NSCD(8) Linux Programmer's Manual NSCD(8)
/usr/sbin/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. See nscd.conf(5).
Nscd provides cacheing for accesses of the passwd(5), group(5), and
hosts(5) databases through standard libc interfaces, such as getpw-
nam(3), getpwuid(3), getgrnam(3), getgrgid(3), gethostbyname(3), and
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. As a result of this behavior there is not possible to change
non-nscd user to another non-nscd user via su service when nscd is run-
--help will give you a list with all options and what they do.
Nscd doesn't know anything about the underlaying protocols for a ser-
vice. This also means, that if you change /etc/resolv.conf for DNS
queries, nscd will continue to use the old one if you have configured
/etc/nsswitch.conf to use DNS for host lookups. In such a case, you
need to restart nscd.
nscd was written by Thorsten Kukuk and Ulrich Drepper.
GNU C Library 1999-10 NSCD(8)