nss-myhostname — Provide host name resolution for the locally configured system hostname.
nss-myhostname.la
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 127.0.0.2 (which 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.
To activate the NSS modules, myhostname
                has to be added to the line starting with "hosts:" in
                /etc/nsswitch.conf
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.
# /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
                To test, use glibc's getent tool:
$ 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
                In this case the local host name is omega.