network: beef up ipv6 RA support considerably

[thirdparty/systemd.git] / man / systemd.network.xml

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 821e22aff88f6ad658681199d605cff092f7beec..487bb2ab3f97e2ddcfe3e80421358750490177fd 100644 (file)
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -528,23 +528,19 @@
         </varlistentry>
         <varlistentry>
           <term><varname>IPv6AcceptRouterAdvertisements=</varname></term>
-          <listitem><para>Force the setting of the <filename>accept_ra</filename>
-          (router advertisements) setting for the interface.
-          When unset, the kernel default is used, and router
-          advertisements are accepted only when local forwarding
-          is disabled for that interface.
-          When router advertisements are accepted, they will
-          trigger the start of the DHCPv6 client if the relevant
-          flags are passed, or if no routers are found on the link.
-          Takes a boolean. If true, router advertisements are
-          accepted, when false, router advertisements are ignored,
-          independently of the local forwarding state.</para>
-
-          <para>See
-          <ulink url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink>
-          in the kernel documentation, but note that systemd's
-          setting of <constant>1</constant> corresponds to
-          kernel's setting of <constant>2</constant>.</para>
+          <listitem><para>Enable or disable IPv6 Router Advertisement (RA) reception support for the interface.  Takes
+          a boolean parameter. If true, RAs are accepted; if false, RAs are ignored, independently of the local
+          forwarding state. When not set, the kernel default is used, and RAs are accepted only when local forwarding
+          is disabled for that interface.  When RAs are accepted, they may trigger the start of the DHCPv6 client if
+          the relevant flags are set in the RA data, or if no routers are found on the link.</para>
+
+          <para>Further settings for the IPv6 RA support may be configured in the
+          <literal>[IPv6AcceptRouterAdvertisements]</literal> section, see below.</para>
+
+          <para>Also see <ulink
+          url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink> in the kernel
+          documentation regarding <literal>accept_ra</literal>, but note that systemd's setting of
+          <constant>1</constant> (i.e. true) corresponds to kernel's setting of <constant>2</constant>.</para>
         </listitem>
         </varlistentry>
         <varlistentry>
@@ -799,7 +795,7 @@
             false.</para>
 
             <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
-            of all host names, in particular to single-label names. It is generally safer to use the supplied domain
+            of all host names, in particular of single-label names. It is generally safer to use the supplied domain
             only as routing domain, rather than as search domain, in order to not have it affect local resolution of
             single-label names.</para>
 
@@ -898,6 +894,47 @@
       </variablelist>
     </refsect1>
 
+  <refsect1>
+    <title>[IPv6AcceptRouterAdvertisements] Section Options</title>
+      <para>The <literal>[IPv6AcceptRouterAdvertisements]</literal> section configures the IPv6 Router Advertisement
+      (RA) client, if it is enabled with the <varname>IPv6AcceptRouterAdvertisements=</varname> setting described
+      above:</para>
+
+      <variablelist class='network-directives'>
+        <varlistentry>
+          <term><varname>UseDNS=</varname></term>
+          <listitem>
+            <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take
+            precedence over any statically configured ones.</para>
+
+            <para>This corresponds to the <option>nameserver</option> option in <citerefentry
+            project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+          </listitem>
+        </varlistentry>
+
+        <varlistentry>
+          <term><varname>UseDomains=</varname></term>
+          <listitem>
+            <para>Takes a boolean argument, or the special value <literal>route</literal>. When true, the domain name
+            received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, similar to
+            the effect of the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name
+            received via IPv6 RA will be used for routing DNS queries only, but not for searching, similar to the
+            effect of the <option>Domains=</option> setting when the argument is prefixed with
+            <literal>~</literal>. Defaults to false.</para>
+
+            <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution
+            of all host names, in particular of single-label names. It is generally safer to use the supplied domain
+            only as routing domain, rather than as search domain, in order to not have it affect local resolution of
+            single-label names.</para>
+
+            <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry
+            project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+          </listitem>
+        </varlistentry>
+      </variablelist>
+  </refsect1>
+
+
   <refsect1>
     <title>[DHCPServer] Section Options</title>
     <para>The <literal>[DHCPServer]</literal> section contains