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NSS-MYHOSTNAME(8) | nss-myhostname | NSS-MYHOSTNAME(8) |
NAME¶
nss-myhostname, libnss_myhostname.so.2 - Provide hostname resolution for the locally configured system hostname.SYNOPSIS¶
libnss_myhostname.so.2DESCRIPTION¶
nss-myhostname 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 gethostname(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 host).
•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 enabled,
changing /etc/hosts is unnecessary, and on many systems, the file becomes
entirely optional.
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.
EXAMPLE¶
Here is an example /etc/nsswitch.conf file that enables nss-myhostname correctly:passwd: compat mymachines group: compat mymachines shadow: compat hosts: files mymachines resolve myhostname networks: files protocols: db files services: db files ethers: db files rpc: db files netgroup: nis
$ 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
SEE ALSO¶
systemd(1), nss-resolve(8), nss-mymachines(8), nsswitch.conf(5), getent(1)systemd 230 |