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NetworkManager-wait-online.service(8) manual page
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<refentry id="NetworkManager-wait-online.service">
<refentryinfo>
<title>NetworkManager-wait-online.service</title>
<author>NetworkManager developers</author>
</refentryinfo>
<refmeta>
<refentrytitle>NetworkManager-wait-online.service</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class="source">NetworkManager-wait-online.service</refmiscinfo>
<refmiscinfo class="manual">Network management daemons</refmiscinfo>
<refmiscinfo class="version">&NM_VERSION;</refmiscinfo>
</refmeta>
<refnamediv>
<refname>NetworkManager-wait-online.service</refname>
<refpurpose>Wait for the network to come online</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
The <literal>NetworkManager-wait-online</literal> service is a <literal>oneshot</literal>
systemd service that delays reaching the <literal>network-online</literal> target until
NetworkManager reports that the startup is completed on the D-Bus.
</para>
<para>
When the system boots, for example, remote mounts defined in <literal>/etc/fstab</literal>,
require that the network is up. For this, these systemd units contain the
<literal>After=network-online.target</literal> setting to order themselves after this
target. <literal>NetworkManager-wait-online</literal> ensures that the
<literal>network-online</literal> target is reached only after the network is available.
</para>
<para>
Optimally, all services on the host react dynamically to network changes and systemd
services do not need to be configured to start after reaching the
<literal>network-online</literal> target. In this case,
<literal>NetworkManager-wait-online.service</literal> has no effect and does not delay
the boot time. On the other hand, if you encounter a long boot time due to the delay
of <literal>NetworkManager-wait-online</literal>, investigate the services that require
network access and fix them.
</para>
<para>
Except for the time out value in the <literal>NetworkManager-wait-online.service</literal>
unit, you cannot configure this service. Instead, settings in NetworkManager and the
connection profiles affect the behavior:
</para>
<itemizedlist>
<listitem>
<para>
Startup is not complete as long as NetworkManager profiles are in an activating
state. During boot, NetworkManager starts profiles with the
<literal>connection.autoconnect=yes</literal> setting. If activation fails,
NetworkManager retries the activation depending on the value of the
<literal>connection.autoconnect-retries</literal> setting.
</para>
<para>
NetworkManager reports startup complete when all profiles and devices are either
activated or in a disconnect state and no further events are expected.
</para>
</listitem>
<listitem>
<para>
When a device reaches the activate state depends on its configuration. For example,
with a profile that has both IPv4 and IPv6 enabled, by default, NetworkManager
considers the device as fully activated already when only one of the address
families is ready.
</para>
<para>
The <literal>ipv4.may-fail</literal> and <literal>ipv6.may-fail</literal> settings
control this behavior. Additionally, the following settings influence when the
two address families complete: <literal>ipv4.required-timeout</literal>,
<literal>ipv6.required-timeout</literal>, <literal>ipv4.dhcp-timeout</literal>,
and <literal>ipv6.ra-timeout</literal>. For details, see
<link linkend='nm-settings-nmcli'><citerefentry><refentrytitle>nm-settings-nmcli</refentrytitle><manvolnum>5</manvolnum></citerefentry></link>.
</para>
</listitem>
<listitem>
<para>
NetworkManager cannot set IP addresses on bridge and bond devices that have ports
that do not auto-activate. Because of this configuration error,
<literal>NetworkManager-wait-online</literal> blocks until the service reaches
its timeout value.
</para>
</listitem>
<listitem>
<para>
Dispatcher scripts for the <literal>pre-up</literal> event run at a late stage
during activation of a profile. These scripts block the activation for when
NetworkManager considers the profile fully activated. For details, see
<link linkend='NetworkManager-dispatcher'><citerefentry><refentrytitle>NetworkManager-dispatcher</refentrytitle><manvolnum>8</manvolnum></citerefentry></link>.
</para>
</listitem>
<listitem>
<para>
The property <literal>connection.wait-activation-delay</literal> adds an additional
delay during activation and delays startup complete. This setting works around
certain cases where a device is known to not be ready for a certain amount of time.
</para>
</listitem>
<listitem>
<para>
The property <literal>connection.wait-device-timeout</literal> in the connection
profiles cause a delay until the waiting devices appear. This is useful if the
driver takes a longer time to detect the networking interfaces. This setting is
similar to the <literal>connection.gateway-ping-timeout</literal> property.
</para>
</listitem>
<listitem>
<para>
With Wi-Fi devices, NetworkManager needs to wait for the first scan result to
know which networks are available. That adds a delay.
</para>
</listitem>
<listitem>
<para>
With Ethernet devices, NetworkManager waits for the carrier until the value in
<literal>[device*].carrier-wait-timeout</literal> is reached. This is because some
devices take a long time to detect the carrier. Consequently, booting with cable
unplugged, unnecessarily delays <literal>NetworkManager-wait-online.service</literal>.
</para>
</listitem>
</itemizedlist>
</refsect1>
<refsect1>
<title>Bugs</title>
<para>
Please report any bugs in NetworkManager at the
<ulink url="https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues">NetworkManager issue tracker</ulink>.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<ulink url="https://networkmanager.dev">NetworkManager home page</ulink>,
<link linkend='NetworkManager'><citerefentry><refentrytitle>NetworkManager</refentrytitle><manvolnum>8</manvolnum></citerefentry></link>,
<link linkend='nm-online'><citerefentry><refentrytitle>nm-online</refentrytitle><manvolnum>1</manvolnum></citerefentry></link>,
the <literal>network-online.target</literal> description in <link linkend='systemd.special'><citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry></link>
</para>
</refsect1>
</refentry>
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