<?xml version='1.0'?>
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
-<!--
- SPDX-License-Identifier: LGPL-2.1+
--->
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="nss-resolve" conditional='ENABLE_NSS_RESOLVE'>
<title>Description</title>
<para><command>nss-resolve</command> is a plug-in module for the GNU Name Service Switch (NSS) functionality of the
- GNU C Library (<command>glibc</command>) enabling it to resolve host names via the
+ GNU C Library (<command>glibc</command>) enabling it to resolve hostnames via the
<citerefentry><refentrytitle>systemd-resolved</refentrytitle><manvolnum>8</manvolnum></citerefentry> local network
name resolution service. It replaces the <command>nss-dns</command> plug-in module that traditionally resolves
hostnames via DNS.</para>
- <para>To activate the NSS module, add <literal>resolve</literal> to the line starting with
- <literal>hosts:</literal> in <filename>/etc/nsswitch.conf</filename>. Specifically, it is recommended to place
- <literal>resolve</literal> early in <filename>/etc/nsswitch.conf</filename>'s <literal>hosts:</literal> line (but
- after the <literal>files</literal> or <literal>mymachines</literal> entries), right before the
- <literal>dns</literal> entry if it exists, followed by <literal>[!UNAVAIL=return]</literal>, to ensure DNS queries
- are always routed via
- <citerefentry><refentrytitle>systemd-resolved</refentrytitle><manvolnum>8</manvolnum></citerefentry> if it is
- running, but are routed to <command>nss-dns</command> if this service is not available.</para>
+ <para>To activate the NSS module, add <literal>resolveĀ [!UNAVAIL=return]</literal> to the line starting
+ with <literal>hosts:</literal> in <filename>/etc/nsswitch.conf</filename>. Specifically, it is
+ recommended to place <literal>resolve</literal> early in <filename>/etc/nsswitch.conf</filename>'s
+ <literal>hosts:</literal> line. It should be before the <literal>files</literal> entry, since
+ <filename>systemd-resolved</filename> supports <filename>/etc/hosts</filename> internally, but with
+ caching. To the contrary, it should be after <literal>mymachines</literal>, to give hostnames given to
+ local VMs and containers precedence over names received over DNS. Finally, we recommend placing
+ <literal>dns</literal> somewhere after <literal>resolve</literal>, to fall back to
+ <command>nss-dns</command> if <filename>systemd-resolved.service</filename> is not available.</para>
<para>Note that <command>systemd-resolved</command> will synthesize DNS resource
records in a few cases, for example for <literal>localhost</literal> and the
<para>Here is an example <filename>/etc/nsswitch.conf</filename> file that enables <command>nss-resolve</command>
correctly:</para>
+ <!-- synchronize with other nss-* man pages and factory/etc/nsswitch.conf -->
<programlisting>passwd: compat mymachines systemd
group: compat mymachines systemd
shadow: compat
-hosts: files mymachines <command>resolve [!UNAVAIL=return]</command> dns myhostname
+hosts: mymachines <command>resolve [!UNAVAIL=return]</command> myhostname files dns
networks: files
protocols: db files