1 .\" $NetBSD: nsswitch.conf.5,v 1.14 1999/03/17 20:19:47 garbled Exp $
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41 .Nd name-service switch configuration file
45 file specifies how the
47 (name-service switch dispatcher) routines in the C library should operate.
49 The configuration file controls how a process looks up various databases
50 containing information regarding hosts, users (passwords), groups, etc.
51 Each database comes from a source (such as local files, DNS,
53 and cache), and the order to look up the sources is specified in
58 consists of a database name, and a space separated list of sources.
59 Each source can have an optional trailing criterion that determines
60 whether the next listed source is used, or the search terminates at
62 Each criterion consists of one or more status codes, and actions to
63 take if that status code occurs.
65 The following sources are implemented:
67 .Bl -tag -width Source -compact
78 Internet Domain Name System.
84 class entries, all other databases use
86 class (Hesiod) entries.
97 If this is present, it must be the only source for that entry.
104 The following databases are used by the following C library functions:
106 .Bl -tag -width networks -compact
118 .Xr gethostbyaddr 3 ,
119 .Xr gethostbyaddr_r 3 ,
120 .Xr gethostbyname 3 ,
121 .Xr gethostbyname2 3 ,
122 .Xr gethostbyname_r 3 ,
123 .Xr getipnodebyaddr 3 ,
124 .Xr getipnodebyname 3
127 .Xr getnetbyaddr_r 3 ,
143 .Xr getrpcbynumber 3 ,
146 .Xr getprotobyname 3 ,
147 .Xr getprotobynumber 3 ,
151 .Xr getnetgrent_r 3 ,
157 The following status codes are available:
159 .Bl -tag -width tryagain -compact
163 The requested entry was found.
165 The entry is not present at this source.
167 The source is busy, and may respond to retries.
169 The source is not responding, or entry is corrupt.
172 For each of the status codes, one of two actions is possible:
174 .Bl -tag -width continue -compact
180 Return with the current result
185 description of the syntax of
189 .Bl -tag -width <criterion> -compact
192 <database> ":" [<source> [<criteria>]]*
198 <status> "=" <action>
201 "success" | "notfound" | "unavail" | "tryagain"
204 "return" | "continue"
207 Each entry starts on a new line in the file.
210 delimits a comment to end of line.
211 Blank lines are ignored.
214 at the end of a line escapes the newline, and causes the next line to
215 be a continuation of the current line.
216 All entries are case-insensitive.
218 The default criteria is to return on
220 and continue on anything else (i.e,
221 .Li "[success=return notfound=continue unavail=continue tryagain=continue]" ) .
223 You can enable caching for the particular database by specifying
225 as the first source in the
228 You should also enable caching for this database in
230 If for the particular query
232 source returns success, no further sources are queried.
233 On the other hand, if there are no previously cached data, the
234 query result will be placed into the cache right after
235 all other sources are processed.
240 daemon to be running.
241 .Ss Compat mode: +/- syntax
242 In historical multi-source implementations, the
246 characters are used to specify the importing of user password and
247 group information from
251 provides alternative methods of accessing distributed sources such as
253 specifying a sole source of
255 will provide the historical behaviour.
257 An alternative source for the information accessed via
259 can be used by specifying
260 .Dq passwd_compat: source .
266 any other source except for
271 Historically, many of the databases had enumeration functions, often of
274 These made sense when the databases were in local files, but do not make
275 sense or have lesser relevance when there are possibly multiple sources,
276 each of an unknown size.
277 The interfaces are still provided for compatibility, but the source
278 may not be able to provide complete entries, or duplicate entries may
279 be retrieved if multiple sources that contain similar information are
282 To ensure compatibility with previous and current implementations, the
284 source must appear alone for a given database.
285 .Ss Default source lists
288 does not exist, or it has missing or corrupt entries,
290 will default to an entry of
292 for the requested database.
295 .Bl -tag -width services_compat -compact
297 .Sy "Default source list"
314 .Bl -tag -width /etc/nsswitch.conf -compact
315 .It Pa /etc/nsswitch.conf
322 To lookup hosts in cache, then in
324 and then from the DNS, and lookup user information from
328 .Bl -tag -width passwd: -compact
332 nis [notfound=return] files
334 nis [notfound=return] files
338 .Dq [notfound=return]
339 sets a policy of "if the user is notfound in nis, do not try files."
340 This treats nis as the authoritative source of information, except
341 when the server is down.
343 If system got compiled with
351 provides stubs for compatibility with NSS modules
357 However, these stubs only support the use of the
371 file format first appeared in
373 It was imported from the
375 Project, where it appeared first in
378 .An Luke Mewburn Aq Mt lukem@netbsd.org
379 wrote this freely distributable name-service switch implementation,