man8/nscd.8

   1 .\" Copyright 1999 SuSE GmbH Nuernberg, Germany
   2 .\" Author: Thorsten Kukuk <kukuk@suse.de>
   3 .\"
   4 .\" %%%LICENSE_START(GPLv2+_SW_3_PARA)
   5 .\" This program is free software; you can redistribute it and/or
   6 .\" modify it under the terms of the GNU General Public License as
   7 .\" published by the Free Software Foundation; either version 2 of the
   8 .\" License, or (at your option) any later version.
   9 .\"
  10 .\" This program is distributed in the hope that it will be useful,
  11 .\" but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 .\" General Public License for more details.
  14 .\"
  15 .\" You should have received a copy of the GNU General Public
  16 .\" License along with this manual; if not, see
  17 .\" <http://www.gnu.org/licenses/>.
  18 .\" %%%LICENSE_END
  19 .\"
  20 .\" 2008-12-05 Petr Baudis <pasky@suse.cz>
  21 .\"     Rewrite the NOTES section to reflect modern reality
  22 .\"
  23 .TH NSCD 8 2015-05-07 "GNU" "Linux Programmer's Manual"
  24 .SH NAME
  25 nscd \- name service cache daemon
  26 .SH DESCRIPTION
  27 .B nscd
  28 is a daemon that provides a cache for the most common name service
  29 requests.
  30 The default configuration file,
  31 .IR /etc/nscd.conf ,
  32 determines the behavior of the cache daemon.
  33 See
  34 .BR nscd.conf (5).
  35 .PP
  36 .B nscd
  37 provides caching for accesses of the
  38 .BR passwd (5),
  39 .BR group (5),
  40 .BR hosts (5)
  41 .BR services (5)
  42 and
  43 .I netgroup
  44 databases through standard libc interfaces, such as
  45 .BR getpwnam (3),
  46 .BR getpwuid (3),
  47 .BR getgrnam (3),
  48 .BR getgrgid (3),
  49 .BR gethostbyname (3),
  50 and others.
  51 .PP
  52 There are two caches for each database:
  53 a positive one for items found, and a negative one
  54 for items not found.
  55 Each cache has a separate TTL (time-to-live)
  56 period for its data.
  57 Note that the shadow file is specifically not cached.
  58 .BR getspnam (3)
  59 calls remain uncached as a result.
  60 .SH OPTIONS
  61 .TP
  62 .B "\-\-help"
  63 will give you a list with all options and what they do.
  64 .SH NOTES
  65 The daemon will try to watch for changes in configuration files
  66 appropriate for each database (e.g.,
  67 .I /etc/passwd
  68 for the
  69 .I passwd
  70 database or
  71 .I /etc/hosts
  72 and
  73 .I /etc/resolv.conf
  74 for the
  75 .I hosts
  76 database), and flush the cache when these are changed.
  77 However, this will happen only after a short delay (unless the
  78 .BR inotify (7)
  79 mechanism is available and glibc 2.9 or later is available),
  80 and this auto-detection does not cover configuration files
  81 required by nonstandard NSS modules, if any are specified in
  82 .IR /etc/nsswitch.conf .
  83 In that case, you need to run the following command
  84 after changing the configuration file of the database so that
  85 .B nscd
  86 invalidates its cache:
  87 .PP
  88 .in +4n
  89 .EX
  90 $ \fBnscd -i\fP \fI<database>\fP
  91 .EE
  92 .in
  93 .SH SEE ALSO
  94 .BR nscd.conf (5),
  95 .BR nsswitch.conf (5)
  96 .\" .SH AUTHOR
  97 .\" .B nscd
  98 .\" was written by Thorsten Kukuk and Ulrich Drepper.