nscd(8) -- Linux man page
NAME/usr/sbin/nscd - name service cache daemon
DESCRIPTIONNscd 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 the passwd(5), group(5), and hosts(5) databases through standard libc interfaces, such as getpwnam(3), getpwuid(3), getgrnam(3), getgrgid(3), gethostbyname(3), and others. Each cache has a separate TTL (time-to-live) for its data; modifying the local database (/etc/passwd, and so forth) causes the cache to become invalidated within fifteen seconds. Note that the shadow file is specifically not cached. getspnam(3) calls remain uncached as a result.
will give you a list with all options and what they do.
NOTESNscd doesn't know anything about the underlaying protocols for a service. 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.
SEE ALSOnscd.conf(5), nsswitch.conf(5)
AUTHORnscd was written by Thorsten Kukuk and Ulrich Drepper.