NSCD(8) Linux Programmer's Manual NSCD(8)
nscd - name service cache daemon
Nscd is a daemon that provides a cache for the most common name service requests. The
default configuration file, /etc/nscd.conf, determines the behavior of the cache daemon.
Nscd provides caching for accesses of the passwd(5), group(5), and hosts(5) databases
through standard libc interfaces, such as getpwnam(3), getpwuid(3), getgrnam(3), get-
grgid(3), gethostbyname(3), and others.
There are two caches for each database: a positive one for items found, and a negative one
for items not found. Each cache has a separate TTL (time-to-live) period for its data.
Note that the shadow file is specifically not cached. getspnam(3) calls remain uncached
as a result.
--help will give you a list with all options and what they do.
The daemon will try to watch for changes in configuration files appropriate for each data-
base (e.g., /etc/passwd for the passwd database or /etc/hosts and /etc/resolv.conf for the
hosts database), and flush the cache when these are changed. However, this will happen
only after a short delay (unless the inotify(7) mechanism is available and glibc 2.9 or
later is available), and this auto-detection does not cover configuration files required
by nonstandard NSS modules, if any are specified in /etc/nsswitch.conf. In that case, you
need to run the following command after changing the configuration file of the database so
that nscd invalidates its cache:
$ nscd -i <database>
This page is part of release 3.55 of the Linux man-pages project. A description of the
project, and information about reporting bugs, can be found at
GNU 2012-05-10 NSCD(8)