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

<p><i>Copyright 2005-2008 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 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>. A lot of software relies on that the
local host name is resolvable via DNS to an IPv4 or IPv6 address. When
using dynamic hostnames this is usually achieved by
patching <tt>/etc/hosts</tt> which however is suboptimal since it
requires a writable <tt>/etc</tt> file system and is fragile because
the file might also be edited by the
administrator. <tt>nss-myhostname</tt> simply returns 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/hostname</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 10
from October 2008, 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;, October 2008</address>

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