using
66    <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
67    </para>
68  </refsect1>
69
70  <refsect1><title>Configuration Files</title>
71    <para>The configuration files are read from the files located in the
72    system network directory <filename>/usr/lib/systemd/network</filename>,
73    the volatile runtime network directory
74    <filename>/run/systemd/network</filename> and the local administration
75    network directory <filename>/etc/systemd/network</filename>.</para>
76
77    <para>Networks are configured in <filename>.network</filename>
78    files, see
79    <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
80    and virtual network devices are configured in
81    <filename>.netdev</filename> files, see
82    <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
83    </para>
84  </refsect1>
85
86  <refsect1>
87    <title>See Also</title>
88    <para>
89      <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
90      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
91      <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
92      <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
93      <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
94      <citerefentry><refentrytitle>systemd-networkd-wait-online.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
95      <citerefentry><refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
96    </para>
97  </refsect1>
98
99</refentry>
100