diff options
Diffstat (limited to 'man/systemd-resolved.service.xml')
| -rw-r--r-- | man/systemd-resolved.service.xml | 77 |
1 files changed, 70 insertions, 7 deletions
diff --git a/man/systemd-resolved.service.xml b/man/systemd-resolved.service.xml index 89ec5f8b19..96dc4f6620 100644 --- a/man/systemd-resolved.service.xml +++ b/man/systemd-resolved.service.xml @@ -1,4 +1,4 @@ -<?xml version='1.0'?> <!--*-nxml-*--> +<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> @@ -61,15 +61,77 @@ resolver and an LLMNR resolver and responder. It also generates <filename>/run/systemd/resolve/resolv.conf</filename> for compatibility which may be symlinked from - <filename>/etc/resolv.conf</filename>.</para> + <filename>/etc/resolv.conf</filename>. The glibc NSS module + <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry> + is necessary to allow libc's NSS resolver functions to resolve + host names via <command>systemd-resolved</command>.</para> <para>The DNS servers contacted are determined from the global - settings in - <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, - the per-link static settings in <filename>.network</filename> - files, and the per-link dynamic settings received over DHCP. See + settings in <filename>/etc/systemd/resolved.conf</filename>, the + per-link static settings in <filename>/etc/systemd/network/*.network</filename> files, + and the per-link dynamic settings received over DHCP. See + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + and + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. To improve compatibility + <filename>/etc/resolv.conf</filename> is read in order to discover + configured system DNS servers, however only if it is not a symlink + to <filename>/run/systemd/resolve/resolv.conf</filename> (see above).</para> + + <para><command>systemd-resolved</command> synthesizes DNS RRs for the following cases:</para> + + <itemizedlist> + <listitem><para>The local, configured hostname is resolved to + all locally configured IP addresses ordered by their scope, or + — if none are configured — the IPv4 address 127.0.0.2 (which + is on the local loopback) and the IPv6 address ::1 (which is the + local host).</para></listitem> + + <listitem><para>The hostname <literal>localhost</literal> is + resolved to the IP addresses 127.0.0.1 and + ::1.</para></listitem> + + <listitem><para>The hostname <literal>gateway</literal> is + resolved to all current default routing 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> + </itemizedlist> + + <para>Lookup requests are routed to the available DNS servers + and LLMNR interfaces according to the following rules:</para> + + <itemizedlist> + <listitem><para>Lookups for the special hostname + <literal>localhost</literal> are never routed to the + network.</para></listitem> + + <listitem><para>Single-label names are routed to all local + interfaces capable of IP multicasting, using the LLMNR + protocol. Lookups for IPv4 addresses are only sent via LLMNR on + IPv4, and lookups for IPv6 addresses are only sent via LLMNR on + IPv6. Lookups for the locally configured host name and the + <literal>gateway</literal> host name are never routed to + LLMNR.</para></listitem> + + <listitem><para>Multi-label names are routed to all local + interfaces that have a DNS sever configured, plus the globally + configured DNS server if there is one. Address lookups from the + link-local addres range are never routed to + DNS.</para></listitem> + </itemizedlist> + + <para>If lookups are routed to multiple interfaces, the first + successful response is returned (thus effectively merging the + 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 more details.</para> + for details. Lookups for a hostname ending in one of the + per-interface domains are exclusively routed to the matching + interfaces.</para> <para>Note that <filename>/run/systemd/resolve/resolv.conf</filename> should not @@ -82,6 +144,7 @@ <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> </para> |