+++ /dev/null
-<?xml version='1.0'?> <!--*-nxml-*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
-<!--
- This file is part of systemd.
-
- Copyright 2011 Lennart Poettering
- Copyright 2013 Tom Gundersen
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
-
-<refentry id="nss-myhostname" conditional='HAVE_MYHOSTNAME'>
-
- <refentryinfo>
- <title>nss-myhostname</title>
- <productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
- </refentryinfo>
-
- <refmeta>
- <refentrytitle>nss-myhostname</refentrytitle>
- <manvolnum>8</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>nss-myhostname</refname>
- <refname>libnss_myhostname.so.2</refname>
- <refpurpose>Provide hostname resolution for the locally
- configured system hostname.</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <para><filename>libnss_myhostname.so.2</filename></para>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para><command>nss-myhostname</command> is a plugin for the GNU
- Name Service Switch (NSS) functionality of the GNU C Library
- (<command>glibc</command>) primarily providing hostname resolution
- for the locally configured system hostname as returned by
- <citerefentry><refentrytitle>gethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
- The precise hostnames resolved by this module are:</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>Various software relies on an always-resolvable local
- hostname. When using dynamic hostnames, this is traditionally
- achieved by patching <filename>/etc/hosts</filename> at the same
- time as changing the hostname. This is problematic since it
- requires a writable <filename>/etc</filename> file system and is
- fragile because the file might be edited by the administrator at
- the same time. With <command>nss-myhostname</command> enabled
- changing <filename>/etc/hosts</filename> is unncessary, and on
- many systems the file becomes entirely optional.</para>
-
- <para>To activate the NSS modules, <literal>myhostname</literal>
- has to be added to the line starting with
- <literal>hosts:</literal> in
- <filename>/etc/nsswitch.conf</filename>.</para>
-
- <para>It is recommended to place <literal>myhostname</literal>
- last in the <filename>nsswitch.conf</filename> line to make sure
- that this mapping is only used as fallback, and any DNS or
- <filename>/etc/hosts</filename> based mapping takes
- precedence.</para>
- </refsect1>
-
- <refsect1>
- <title>Example</title>
-
- <para>Here's an example <filename>/etc/nsswitch.conf</filename>
- file, that enables <command>myhostname</command> correctly:</para>
-
-<programlisting>passwd: compat
-group: compat
-shadow: compat
-
-hosts: files dns mymachines <command>myhostname</command>
-networks: files
-
-protocols: db files
-services: db files
-ethers: db files
-rpc: db files
-
-netgroup: nis</programlisting>
-
- <para>To test, use <command>glibc</command>'s <command>getent</command> tool:</para>
-
- <programlisting>$ getent ahosts `hostname`
-::1 STREAM omega
-::1 DGRAM
-::1 RAW
-127.0.0.2 STREAM
-127.0.0.2 DGRAM
-127.0.0.2 RAW</programlisting>
-
- <para>In this case the local hostname is <varname>omega</varname>.</para>
-
- </refsect1>
-
- <refsect1>
- <title>See Also</title>
- <para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>nss-mymachines</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry project='man-pages'><refentrytitle>nsswitch.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry project='man-pages'><refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- </para>
- </refsect1>
-
-</refentry>
~ianmdlvl / elogind.git / blobdiff