man: extend explanation for ConfigureWithoutCarrier= in systemd.network(5)

Prompted by #33702.

(cherry picked from commit 347c8822d1a8a5b70624920b3de2a91d4e0fca91)

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 68d0c9be59be6c6a4da15e07623b284296a7919c..1e3f24499cc3edbaef7f49b7c32de51c63baf966 100644 (file)
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -1207,6 +1207,18 @@ DuplicateAddressDetection=none</programlisting></para>
           carrier. Defaults to false. If enabled, and the <varname>IgnoreCarrierLoss=</varname> setting
           is not explicitly set, then it is enabled as well.</para>
 
+          <para>With this enabled, to make the interface enter the <literal>configured</literal> state,
+          which is required to make <command>systemd-networkd-wait-online</command> work properly for the
+          interface, all dynamic address configuration mechanisms like <varname>DHCP=</varname> and
+          <varname>IPv6AcceptRA=</varname> (which is enabled by default in most cases) need to be disabled.
+          Also, <varname>DuplicateAddressDetection=</varname> (which is enabled by default for IPv4
+          link-local addresses and all IPv6 addresses) needs to be disabled for all static address
+          configurations. Otherwise, without carrier, the interface will be stuck in the
+          <literal>configuring</literal> state, and <command>systemd-networkd-wait-online</command> for the
+          interface will timeout. Also, it is recommended to set
+          <varname>RequiredForOnline=no-carrier</varname> to make
+          <command>systemd-networkd-wait-online</command> work for the interface.</para>
+
           <xi:include href="version-info.xml" xpointer="v235"/>
         </listitem>
       </varlistentry>