nss-myhostname, libnss_myhostname.so.2 - Provide hostname resolution for the
locally configured system hostname.
is a plug-in module for the GNU Name Service Switch (NSS)
functionality of the GNU C Library ( glibc
), primarily providing
hostname resolution for the locally configured system hostname as returned by
(2). The precise hostnames resolved by this module are:
•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
•The hostnames "localhost"
and "localhost.localdomain" (as well as any hostname ending in
".localhost" or ".localhost.localdomain") are resolved to
the IP addresses 127.0.0.1 and ::1.
•The hostname "gateway" 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.
Various software relies on an always-resolvable local hostname. When using
dynamic hostnames, this is traditionally achieved by patching /etc/hosts at
the same time as changing the hostname. This is problematic since it requires
a writable /etc file system and is fragile because the file might be edited by
the administrator at the same time. With nss-myhostname
changing /etc/hosts is unnecessary, and on many systems, the file becomes
To activate the NSS modules, add "myhostname" to the line starting
with "hosts:" in /etc/nsswitch.conf.
It is recommended to place "myhostname" last in the nsswitch.conf'
"hosts:" line to make sure that this mapping is only used as
fallback, and that any DNS or /etc/hosts based mapping takes precedence.
Here is an example /etc/nsswitch.conf file that enables nss-myhostname
passwd: compat mymachines systemd
group: compat mymachines systemd
hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname
protocols: db files
services: db files
ethers: db files
rpc: db files
To test, use glibc
$ getent ahosts `hostname`
::1 STREAM omega
In this case, the local hostname is omega