diff options
| -rw-r--r-- | man/systemd-resolved.service.xml | 43 |
1 files changed, 36 insertions, 7 deletions
diff --git a/man/systemd-resolved.service.xml b/man/systemd-resolved.service.xml index 3d7bb52d6..d7334e01e 100644 --- a/man/systemd-resolved.service.xml +++ b/man/systemd-resolved.service.xml @@ -143,16 +143,45 @@ lookup zones on all matching interfaces). If the lookup failed on all interfaces, the last failing response is returned.</para> - <para>Routing of lookups may be influenced by configuring - per-interface domain names. See - <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for details. Lookups for a hostname ending in one of the - per-interface domains are exclusively routed to the matching - interfaces.</para> + <para>Routing of lookups may be influenced by configuring per-interface domain names and other settings. See + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> and + <citerefentry><refentrytitle>resolvectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for details. The + following query routing logic applies for unicast DNS traffic:</para> + + <itemizedlist> + <listitem><para>If a name to look up matches (that is: is equal to or has as suffix) any of the configured search + or route-only domains of any link (or the globally configured DNS settings), the "best matching" + search/route-only domain is determined: the matching one with the most labels. The query is then sent to all DNS + servers of any links or the globally configured DNS servers associated with this "best matching" + search/route-only domain. (Note that more than one link might have this same "best matching" search/route-only + domain configured, in which case the query is sent to all of them in parallel).</para></listitem> + + <listitem><para>If a query does not match any configured search/route-only domain (neither per-link nor global), + it is sent to all DNS servers that are configured on links with the "DNS default route" option set, as well as + the globally configured DNS server.</para></listitem> + + <listitem><para>If there is no link configured as "DNS default route" and no global DNS server configured, the + compiled-in fallback DNS server is used.</para></listitem> + + <listitem><para>Otherwise the query is failed as no suitable DNS servers could be determined.</para></listitem> + </itemizedlist> + + <para>The "DNS default route" option is a boolean setting configureable with <command>resolvectl</command> or in + <filename>.network</filename> files. If not set, it is implicitly determined based on the configured DNS domains + for a link: if there's any route-only domain (not matching <literal>~.</literal>) it defaults to false, otherwise + to true.</para> + + <para>Effectively this means: in order to preferably route all DNS queries not explicitly matched by + search/route-only domain configuration to a specific link, configure a <literal>~.</literal> route-only domain on + it. This will ensure that other links will not be considered for the queries (unless they too carry such a + route-only domain). In order to route all such DNS queries to a specific link only in case no other link is + preferable, then set the "DNS default route" option for the link to true, and do not configure a + <literal>~.</literal> route-only domain on it. Finally, in order to ensure that a specific link never receives any + DNS traffic not matching any of its configured search/route-only domains, set the "DNS default route" option for it + to false.</para> <para>See the <ulink url="https://www.freedesktop.org/wiki/Software/systemd/resolved"> resolved D-Bus API Documentation</ulink> for information about the APIs <filename>systemd-resolved</filename> provides.</para> - </refsect1> <refsect1> |