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| -rw-r--r-- | man/systemd.network.xml | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/man/systemd.network.xml b/man/systemd.network.xml index 08dd157e31..0af927db19 100644 --- a/man/systemd.network.xml +++ b/man/systemd.network.xml @@ -467,24 +467,31 @@ <varlistentry> <term><varname>Domains=</varname></term> <listitem> - <para>The domains used for DNS host name resolution on this link. Takes a list of DNS domain names which - are used as search suffixes for extending single-label host names (host names containing no dots) to become - fully qualified domain names (FQDNs). If a single-label host name is resolved on this interface, each of - the specified search domains are appended to it in turn, converting it into a fully qualified domain name, - until one of them may be successfully resolved.</para> - - <para>The specified domains are also used for routing of DNS queries: look-ups for host names ending in the - domains specified here are preferably routed to the DNS servers configured for this interface. If a domain - name is prefixed with <literal>~</literal>, the domain name becomes a pure "routing" domain, the DNS server - is used for the given domain names only and is not used in the described domain search logic. By specifying a - routing domain of <literal>~.</literal> (the tilde indicating definition of a routing domain, the dot - referring to the DNS root domain which is the implied suffix of all valid DNS names) it is possible to - route all DNS traffic preferably to the DNS server specified for this interface. The route domain logic is - particularly useful on multi-homed hosts with DNS servers serving particular private DNS zones on each - interface.</para> + <para>A list of domains which should be resolved using the DNS servers on this link. Each item in the list + should be a domain name, optionally prefixed with a tilde (<literal>~</literal>). The domains with the + prefix are called "routing-only domains". The domains without the prefix are called "search domains" and + are first used as search suffixes for extending single-label host names (host names containing no dots) to + become fully qualified domain names (FQDNs). If a single-label host name is resolved on this interface, + each of the specified search domains are appended to it in turn, converting it into a fully qualified + domain name, until one of them may be successfully resolved.</para> + + <para>Both "search" and "routing-only" domains are used for routing of DNS queries: look-ups for host names + ending in those domains (hence also single label names, if any "search domains" are listed), are routed to + the DNS servers configured for this interface. The domain routing logic is particularly useful on + multi-homed hosts with DNS servers serving particular private DNS zones on each interface.</para> + + <para>The "routing-only" domain <literal>~.</literal> (the tilde indicating definition of a routing domain, + the dot referring to the DNS root domain which is the implied suffix of all valid DNS names) has special + effect. It causes all DNS traffic which does not match another configured domain routing entry to be routed + to DNS servers specified for this interface. This setting is useful to prefer a certain set of DNS servers + if a link on which they are connected is available.</para> <para>This setting is read by - <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + "Search domains" correspond to the <varname>domain</varname> and <varname>search</varname> entries in + <citerefentry><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + Domain name routing has no equivalent in the traditional glibc API, which has no concept of domain + name servers limited to a specific link.</para> </listitem> </varlistentry> <varlistentry> |