gateway addresses, ordered by their metric. This assigns a stable hostname to the current gateway,
useful for referencing it independently of the current network configuration state.</para></listitem>
+ <listitem><para>The hostname <literal>_outbound</literal> is resolved to the local IPv4 and IPv6
+ addresses that are most likely used for communication with other hosts. This is determined by
+ requesting a routing decision to the configured default gateways from the kernel and then using the
+ local IP addresses selected by this decision. This hostname is only available if there is at least one
+ local default gateway configured. This assigns a stable hostname to the local outbound IP addresses,
+ useful for referencing them independently of the current network configuration state.</para></listitem>
+
<listitem><para>The mappings defined in <filename>/etc/hosts</filename> are resolved to their
configured addresses and back, but they will not affect lookups for non-address types (like MX).
Support for <filename>/etc/hosts</filename> may be disabled with <varname>ReadEtcHosts=no</varname>,
<listitem><para>Queries for the address records (A and AAAA) of single-label non-synthesized names are
resolved via unicast DNS using search domains. For any interface which defines search domains, such
- look-ups are routed to that interface, suffixed with each of the search domains defined on that
- interface in turn. When global search domains are defined, such look-ups are routed to all interfaces,
- suffixed by each of the global search domains in turn. Additionally, lookup of single-label names via
- unicast DNS may be enabled with the <varname>ResolveUnicastSingleLabel=yes</varname> setting. The
- details of which servers are queried and how the final reply is chosen are described below. Note that
- this means that address queries for single-label names are never sent out to remote DNS servers by
- default, and resoulution is only possible if search domains are defined.</para></listitem>
+ look-ups are routed to the servers defined for that interface, suffixed with each of those search
+ domains. When global search domains are defined, such look-ups are routed to the global servers. For
+ each search domain, queries are performed by suffixing the name with each of the search domains in
+ turn. Additionally, lookup of single-label names via unicast DNS may be enabled with the
+ <varname>ResolveUnicastSingleLabel=yes</varname> setting. The details of which servers are queried and
+ how the final reply is chosen are described below. Note that this means that address queries for
+ single-label names are never sent out to remote DNS servers by default, and resolution is only
+ possible if search domains are defined.</para></listitem>
<listitem><para>Multi-label names with the domain suffix <literal>.local</literal> are resolved using
MulticastDNS on all local interfaces where MulticastDNS is enabled. As with LLMNR, IPv4 address lookups
control of the client library. <filename>nss-dns</filename> will first try to resolve names using
search domains and even if those queries are routed to <filename>systemd-resolved</filename>, it will
send them out over the network using the usual rules for multi-label name routing <footnote><para>For
- example, if <filename>/etc/
nsswitch.conf</filename> has <programlisting>nameserver 127.0.0.53
+ example, if <filename>/etc/
resolv.conf</filename> has <programlisting>nameserver 127.0.0.53
search foobar.com barbar.com
</programlisting>and we look up <literal>localhost</literal>, <filename>nss-dns</filename> will send
the following queries to <filename>systemd-resolved</filename> listening on 127.0.0.53:53: first
fragility in both directions: a valid global name could be obscured by a local name, and resolution of
a relative local name could suddenly break when a new top-level domain is created, or when a new
subdomain of a top-level domain in registered. Resolving any given name as either relative or absolute
- avoids this ambiguity.)</para></footnote></para></listitem>
+ avoids this ambiguity.</para></footnote></para></listitem>
<listitem><para>This resolver has a notion of the special <literal>.local</literal> domain used for
MulticastDNS, and will not route queries with that suffix to unicast DNS servers unless explicitly
projects / thirdparty / systemd.git / blobdiff