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<h1><a name="top">nss-myhostname @PACKAGE_VERSION@</a></h1>

<p><i>Copyright 2005-2011 Lennart Poettering &lt;@PACKAGE_BUGREPORT@&gt;</i></p>

<ul class="toc">
    <li><a href="#license">License</a></li>
    <li><a href="#news">News</a></li>
    <li><a href="#overview">Overview</a></li>
    <li><a href="#status">Current Status</a></li>
    <li><a href="#documentation">Documentation</a></li>
    <li><a href="#requirements">Requirements</a></li>
    <li><a href="#installation">Installation</a></li>
    <li><a href="#acks">Acknowledgements</a></li>
    <li><a href="#download">Download</a></li>
</ul>

<h2><a name="license">License</a></h2>

<p>This program 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.</p>

<p>This program 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.</p>

<h2><a name="news">News</a></h2>

<div class="news-date">Mon May 9 2011: </div>

<p class="news-text"><a href="@PACKAGE_URL@nss-myhostname-0.3.tar.gz">Version
0.3</a> released. Changes include: Always return locally configured IP
addresses first, use 127.0.0.2/::1 only as fallback if no addresses
are configured.</p>

<div class="news-date">Mon Oct 27 2008: </div>

<p class="news-text"><a
href="@PACKAGE_URL@nss-myhostname-0.2.tar.gz">Version 0.2</a>
released. Changes include: Update for IPv6 and newest glibc NSS interfaces</p>

<div class="news-date">Sat Nov 19 2005: </div>

<p class="news-text"><a
href="@PACKAGE_URL@nss-myhostname-0.1.tar.gz">Version 0.1</a>
released. Initial release.</p>

<h2><a name="overview">Overview</a></h2>

<p><tt>nss-myhostname</tt> is a plugin for the GNU Name Service Switch
(NSS) functionality of the GNU C Library (<tt>glibc</tt>) providing
host name resolution for the locally configured system hostname as
returned by <tt>gethostname(2)</tt>. Various software relies on an
always resolvable local host name. When using dynamic hostnames this
is usually achieved by patching <tt>/etc/hosts</tt> at the same time
as changing the host name. This however is not ideal since it requires
a writable <tt>/etc</tt> file system and is fragile because the file
might be edited by the administrator at the same
time. <tt>nss-myhostname</tt> simply returns all locally configure
public IP addresses, or -- if none are configured -- the IPv4
address <tt>127.0.0.2</tt> (wich is on the local loopback) and the
IPv6 address <tt>::1</tt> (which is the local host) for whatever
system hostname is configured locally. Patching <tt>/etc/hosts</tt>
is thus no longer necessary.</p>

<h2><a name="status">Current Status</a></h2>

<p>It works!</p>

<h2><a name="documentation">Documentation</a></h2>

<p>After compiling and installing <tt>nss-myhostname</tt> you'll find a
new NSS modules in <tt>/lib</tt>:</p>
<ul>
<li><tt>libnss_myhostname.so.2</tt></li>
</ul>

<p>To activate the NSS modules you have to edit
<tt>/etc/nsswitch.conf</tt> and add <tt>myhostname</tt> to the
line starting with "<tt>hosts:</tt>". On Debian this looks like
this:</p>

<pre># /etc/nsswitch.conf

passwd:         compat
group:          compat
shadow:         compat

hosts:          files dns <b>myhostname</b>
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis</pre>

<p>That's it. You should now always be able to resolve your local
system hostname. For a quick check
use <tt>glibc</tt>'s <tt>getent</tt> tool:

<pre>$ 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
</pre>

<p>In this case the local host name is <i>omega</i>.</p>

<p>It is recommended to put <tt>myhostname</tt> last in
the <tt>nsswitch.conf</tt> line to make sure that this mapping is only
used as fallback, and any DNS or <tt>/etc/hosts</tt> based mapping takes
precedence.</p>

<h2><a name="requirements">Requirements</a></h2>

<p><tt>nss-myhostname</tt> uses NSS interfaces that are specific to modern <tt>glibc</tt>'s.</p>

<p><tt>nss-myhostname</tt> was developed and tested on Fedora 15 from
May 2011, it should work on most other Linux distributions since it
uses GNU autoconf and GNU libtool for source code configuration and
shared library management.</p>

<h2><a name="installation">Installation</a></h2>

<p>As this package is made with the GNU autotools you should run
<tt>./configure</tt> inside the distribution directory for configuring
the source tree. After that you should run <tt>make</tt> for
compilation and <tt>make install</tt> (as root) for installation of
<tt>nss-myhostname</tt>.</p>

<h2><a name="acks">Acknowledgements</a></h2>

<p>None so far.</p>

<h2><a name="download">Download</a></h2>

<p>The newest release is always available from <a href="@PACKAGE_URL@">@PACKAGE_URL@</a></p>

<p>The current release is <a href="@PACKAGE_URL@nss-myhostname-@PACKAGE_VERSION@.tar.gz">@PACKAGE_VERSION@</a></p>

<p>Get <tt>nss-myhostname</tt>'s development sources from the <a href="http://git.or.cz/">GIT</a> <a href="git://git.0pointer.de/nss-myhostname">repository</a> (<a href="http://git.0pointer.de/?p=nss-myhostname.git">gitweb</a>): </p>

<pre>git clone git://git.0pointer.de/nss-myhostname</pre>

<hr/>
<address class="grey">Lennart Poettering &lt;@PACKAGE_BUGREPORT@&gt;, May 2011</address>

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