1 .TH SLAPD-LDAP 5 "RELEASEDATE" "OpenLDAP LDVERSION"
2 .\" Copyright 1998-2006 The OpenLDAP Foundation All Rights Reserved.
3 .\" Copying restrictions apply. See COPYRIGHT/LICENSE.
6 slapd-ldap \- LDAP backend to slapd
12 is not an actual database; instead it acts as a proxy to forward incoming
13 requests to another LDAP server. While processing requests it will also
14 chase referrals, so that referrals are fully processed instead of being
15 returned to the slapd client.
17 Sessions that explicitly Bind to the back-ldap database always create their
18 own private connection to the remote LDAP server. Anonymous sessions will
19 share a single anonymous connection to the remote server. For sessions bound
20 through other mechanisms, all sessions with the same DN will share the
21 same connection. This connection pooling strategy can enhance the proxy's
22 efficiency by reducing the overhead of repeatedly making/breaking multiple
25 The ldap database can also act as an information service, i.e. the identity
26 of locally authenticated clients is asserted to the remote server, possibly
27 in some modified form.
28 For this purpose, the proxy binds to the remote server with some
29 administrative identity, and, if required, authorizes the asserted identity.
33 The administrative identity of the proxy, on the remote server, must be
34 allowed to authorize by means of appropriate
41 Note: When looping back to the same instance of \fBslapd\fP(8),
42 each connection requires a new thread; as a consequence, \fBslapd\fP(8)
43 must be compiled with thread support, and the \fBthreads\fP parameter
44 may need some tuning; in those cases, one may consider using
45 \fBslapd-relay\fP(5) instead, which performs the relayed operation
46 internally and thus reuses the same connection.
51 options apply to the LDAP backend database.
52 That is, they must follow a "database ldap" line and come before any
53 subsequent "backend" or "database" lines.
54 Other database options are described in the
59 Note: In early versions of back-ldap it was recommended to always set
72 This is because operational attributes related to entry creation and
73 modification should not be proxied, as they could be mistakenly written
74 to the target server(s), generating an error.
75 The current implementation automatically sets lastmod to off, so its use
76 is redundant and should be omitted, because the lastmod directive will
77 be deprecated in the future.
81 LDAP server to use. Multiple URIs can be set in in a single
83 argument, resulting in the underlying library automatically
84 call the first server of the list that responds, e.g.
86 \fBuri "ldap://host/ ldap://backup-host/"\fP
88 The URI list is space- or comma-separated.
89 .\"This statement is mandatory.
91 .\".B server <hostport>
92 .\"Obsolete option; same as `uri ldap://<hostport>/'.
96 .B bindmethod=simple|sasl [binddn=<simple DN>] [credentials=<simple password>]
97 .B [saslmech=<SASL mech>] [secprops=<properties>] [realm=<realm>]
98 .B [authcId=<authentication ID>] [authzId=<authorization ID>]
100 Allows to define the parameters of the authentication method that is
101 internally used by the proxy to collect info related to access control.
102 The identity defined by this directive, according to the properties
103 associated to the authentication method, is supposed to have read access
104 on the target server to attributes used on the proxy for ACL checking.
105 There is no risk of giving away such values; they are only used to
107 The default is to use
109 bind, with empty \fIbinddn\fP and \fIcredentials\fP,
110 which means that the related operations will be performed anonymously.
112 .B This identity is by no means implicitly used by the proxy
113 .B when the client connects anonymously.
116 feature, instead, in some cases can be crafted to implement that behavior,
117 which is \fIintrinsically unsafe and should be used with extreme care\fP.
118 This directive obsoletes
125 .B cancel {ABANDON|ignore|exop[-discover]}
126 Defines how to handle operation cancellation.
129 is invoked, so the operation is abandoned immediately.
132 no action is taken and any further response is ignored; this may result
133 in further response messages to be queued for that connection, so it is
134 recommended that long lasting connections are timed out either by
138 so that resources eventually get released.
143 operation (RFC 3909) is issued, resulting in the cancellation
144 of the current operation; the
146 operation waits for remote server response, so its use
147 may not be recommended.
152 extended operation is detected by reading the remote server's root DSE.
155 .B chase-referrals {YES|no}
156 enable/disable automatic referral chasing, which is delegated to the
157 underlying libldap, with rebinding eventually performed if the
158 \fBrebind-as-user\fP directive is used. The default is to chase referrals.
162 This directive causes a cached connection to be dropped an recreated
163 after a given ttl, regardless of being idle or not.
166 .B idassert-authzFrom <authz-regexp>
167 if defined, selects what
169 identities are authorized to exploit the identity assertion feature.
172 follows the rules defined for the
179 for details on the syntax of this field.
184 .B bindmethod=none|simple|sasl [binddn=<simple DN>] [credentials=<simple password>]
185 .B [saslmech=<SASL mech>] [secprops=<properties>] [realm=<realm>]
186 .B [authcId=<authentication ID>] [authzId=<authorization ID>]
187 .B [authz={native|proxyauthz}] [mode=<mode>] [flags=<flags>]
189 Allows to define the parameters of the authentication method that is
190 internally used by the proxy to authorize connections that are
191 authenticated by other databases.
192 The identity defined by this directive, according to the properties
193 associated to the authentication method, is supposed to have auth access
194 on the target server to attributes used on the proxy for authentication
195 and authorization, and to be allowed to authorize the users.
196 This requires to have
198 privileges on a wide set of DNs, e.g.
199 .BR authzTo=dn.subtree:"" ,
200 and the remote server to have
208 for details on these statements and for remarks and drawbacks about
210 The supported bindmethods are
212 \fBnone|simple|sasl\fP
216 is the default, i.e. no \fIidentity assertion\fP is performed.
218 The authz parameter is used to instruct the SASL bind to exploit
220 SASL authorization, if available; since connections are cached,
221 this should only be used when authorizing with a fixed identity
222 (e.g. by means of the
227 Otherwise, the default
229 is used, i.e. the proxyAuthz control is added to all operations.
231 The supported modes are:
233 \fB<mode> := {legacy|anonymous|none|self}\fP
239 is given, the proxy always authorizes that identity.
240 .B <authorization ID>
247 The former is supposed to be expanded by the remote server according
248 to the authz rules; see
251 In the latter case, whether or not the
253 prefix is present, the string must pass DN validation and normalization.
257 which implies that the proxy will either perform a simple bind as the
259 or a SASL bind as the
261 and assert the client's identity when it is not anonymous.
262 Direct binds are always proxied.
263 The other modes imply that the proxy will always either perform a simple bind
266 or a SASL bind as the
269 .BR idassert-authzFrom
270 rules (see below), in which case the operation will fail;
271 eventually, it will assert some other identity according to
273 Other identity assertion modes are
277 which respectively mean that the
284 which means that no proxyAuthz control will be used, so the
288 identity will be asserted.
289 For all modes that require the use of the
291 control, on the remote server the proxy identity must have appropriate
293 permissions, or the asserted identities must have appropriate
295 permissions. Note, however, that the ID assertion feature is mostly
296 useful when the asserted identities do not exist on the remote server.
300 \fBoverride,{prescriptive|non-prescriptive}\fP
304 flag is used, identity assertion takes place even when the database
305 is authorizing for the identity of the client, i.e. after binding
306 with the provided identity, and thus authenticating it, the proxy
307 performs the identity assertion using the configured identity and
308 authentication method.
312 flag is used (the default), operations fail with
313 \fIinappropriateAuthentication\fP
314 for those identities whose assertion is not allowed by the
315 .B idassert-authzFrom
319 flag is used, operations are performed anonymously for those identities
320 whose assertion is not allowed by the
321 .B idassert-authzFrom
324 This directive obsoletes
325 .BR idassert-authcDN ,
326 .BR idassert-passwd ,
329 .BR idassert-method .
333 .B idle-timeout <time>
334 This directive causes a cached connection to be dropped an recreated
335 after it has been idle for the specified time.
338 .B protocol\-version {0,2,3}
339 This directive indicates what protocol version must be used to contact
341 If set to 0 (the default), the proxy uses the same protocol version
342 used by the client, otherwise the requested protocol is used.
343 The proxy returns \fIunwillingToPerform\fP if an operation that is
344 incompatible with the requested protocol is attempted.
347 .B single\-conn {NO|yes}
348 Discards current cached connection when the client rebinds.
351 .B proxy\-whoami {NO|yes}
352 Turns on proxying of the WhoAmI extended operation. If this option is
353 given, back-ldap will replace slapd's original WhoAmI routine with its
354 own. On slapd sessions that were authenticated by back-ldap, the WhoAmI
355 request will be forwarded to the remote LDAP server. Other sessions will
356 be handled by the local slapd, as before. This option is mainly useful
357 in conjunction with Proxy Authorization.
360 .B rebind-as-user {NO|yes}
361 If this option is given, the client's bind credentials are remembered
362 for rebinds when chasing referrals. Useful when
363 \fBchase-referrals\fP is set to \fByes\fP, useless otherwise.
366 .B t-f-support {NO|yes|discover}
367 enable if the remote server supports absolute filters
368 (see \fIdraft-zeilenga-ldap-t-f\fP for details).
371 support is detected by reading the remote server's root DSE.
374 .B timeout [{add|delete|modify|modrdn}=]<val> [...]
375 This directive allows to set per-operation timeouts.
376 If no operation is specified, it affects all.
377 Currently, only write operations are addressed, because searches
378 can already be limited by means of the
382 for details), and other operations are not supposed to incur into the
384 Note: if the timelimit is exceeded, the operation is abandoned;
385 the protocol does not provide any means to rollback the operation,
386 so the client will not know if the operation eventually succeeded or not.
389 .B tls {[try-]start|[try-]propagate}
390 execute the StartTLS extended operation when the connection is initialized;
391 only works if the URI directive protocol scheme is not \fBldaps://\fP.
392 \fBpropagate\fP issues the StartTLS operation only if the original
394 The \fBtry-\fP prefix instructs the proxy to continue operations
395 if the StartTLS operation failed; its use is highly deprecated.
397 .SH BACKWARD COMPATIBILITY
398 The LDAP backend has been heavily reworked between releases 2.2 and 2.3;
399 as a side-effect, some of the traditional directives have been
400 deprecated and should be no longer used, as they might disappear
404 .B server <hostname[:port]>
405 this directive is no longer supported. Use the
407 directive as described above.
410 .B acl-authcDN "<administrative DN for access control purposes>"
411 DN which is used to query the target server for acl checking; it
412 is supposed to have read access on the target server to attributes used
413 on the proxy for acl checking.
414 There is no risk of giving away such values; they are only used to
416 .B The acl-authcDN identity is by no means implicitly used by the proxy
417 .B when the client connects anonymously.
421 This directive is obsoleted by the
425 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
428 .B acl-passwd <password>
429 Password used with the above
432 This directive is obsoleted by the
436 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
439 .B idassert-authcDN "<administrative DN for proxyAuthz purposes>"
440 DN which is used to propagate the client's identity to the target
441 by means of the proxyAuthz control when the client does not
442 belong to the DIT fragment that is being proxied by back-ldap.
443 This directive is obsoleted by the
447 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
450 .B idassert-passwd <password>
451 Password used with the
454 This directive is obsoleted by the
458 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
461 .B idassert-mode <mode> [<flags>]
463 .I identity assertion
465 This directive is obsoleted by the
469 and will be dismissed in the future.
472 .B idassert-method <method> [<saslargs>]
473 This directive is obsoleted by the
477 and will be dismissed in the future.
480 .B suffixmassage, map, rewrite*
481 These directives are no longer supported by back-ldap; their
482 functionality is now delegated to the
484 overlay. Essentially, add a statement
488 first, and prefix all rewrite/map statements with
490 to obtain the original behavior.
494 .\" However, to ease update from existing configurations, back-ldap still
495 .\" recognizes them and automatically instantiates the
497 .\" overlay if available and not instantiated yet.
498 .\" This behavior may change in the future.
503 backend does not honor all ACL semantics as described in
504 .BR slapd.access (5).
505 In general, access checking is delegated to the remote server(s).
510 pseudo-attribute and to the other attribute values of the entries
513 operation is honored, which is performed by the frontend.
516 The LDAP backend provides basic proxying functionalities to many overlays.
519 overlay, described in
520 .BR slapo\-chain (5),
523 overlay, described in
524 .BR slapo\-translucent (5),
525 deserve a special mention.
527 Conversely, there are many overlays that are best used in conjunction
528 with the LDAP backend.
531 overlay allows caching of LDAP search requests (queries)
534 .BR slapo\-pcache (5)
538 overlay provides DN rewrite and attribute/objectClass mapping
539 capabilities to the underlying database.
547 default slapd configuration file
551 .BR slapo\-chain (5),
552 .BR slapo\-pcache (5),
554 .BR slapo\-translucent (5),
558 Howard Chu, with enhancements by Pierangelo Masarati
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