.\" $NetBSD: nsswitch.conf.5,v 1.14 1999/03/17 20:19:47 garbled Exp $ .\" .\" Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc. .\" All rights reserved. .\" .\" This code is derived from software contributed to The NetBSD Foundation .\" by Luke Mewburn. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by Luke Mewburn. .\" 4. The name of the author may not be used to endorse or promote products .\" derived from this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, .\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS .\" OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND .\" ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR .\" TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE .\" USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" $FreeBSD$ .\" .Dd June 21, 2004 .Dt NSSWITCH.CONF 5 .Os .Sh NAME .Nm nsswitch.conf .Nd name-service switch configuration file .Sh DESCRIPTION The .Nm file specifies how the .Xr nsdispatch 3 (name-service switch dispatcher) routines in the C library should operate. .Pp The configuration file controls how a process looks up various databases containing information regarding hosts, users (passwords), groups, etc. Each database comes from a source (such as local files, DNS, and .Tn NIS ) , and the order to look up the sources is specified in .Nm . .Pp Each entry in .Nm consists of a database name, and a space separated list of sources. Each source can have an optional trailing criterion that determines whether the next listed source is used, or the search terminates at the current source. Each criterion consists of one or more status codes, and actions to take if that status code occurs. .Ss Sources The following sources are implemented: .Pp .Bl -tag -width Source -compact .It Sy Source .Sy Description .It files Local files, such as .Pa /etc/hosts , and .Pa /etc/passwd . .It dns Internet Domain Name System. .Dq hosts and .Sq networks use .Sy IN class entries, all other databases use .Sy HS class (Hesiod) entries. .It nis NIS (formerly YP) .It compat support .Sq +/- in the .Dq passwd and .Dq group databases. If this is present, it must be the only source for that entry. .El .Ss Databases The following databases are used by the following C library functions: .Pp .Bl -tag -width networks -compact .It Sy Database .Sy "Used by" .It group .Xr getgrent 3 .It hosts .Xr gethostbyname 3 .It networks .Xr getnetbyname 3 .It passwd .Xr getpwent 3 .It shells .Xr getusershell 3 .El .Ss Status codes The following status codes are available: .Pp .Bl -tag -width tryagain -compact .It Sy Status .Sy Description .It success The requested entry was found. .It notfound The entry is not present at this source. .It tryagain The source is busy, and may respond to retries. .It unavail The source is not responding, or entry is corrupt. .El .Ss Actions For each of the status codes, one of two actions is possible: .Pp .Bl -tag -width continue -compact .It Sy Action .Sy Description .It continue Try the next source .It return Return with the current result .El .Ss Format of file A .Tn BNF description of the syntax of .Nm is: .Pp .Bl -tag -width -compact .It ::= ":" [ []]* .It ::= "[" + "]" .It ::= "=" .It ::= "success" | "notfound" | "unavail" | "tryagain" .It ::= "return" | "continue" .El .Pp Each entry starts on a new line in the file. A .Sq # delimits a comment to end of line. Blank lines are ignored. A .Sq \e at the end of a line escapes the newline, and causes the next line to be a continuation of the current line. All entries are case-insensitive. .Pp The default criteria is to return on .Dq success , and continue on anything else (i.e, .Li "[success=return notfound=continue unavail=continue tryagain=continue]" ) . .Ss Compat mode: +/- syntax In historical multi-source implementations, the .Sq + and .Sq - characters are used to specify the importing of user password and group information from .Tn NIS . Although .Nm provides alternative methods of accessing distributed sources such as .Tn NIS , specifying a sole source of .Dq compat will provide the historical behaviour. .Pp An alternative source for the information accessed via .Sq +/- can be used by specifying .Dq passwd_compat: source . .Dq source in this case can be .Sq dns , .Sq nis , or any other source except for .Sq files and .Sq compat . .Ss Notes Historically, many of the databases had enumeration functions, often of the form .Fn getXXXent . These made sense when the databases were in local files, but don't make sense or have lesser relevance when there are possibly multiple sources, each of an unknown size. The interfaces are still provided for compatibility, but the source may not be able to provide complete entries, or duplicate entries may be retrieved if multiple sources that contain similar information are specified. .Pp To ensure compatibility with previous and current implementations, the .Dq compat source must appear alone for a given database. .Ss Default source lists If, for any reason, .Nm doesn't exist, or it has missing or corrupt entries, .Xr nsdispatch 3 will default to an entry of .Dq files for the requested database. Exceptions are: .Pp .Bl -tag -width passwd_compat -compact .It Sy Database .Sy "Default source list" .It group compat .It group_compat nis .It hosts files dns .It passwd compat .It passwd_compat nis .El .Sh FILES .Bl -tag -width /etc/nsswitch.conf -compact .It Pa /etc/nsswitch.conf The file .Nm resides in .Pa /etc . .El .Sh EXAMPLES To lookup hosts in .Pa /etc/hosts and then from the DNS, and lookup user information from .Tn NIS then files, use: .Pp .Bl -tag -width passwd: -compact .It hosts: files dns .It passwd: nis [notfound=return] files .It group: nis [notfound=return] files .El .Pp The criteria .Dq [notfound=return] sets a policy of "if the user is notfound in nis, don't try files." This treats nis as the authoritative source of information, except when the server is down. .Sh SEE ALSO .Xr nsdispatch 3 , .Xr resolv.conf 5 , .Xr named 8 , .Xr ypbind 8 .Sh HISTORY The .Nm file format first appeared in .Fx 5.0 . It was imported from the .Nx Project, where it appeared first in .Nx 1.4 . .Sh AUTHORS Luke Mewburn .Aq lukem@netbsd.org wrote this freely distributable name-service switch implementation, using ideas from the .Tn ULTRIX .Xr svc.conf 5 and .Tn Solaris .Xr nsswitch.conf 4 manual pages.