1 .TH SLAPD-LDAP 5 "RELEASEDATE" "OpenLDAP LDVERSION"
2 .\" Copyright 1998-2008 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
43 each connection requires a new thread; as a consequence,
45 must be compiled with thread support, and the \fBthreads\fP parameter
46 may need some tuning; in those cases, one may consider using
48 instead, which performs the relayed operation
49 internally and thus reuses the same connection.
54 options apply to the LDAP backend database.
55 That is, they must follow a "database ldap" line and come before any
56 subsequent "backend" or "database" lines.
57 Other database options are described in the
62 Note: In early versions of back-ldap it was recommended to always set
75 This was required because operational attributes related to entry creation
76 and modification should not be proxied, as they could be mistakenly written
77 to the target server(s), generating an error.
78 The current implementation automatically sets lastmod to \fBoff\fP,
79 so its use is redundant and should be omitted.
83 LDAP server to use. Multiple URIs can be set in a single
85 argument, resulting in the underlying library automatically
86 call the first server of the list that responds, e.g.
88 \fBuri "ldap://host/ ldap://backup-host/"\fP
90 The URI list is space- or comma-separated.
91 Whenever the server that responds is not the first one in the list,
92 the list is rearranged and the responsive server is moved to the head,
93 so that it will be first contacted the next time a connection
98 .B bindmethod=simple|sasl [binddn=<simple DN>] [credentials=<simple password>]
99 .B [saslmech=<SASL mech>] [secprops=<properties>] [realm=<realm>]
100 .B [authcId=<authentication ID>] [authzId=<authorization ID>]
103 .B [tls_cacert=<file>]
104 .B [tls_cacertdir=<path>]
105 .B [tls_reqcert=never|allow|try|demand]
106 .B [tls_ciphersuite=<ciphers>]
107 .B [tls_crlcheck=none|peer|all]
109 Allows to define the parameters of the authentication method that is
110 internally used by the proxy to collect info related to access control,
111 and whenever an operation occurs with the identity of the rootdn
112 of the LDAP proxy database.
113 The identity defined by this directive, according to the properties
114 associated to the authentication method, is supposed to have read access
115 on the target server to attributes used on the proxy for ACL checking.
117 There is no risk of giving away such values; they are only used to
119 The default is to use
121 bind, with empty \fIbinddn\fP and \fIcredentials\fP,
122 which means that the related operations will be performed anonymously.
123 If not set, and if \fBidassert-bind\fP is defined, this latter identity
124 is used instead. See \fBidassert-bind\fP for details.
126 The connection between the proxy database and the remote server
127 associated to this identity is cached regardless of the lifespan
128 of the client-proxy connection that first established it.
130 .B This identity is by no means implicitly used by the proxy
131 .B when the client connects anonymously.
134 feature, instead, in some cases can be crafted to implement that behavior,
135 which is \fIintrinsically unsafe and should be used with extreme care\fP.
136 This directive obsoletes
141 The TLS settings default to the same as the main slapd TLS settings,
144 which defaults to "demand".
148 .B cancel {ABANDON|ignore|exop[-discover]}
149 Defines how to handle operation cancellation.
152 is invoked, so the operation is abandoned immediately.
155 no action is taken and any further response is ignored; this may result
156 in further response messages to be queued for that connection, so it is
157 recommended that long lasting connections are timed out either by
161 so that resources eventually get released.
166 operation (RFC 3909) is issued, resulting in the cancellation
167 of the current operation; the
169 operation waits for remote server response, so its use
170 may not be recommended.
175 extended operation is detected by reading the remote server's root DSE.
178 .B chase-referrals {YES|no}
179 enable/disable automatic referral chasing, which is delegated to the
180 underlying libldap, with rebinding eventually performed if the
181 \fBrebind-as-user\fP directive is used. The default is to chase referrals.
185 This directive causes a cached connection to be dropped an recreated
186 after a given ttl, regardless of being idle or not.
189 .B idassert-authzFrom <authz-regexp>
190 if defined, selects what
192 identities are authorized to exploit the identity assertion feature.
195 follows the rules defined for the
202 for details on the syntax of this field.
207 .B bindmethod=none|simple|sasl [binddn=<simple DN>] [credentials=<simple password>]
208 .B [saslmech=<SASL mech>] [secprops=<properties>] [realm=<realm>]
209 .B [authcId=<authentication ID>] [authzId=<authorization ID>]
210 .B [authz={native|proxyauthz}] [mode=<mode>] [flags=<flags>]
213 .B [tls_cacert=<file>]
214 .B [tls_cacertdir=<path>]
215 .B [tls_reqcert=never|allow|try|demand]
216 .B [tls_ciphersuite=<ciphers>]
217 .B [tls_crlcheck=none|peer|all]
219 Allows to define the parameters of the authentication method that is
220 internally used by the proxy to authorize connections that are
221 authenticated by other databases.
222 The identity defined by this directive, according to the properties
223 associated to the authentication method, is supposed to have auth access
224 on the target server to attributes used on the proxy for authentication
225 and authorization, and to be allowed to authorize the users.
226 This requires to have
228 privileges on a wide set of DNs, e.g.
229 .BR authzTo=dn.subtree:"" ,
230 and the remote server to have
238 for details on these statements and for remarks and drawbacks about
240 The supported bindmethods are
242 \fBnone|simple|sasl\fP
246 is the default, i.e. no \fIidentity assertion\fP is performed.
248 The authz parameter is used to instruct the SASL bind to exploit
250 SASL authorization, if available; since connections are cached,
251 this should only be used when authorizing with a fixed identity
252 (e.g. by means of the
257 Otherwise, the default
259 is used, i.e. the proxyAuthz control (Proxied Authorization, RFC 4370)
260 is added to all operations.
262 The supported modes are:
264 \fB<mode> := {legacy|anonymous|none|self}\fP
270 is given, the proxy always authorizes that identity.
271 .B <authorization ID>
278 The former is supposed to be expanded by the remote server according
279 to the authz rules; see
282 In the latter case, whether or not the
284 prefix is present, the string must pass DN validation and normalization.
288 which implies that the proxy will either perform a simple bind as the
290 or a SASL bind as the
292 and assert the client's identity when it is not anonymous.
293 Direct binds are always proxied.
294 The other modes imply that the proxy will always either perform a simple bind
297 or a SASL bind as the
300 .BR idassert-authzFrom
301 rules (see below), in which case the operation will fail;
302 eventually, it will assert some other identity according to
304 Other identity assertion modes are
308 which respectively mean that the
315 which means that no proxyAuthz control will be used, so the
319 identity will be asserted.
320 For all modes that require the use of the
322 control, on the remote server the proxy identity must have appropriate
324 permissions, or the asserted identities must have appropriate
326 permissions. Note, however, that the ID assertion feature is mostly
327 useful when the asserted identities do not exist on the remote server.
331 \fBoverride,[non-]prescriptive\fP
335 flag is used, identity assertion takes place even when the database
336 is authorizing for the identity of the client, i.e. after binding
337 with the provided identity, and thus authenticating it, the proxy
338 performs the identity assertion using the configured identity and
339 authentication method.
343 flag is used (the default), operations fail with
344 \fIinappropriateAuthentication\fP
345 for those identities whose assertion is not allowed by the
346 .B idassert-authzFrom
350 flag is used, operations are performed anonymously for those identities
351 whose assertion is not allowed by the
352 .B idassert-authzFrom
355 The TLS settings default to the same as the main slapd TLS settings,
358 which defaults to "demand".
360 The identity associated to this directive is also used for privileged
361 operations whenever \fBidassert-bind\fP is defined and \fBacl-bind\fP
362 is not. See \fBacl-bind\fP for details.
364 This directive obsoletes
365 .BR idassert-authcDN ,
366 .BR idassert-passwd ,
369 .BR idassert-method .
373 .B idle-timeout <time>
374 This directive causes a cached connection to be dropped an recreated
375 after it has been idle for the specified time.
378 .B network-timeout <time>
379 Sets the network timeout value after which
380 .BR poll (2)/ select (2)
383 returns in case of no activity.
384 The value is in seconds, and it can be specified as for
391 do not return search reference responses.
392 By default, they are returned unless request is LDAPv2.
395 .B noundeffilter <NO|yes>
398 return success instead of searching if a filter is undefined or contains
400 By default, the search is propagated after replacing undefined portions
402 .BR (!(objectClass=*)) ,
403 which corresponds to the empty result set.
406 .B protocol\-version {0,2,3}
407 This directive indicates what protocol version must be used to contact
409 If set to 0 (the default), the proxy uses the same protocol version
410 used by the client, otherwise the requested protocol is used.
411 The proxy returns \fIunwillingToPerform\fP if an operation that is
412 incompatible with the requested protocol is attempted.
415 .B proxy\-whoami {NO|yes}
416 Turns on proxying of the WhoAmI extended operation. If this option is
417 given, back-ldap will replace slapd's original WhoAmI routine with its
418 own. On slapd sessions that were authenticated by back-ldap, the WhoAmI
419 request will be forwarded to the remote LDAP server. Other sessions will
420 be handled by the local slapd, as before. This option is mainly useful
421 in conjunction with Proxy Authorization.
424 .B quarantine <interval>,<num>[;<interval>,<num>[...]]
425 Turns on quarantine of URIs that returned
426 .IR LDAP_UNAVAILABLE ,
427 so that an attempt to reconnect only occurs at given intervals instead
428 of any time a client requests an operation.
429 The pattern is: retry only after at least
431 seconds elapsed since last attempt, for exactly
433 times; then use the next pattern.
436 for the last pattern is "\fB+\fP", it retries forever; otherwise,
437 no more retries occur.
438 The process can be restarted by resetting the \fIolcDbQuarantine\fP
439 attribute of the database entry in the configuration backend.
442 .B rebind-as-user {NO|yes}
443 If this option is given, the client's bind credentials are remembered
444 for rebinds, when trying to re-establish a broken connection,
445 or when chasing a referral, if
451 .B session\-tracking\-request {NO|yes}
452 Adds session tracking control for all requests.
453 The client's IP and hostname, and the identity associated to each request,
454 if known, are sent to the remote server for informational purposes.
455 This directive is incompatible with setting \fIprotocol\-version\fP to 2.
458 .B single\-conn {NO|yes}
459 Discards current cached connection when the client rebinds.
462 .B t-f-support {NO|yes|discover}
463 enable if the remote server supports absolute filters
464 (see \fIdraft-zeilenga-ldap-t-f\fP for details).
467 support is detected by reading the remote server's root DSE.
470 .B timeout [<op>=]<val> [...]
471 This directive allows to set per-operation timeouts.
474 \fB<op> ::= bind, add, delete, modrdn, modify, compare, search\fP
476 The overall duration of the \fBsearch\fP operation is controlled either
477 by the \fBtimelimit\fP parameter or by server-side enforced
478 time limits (see \fBtimelimit\fP and \fBlimits\fP in
481 This \fBtimeout\fP parameter controls how long the target can be
482 irresponsive before the operation is aborted.
483 Timeout is meaningless for the remaining operations,
484 \fBunbind\fP and \fBabandon\fP, which do not imply any response,
485 while it is not yet implemented in currently supported \fBextended\fP
487 If no operation is specified, the timeout \fBval\fP affects all
488 supported operations.
490 Note: if the timelimit is exceeded, the operation is cancelled
491 (according to the \fBcancel\fP directive);
492 the protocol does not provide any means to rollback operations,
493 so the client will not be notified about the result of the operation,
494 which may eventually succeeded or not.
495 In case the timeout is exceeded during a bind operation, the connection
496 is destroyed, according to RFC4511.
498 Note: in some cases, this backend may issue binds prior
499 to other operations (e.g. to bind anonymously or with some prescribed
500 identity according to the \fBidassert-bind\fP directive).
501 In this case, the timeout of the operation that resulted in the bind
506 .B tls {[try-]start|[try-]propagate|ldaps}
509 .B [tls_cacert=<file>]
510 .B [tls_cacertdir=<path>]
511 .B [tls_reqcert=never|allow|try|demand]
512 .B [tls_ciphersuite=<ciphers>]
513 .B [tls_crlcheck=none|peer|all]
515 Specify the use of TLS when a regular connection is initialized. The
516 StartTLS extended operation will be used unless the URI directive protocol
517 scheme is \fBldaps://\fP. In that case this keyword may only be
518 set to "ldaps" and the StartTLS operation will not be used.
519 \fBpropagate\fP issues the StartTLS operation only if the original
521 The \fBtry-\fP prefix instructs the proxy to continue operations
522 if the StartTLS operation failed; its use is \fBnot\fP recommended.
524 The TLS settings default to the same as the main slapd TLS settings,
527 which defaults to "demand".
531 .B use-temporary-conn {NO|yes}
534 create a temporary connection whenever competing with other threads
535 for a shared one; otherwise, wait until the shared connection is available.
537 .SH BACKWARD COMPATIBILITY
538 The LDAP backend has been heavily reworked between releases 2.2 and 2.3,
539 and subsequently between 2.3 and 2.4.
540 As a side-effect, some of the traditional directives have been
541 deprecated and should be no longer used, as they might disappear
545 .B acl-authcDN "<administrative DN for access control purposes>"
546 Formerly known as the
548 it is the DN that is used to query the target server for acl checking;
549 it is supposed to have read access on the target server to attributes used
550 on the proxy for acl checking.
551 There is no risk of giving away such values; they are only used to
554 .B The acl-authcDN identity is by no means implicitly used by the proxy
555 .B when the client connects anonymously.
558 feature can be used (at own risk) for that purpose instead.
560 This directive is obsoleted by the
564 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
567 .B acl-passwd <password>
568 Formerly known as the
570 it is the password used with the above
573 This directive is obsoleted by the
577 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
580 .B idassert-authcDN "<administrative DN for proxyAuthz purposes>"
581 DN which is used to propagate the client's identity to the target
582 by means of the proxyAuthz control when the client does not
583 belong to the DIT fragment that is being proxied by back-ldap.
584 This directive is obsoleted by the
588 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
591 .B idassert-passwd <password>
592 Password used with the
595 This directive is obsoleted by the
599 when \fIbindmethod\fP=\fBsimple\fP, and will be dismissed in the future.
602 .B idassert-mode <mode> [<flags>]
604 .I identity assertion
606 This directive is obsoleted by the
610 and will be dismissed in the future.
613 .B idassert-method <method> [<saslargs>]
614 This directive is obsoleted by the
618 and will be dismissed in the future.
622 this directive is no longer supported. Use the
624 directive as described above.
627 .B server <hostname[:port]>
628 this directive is no longer supported. Use the
630 directive as described above.
633 .B suffixmassage, map, rewrite*
634 These directives are no longer supported by back-ldap; their
635 functionality is now delegated to the
637 overlay. Essentially, add a statement
641 first, and prefix all rewrite/map statements with
643 to obtain the original behavior.
647 .\" However, to ease update from existing configurations, back-ldap still
648 .\" recognizes them and automatically instantiates the
650 .\" overlay if available and not instantiated yet.
651 .\" This behavior may change in the future.
656 backend does not honor all ACL semantics as described in
657 .BR slapd.access (5).
658 In general, access checking is delegated to the remote server(s).
663 pseudo-attribute and to the other attribute values of the entries
666 operation is honored, which is performed by the frontend.
669 The LDAP backend provides basic proxying functionalities to many overlays.
672 overlay, described in
673 .BR slapo\-chain (5),
676 overlay, described in
677 .BR slapo\-translucent (5),
678 deserve a special mention.
680 Conversely, there are many overlays that are best used in conjunction
681 with the LDAP backend.
684 overlay allows caching of LDAP search requests (queries)
687 .BR slapo\-pcache (5)
691 overlay provides DN rewrite and attribute/objectClass mapping
692 capabilities to the underlying database.
700 default slapd configuration file
704 .BR slapo\-chain (5),
705 .BR slapo\-pcache (5),
707 .BR slapo\-translucent (5),
711 Howard Chu, with enhancements by Pierangelo Masarati
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