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 caching for accesses of the passwd(5), group(5), hosts(5) service(5) and netgroup databases through standard libc interfaces, such as getpwnam(3), getpwuid(3), getgrnam(3), getgrgid(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.
The daemon will try to watch for changes in configuration
files appropriate for each database (e.g.,
/etc/passwd for the passwd database or
/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
$ nscd -i
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Copyright 1999 SuSE GmbH Nuernberg, Germany
Author: Thorsten Kukuk <kukuksuse.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public
License along with this manual; if not, see
2008-12-05 Petr Baudis <paskysuse.cz>
Rewrite the NOTES section to reflect modern reality