nss-myhostname 0.3

Copyright 2005-2011 Lennart Poettering <mzzlubfganzr (at) 0pointer (dot) de>


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.

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.


Mon May 9 2011:

Version 0.3 released. Changes include: Always return locally configured IP addresses first, use only as fallback if no addresses are configured.

Mon Oct 27 2008:

Version 0.2 released. Changes include: Update for IPv6 and newest glibc NSS interfaces

Sat Nov 19 2005:

Version 0.1 released. Initial release.


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

Current Status

It works!


After compiling and installing nss-myhostname you'll find a new NSS modules in /lib:

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

# /etc/nsswitch.conf

passwd:         compat
group:          compat
shadow:         compat

hosts:          files dns myhostname
networks:       files

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

netgroup:       nis

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

$ getent ahosts `hostname`
::1             STREAM omega
::1             DGRAM
::1             RAW       STREAM       DGRAM       RAW

In this case the local host name is omega.

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


nss-myhostname uses NSS interfaces that are specific to modern glibc's.

nss-myhostname 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.


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


None so far.


The newest release is always available from http://0pointer.de/lennart/projects/nss-myhostname/

The current release is 0.3

Get nss-myhostname's development sources from the GIT repository (gitweb):

git clone git://git.0pointer.de/nss-myhostname

Lennart Poettering <mzzlubfganzr (at) 0pointer (dot) de>, May 2011