1SLAPD-LDAP(5) File Formats Manual SLAPD-LDAP(5)
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6 slapd-ldap - LDAP backend to slapd
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9 /etc/openldap/slapd.conf
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12 The LDAP backend to slapd(8) is not an actual database; instead it acts
13 as a proxy to forward incoming requests to another LDAP server. While
14 processing requests it will also chase referrals, so that referrals are
15 fully processed instead of being returned to the slapd client.
16 Sessions that explicitly Bind to the back-ldap database always create
18 their own private connection to the remote LDAP server. Anonymous ses‐
19 sions will share a single anonymous connection to the remote server.
20 For sessions bound through other mechanisms, all sessions with the same
21 DN will share the same connection. This connection pooling strategy can
22 enhance the proxy's efficiency by reducing the overhead of repeatedly
23 making/breaking multiple connections.
24 The ldap database can also act as an information service, i.e. the
26 identity of locally authenticated clients is asserted to the remote
27 server, possibly in some modified form. For this purpose, the proxy
28 binds to the remote server with some administrative identity, and, if
29 required, authorizes the asserted identity. See the idassert-* rules
30 below. The administrative identity of the proxy, on the remote server,
31 must be allowed to authorize by means of appropriate authzTo rules; see
32 slapd.conf(5) for details.
33 The proxy instance of slapd(8) must contain schema information for the
35 attributes and objectClasses used in filters, request DNs and request-
36 related data in general. It should also contain schema information for
37 the data returned by the proxied server. It is the responsibility of
38 the proxy administrator to keep the schema of the proxy lined up with
39 that of the proxied server.
40 Note: When looping back to the same instance of slapd(8), each connec‐
43 tion requires a new thread; as a consequence, slapd(8) must be compiled
44 with thread support, and the threads parameter may need some tuning; in
45 those cases, one may consider using slapd-relay(5) instead, which per‐
46 forms the relayed operation internally and thus reuses the same connec‐
47 tion.
48
51 These slapd.conf options apply to the LDAP backend database. That is,
52 they must follow a "database ldap" line and come before any subsequent
53 "backend" or "database" lines. Other database options are described in
54 the slapd.conf(5) manual page.
55 Note: In early versions of back-ldap it was recommended to always set
58 lastmod off
60 for ldap and meta databases. This was required because operational
62 attributes related to entry creation and modification should not be
63 proxied, as they could be mistakenly written to the target server(s),
64 generating an error. The current implementation automatically sets
65 lastmod to off, so its use is redundant and should be omitted.
66 uri <ldapurl>
69 LDAP server to use. Multiple URIs can be set in a single lda‐
70 purl argument, resulting in the underlying library automatically
71 calling the first server of the list that responds, e.g.
72 uri "ldap://host/ ldap://backup-host/"
74 The URI list is space- or comma-separated. Whenever the server
76 that responds is not the first one in the list, the list is
77 rearranged and the responsive server is moved to the head, so
78 that it will be first contacted the next time a connection needs
79 to be created.
80 acl-bind bindmethod=simple|sasl [binddn=<simple DN>]
82 [credentials=<simple password>] [saslmech=<SASL mech>]
83 [secprops=<properties>] [realm=<realm>] [authcId=<authentication
84 ID>] [authzId=<authorization ID>] [starttls=no|yes|critical]
85 [tls_cert=<file>] [tls_key=<file>] [tls_cacert=<file>]
86 [tls_cacertdir=<path>] [tls_reqcert=never|allow|try|demand]
87 [tls_ciphersuite=<ciphers>] [tls_protocol_min=<major>[.<minor>]]
88 [tls_crlcheck=none|peer|all]
89 Allows to define the parameters of the authentication method
90 that is internally used by the proxy to collect info related to
91 access control, and whenever an operation occurs with the
92 identity of the rootdn of the LDAP proxy database. The identity
93 defined by this directive, according to the properties
94 associated to the authentication method, is supposed to have
95 read access on the target server to attributes used on the proxy
96 for ACL checking.
97 There is no risk of giving away such values; they are only used
99 to check permissions. The default is to use simple bind, with
100 empty binddn and credentials, which means that the related
101 operations will be performed anonymously. If not set, and if
102 idassert-bind is defined, this latter identity is used instead.
103 See idassert-bind for details.
104 The connection between the proxy database and the remote server
106 associated to this identity is cached regardless of the lifespan
107 of the client-proxy connection that first established it.
108 This identity is not implicitly used by the proxy when the
110 client connects anonymously. The idassert-bind feature,
111 instead, in some cases can be crafted to implement that
112 behavior, which is intrinsically unsafe and should be used with
113 extreme care. This directive obsoletes acl-authcDN, and
114 acl-passwd.
115 The TLS settings default to the same as the main slapd TLS
117 settings, except for tls_reqcert which defaults to "demand".
118 cancel {ABANDON|ignore|exop[-discover]}
121 Defines how to handle operation cancellation. By default,
122 abandon is invoked, so the operation is abandoned immediately.
123 If set to ignore, no action is taken and any further response is
124 ignored; this may result in further response messages to be
125 queued for that connection, so it is recommended that long
126 lasting connections are timed out either by idle-timeout or
127 conn-ttl, so that resources eventually get released. If set to
128 exop, a cancel operation (RFC 3909) is issued, resulting in the
129 cancellation of the current operation; the cancel operation
130 waits for remote server response, so its use may not be
131 recommended. If set to exop-discover, support of the cancel
132 extended operation is detected by reading the remote server's
133 root DSE.
134 chase-referrals {YES|no}
137 enable/disable automatic referral chasing, which is delegated to
138 the underlying libldap, with rebinding eventually performed if
139 the rebind-as-user directive is used. The default is to chase
140 referrals.
141 conn-ttl <time>
144 This directive causes a cached connection to be dropped and
145 recreated after a given ttl, regardless of being idle or not.
146 idassert-authzFrom <authz-regexp>
149 if defined, selects what local identities are authorized to
150 exploit the identity assertion feature. The string <authz-
151 regexp> follows the rules defined for the authzFrom attribute.
152 See slapd.conf(5), section related to authz-policy, for details
153 on the syntax of this field.
154 idassert-bind bindmethod=none|simple|sasl [binddn=<simple DN>]
157 [credentials=<simple password>] [saslmech=<SASL mech>]
158 [secprops=<properties>] [realm=<realm>] [authcId=<authentication
159 ID>] [authzId=<authorization ID>] [authz={native|proxyauthz}]
160 [mode=<mode>] [flags=<flags>] [starttls=no|yes|critical]
161 [tls_cert=<file>] [tls_key=<file>] [tls_cacert=<file>]
162 [tls_cacertdir=<path>] [tls_reqcert=never|allow|try|demand]
163 [tls_ciphersuite=<ciphers>] [tls_protocol_min=<version>]
164 [tls_crlcheck=none|peer|all]
165 Allows to define the parameters of the authentication method
166 that is internally used by the proxy to authorize connections
167 that are authenticated by other databases. Direct binds are
168 always proxied without any idassert handling.
169 The identity defined by this directive, according to the
171 properties associated to the authentication method, is supposed
172 to have auth access on the target server to attributes used on
173 the proxy for authentication and authorization, and to be
174 allowed to authorize the users. This requires to have
175 proxyAuthz privileges on a wide set of DNs, e.g.
176 authzTo=dn.subtree:"", and the remote server to have
177 authz-policy set to to or both. See slapd.conf(5) for details
178 on these statements and for remarks and drawbacks about their
179 usage. The supported bindmethods are
180 none|simple|sasl
182 where none is the default, i.e. no identity assertion is
184 performed.
185 The authz parameter is used to instruct the SASL bind to exploit
187 native SASL authorization, if available; since connections are
188 cached, this should only be used when authorizing with a fixed
189 identity (e.g. by means of the authzDN or authzID parameters).
190 Otherwise, the default proxyauthz is used, i.e. the proxyAuthz
191 control (Proxied Authorization, RFC 4370) is added to all
192 operations.
193 The supported modes are:
195 <mode> := {legacy|anonymous|none|self}
197 If <mode> is not present, and authzId is given, the proxy always
199 authorizes that identity. <authorization ID> can be
200 u:<user>
202 [dn:]<DN>
204 The former is supposed to be expanded by the remote server
206 according to the authz rules; see slapd.conf(5) for details. In
207 the latter case, whether or not the dn: prefix is present, the
208 string must pass DN validation and normalization.
209 The default mode is legacy, which implies that the proxy will
211 either perform a simple bind as the authcDN or a SASL bind as
212 the authcID and assert the client's identity when it is not
213 anonymous. The other modes imply that the proxy will always
214 either perform a simple bind as the authcDN or a SASL bind as
215 the authcID, unless restricted by idassert-authzFrom rules (see
216 below), in which case the operation will fail; eventually, it
217 will assert some other identity according to <mode>. Other
218 identity assertion modes are anonymous and self, which
219 respectively mean that the empty or the client's identity will
220 be asserted; none, which means that no proxyAuthz control will
221 be used, so the authcDN or the authcID identity will be
222 asserted. For all modes that require the use of the proxyAuthz
223 control, on the remote server the proxy identity must have
224 appropriate authzTo permissions, or the asserted identities must
225 have appropriate authzFrom permissions. Note, however, that the
226 ID assertion feature is mostly useful when the asserted
227 identities do not exist on the remote server.
228 Flags can be
230 override,[non-]prescriptive,proxy-authz-[non-]critical
232 When the override flag is used, identity assertion takes place
234 even when the database is authorizing for the identity of the
235 client, i.e. after binding with the provided identity, and thus
236 authenticating it, the proxy performs the identity assertion
237 using the configured identity and authentication method.
238 When the prescriptive flag is used (the default), operations
240 fail with inappropriateAuthentication for those identities whose
241 assertion is not allowed by the idassert-authzFrom patterns. If
242 the non-prescriptive flag is used, operations are performed
243 anonymously for those identities whose assertion is not allowed
244 by the idassert-authzFrom patterns.
245 When the proxy-authz-non-critical flag is used (the default),
247 the proxyAuthz control is not marked as critical, in violation
248 of RFC 4370. Use of proxy-authz-critical is recommended.
249 The TLS settings default to the same as the main slapd TLS
251 settings, except for tls_reqcert which defaults to "demand".
252 The identity associated to this directive is also used for
254 privileged operations whenever idassert-bind is defined and
255 acl-bind is not. See acl-bind for details.
256 This directive obsoletes idassert-authcDN, idassert-passwd,
258 idassert-mode, and idassert-method.
259 idassert-passthru <authz-regexp>
262 if defined, selects what local identities bypass the identity
263 assertion feature. Those identities need to be known by the
264 remote host. The string <authz-regexp> follows the rules
265 defined for the authzFrom attribute. See slapd.conf(5), section
266 related to authz-policy, for details on the syntax of this
267 field.
268 idle-timeout <time>
272 This directive causes a cached connection to be dropped an
273 recreated after it has been idle for the specified time.
274 keepalive <idle>:<probes>:<interval>
277 The keepalive parameter sets the values of idle, probes, and
278 interval used to check whether a socket is alive; idle is the
279 number of seconds a connection needs to remain idle before TCP
280 starts sending keepalive probes; probes is the maximum number of
281 keepalive probes TCP should send before dropping the connection;
282 interval is interval in seconds between individual keepalive
283 probes. Only some systems support the customization of these
284 values; the keepalive parameter is ignored otherwise, and
285 system-wide settings are used.
286 network-timeout <time>
289 Sets the network timeout value after which poll(2)/select(2)
290 following a connect(2) returns in case of no activity. The
291 value is in seconds, and it can be specified as for
292 idle-timeout.
293 norefs <NO|yes>
296 If yes, do not return search reference responses. By default,
297 they are returned unless request is LDAPv2.
298 noundeffilter <NO|yes>
301 If yes, return success instead of searching if a filter is
302 undefined or contains undefined portions. By default, the
303 search is propagated after replacing undefined portions with
304 (!(objectClass=*)), which corresponds to the empty result set.
305 onerr {CONTINUE|stop}
308 This directive allows to select the behavior in case an error is
309 returned by the remote server during a search. The default,
310 continue, consists in returning success. If the value is set to
311 stop, the error is returned to the client.
312 protocol-version {0,2,3}
315 This directive indicates what protocol version must be used to
316 contact the remote server. If set to 0 (the default), the proxy
317 uses the same protocol version used by the client, otherwise the
318 requested protocol is used. The proxy returns
319 unwillingToPerform if an operation that is incompatible with the
320 requested protocol is attempted.
321 proxy-whoami {NO|yes}
324 Turns on proxying of the WhoAmI extended operation. If this
325 option is given, back-ldap will replace slapd's original WhoAmI
326 routine with its own. On slapd sessions that were authenticated
327 by back-ldap, the WhoAmI request will be forwarded to the remote
328 LDAP server. Other sessions will be handled by the local slapd,
329 as before. This option is mainly useful in conjunction with
330 Proxy Authorization.
331 quarantine <interval>,<num>[;<interval>,<num>[...]]
334 Turns on quarantine of URIs that returned LDAP_UNAVAILABLE, so
335 that an attempt to reconnect only occurs at given intervals
336 instead of any time a client requests an operation. The pattern
337 is: retry only after at least interval seconds elapsed since
338 last attempt, for exactly num times; then use the next pattern.
339 If num for the last pattern is "+", it retries forever;
340 otherwise, no more retries occur. The process can be restarted
341 by resetting the olcDbQuarantine attribute of the database entry
342 in the configuration backend.
343 rebind-as-user {NO|yes}
346 If this option is given, the client's bind credentials are
347 remembered for rebinds, when trying to re-establish a broken
348 connection, or when chasing a referral, if chase-referrals is
349 set to yes.
350 session-tracking-request {NO|yes}
353 Adds session tracking control for all requests. The client's IP
354 and hostname, and the identity associated to each request, if
355 known, are sent to the remote server for informational purposes.
356 This directive is incompatible with setting protocol-version to
357 2.
358 single-conn {NO|yes}
361 Discards current cached connection when the client rebinds.
362 t-f-support {NO|yes|discover}
365 enable if the remote server supports absolute filters (see RFC
366 4526 for details). If set to discover, support is detected by
367 reading the remote server's root DSE.
368 timeout [<op>=]<val> [...]
371 This directive allows to set per-operation timeouts. Operations
372 can be
373 <op> ::= bind, add, delete, modrdn, modify, compare, search
375 The overall duration of the search operation is controlled
377 either by the timelimit parameter or by server-side enforced
378 time limits (see timelimit and limits in slapd.conf(5) for
379 details). This timeout parameter controls how long the target
380 can be irresponsive before the operation is aborted. Timeout is
381 meaningless for the remaining operations, unbind and abandon,
382 which do not imply any response, while it is not yet implemented
383 in currently supported extended operations. If no operation is
384 specified, the timeout val affects all supported operations.
385 Note: if the timelimit is exceeded, the operation is cancelled
387 (according to the cancel directive); the protocol does not
388 provide any means to rollback operations, so the client will not
389 be notified about the result of the operation, which may
390 eventually succeeded or not. In case the timeout is exceeded
391 during a bind operation, the connection is destroyed, according
392 to RFC4511.
393 Note: in some cases, this backend may issue binds prior to other
395 operations (e.g. to bind anonymously or with some prescribed
396 identity according to the idassert-bind directive). In this
397 case, the timeout of the operation that resulted in the bind is
398 used.
399 tls {[try-]start|[try-]propagate|ldaps} [tls_cert=<file>]
402 [tls_key=<file>] [tls_cacert=<file>] [tls_cacertdir=<path>]
403 [tls_reqcert=never|allow|try|demand] [tls_ciphersuite=<ciphers>]
404 [tls_crlcheck=none|peer|all]
405 Specify the use of TLS when a regular connection is initialized.
406 The StartTLS extended operation will be used unless the URI
407 directive protocol scheme is ldaps://. In that case this keyword
408 may only be set to "ldaps" and the StartTLS operation will not
409 be used. propagate issues the StartTLS operation only if the
410 original connection did. The try- prefix instructs the proxy to
411 continue operations if the StartTLS operation failed; its use is
412 not recommended.
413 The TLS settings default to the same as the main slapd TLS
415 settings, except for tls_reqcert which defaults to "demand".
416 use-temporary-conn {NO|yes}
419 when set to yes, create a temporary connection whenever
420 competing with other threads for a shared one; otherwise, wait
421 until the shared connection is available.
422
425 The LDAP backend has been heavily reworked between releases 2.2 and
426 2.3, and subsequently between 2.3 and 2.4. As a side-effect, some of
427 the traditional directives have been deprecated and should be no longer
428 used, as they might disappear in future releases.
429 acl-authcDN <administrative DN for access control purposes>
432 Formerly known as the binddn, it is the DN that is used to query
433 the target server for acl checking; it is supposed to have read
434 access on the target server to attributes used on the proxy for
435 acl checking. There is no risk of giving away such values; they
436 are only used to check permissions.
437 The acl-authcDN identity is by no means implicitly used by the
439 proxy when the client connects anonymously. The idassert-*
440 feature can be used (at own risk) for that purpose instead.
441 This directive is obsoleted by the binddn arg of acl-bind when
443 bindmethod=simple, and will be dismissed in the future.
444 acl-passwd <password>
447 Formerly known as the bindpw, it is the password used with the
448 above acl-authcDN directive. This directive is obsoleted by the
449 credentials arg of acl-bind when bindmethod=simple, and will be
450 dismissed in the future.
451 idassert-authcDN <administrative DN for proxyAuthz purposes>
454 DN which is used to propagate the client's identity to the
455 target by means of the proxyAuthz control when the client does
456 not belong to the DIT fragment that is being proxied by back-
457 ldap. This directive is obsoleted by the binddn arg of
458 idassert-bind when bindmethod=simple, and will be dismissed in
459 the future.
460 idassert-passwd <password>
463 Password used with the idassert-authcDN above. This directive
464 is obsoleted by the crendentials arg of idassert-bind when
465 bindmethod=simple, and will be dismissed in the future.
466 idassert-mode <mode> [<flags>]
469 defines what type of identity assertion is used. This directive
470 is obsoleted by the mode arg of idassert-bind, and will be
471 dismissed in the future.
472 idassert-method <method> [<saslargs>]
475 This directive is obsoleted by the bindmethod arg of
476 idassert-bind, and will be dismissed in the future.
477 port <port>
480 this directive is no longer supported. Use the uri directive as
481 described above.
482 server <hostname[:port]>
485 this directive is no longer supported. Use the uri directive as
486 described above.
487 suffixmassage, map, rewrite*
490 These directives are no longer supported by back-ldap; their
491 functionality is now delegated to the rwm overlay. Essentially,
492 add a statement
493 overlay rwm
495 first, and prefix all rewrite/map statements with rwm- to obtain
497 the original behavior. See slapo-rwm(5) for details.
498
501 The ldap backend does not honor all ACL semantics as described in
502 slapd.access(5). In general, access checking is delegated to the
503 remote server(s). Only read (=r) access to the entry pseudo-attribute
504 and to the other attribute values of the entries returned by the search
505 operation is honored, which is performed by the frontend.
506
509 The LDAP backend provides basic proxying functionalities to many
510 overlays. The chain overlay, described in slapo-chain(5), and the
511 translucent overlay, described in slapo-translucent(5), deserve a
512 special mention.
513 Conversely, there are many overlays that are best used in conjunction
515 with the LDAP backend. The proxycache overlay allows caching of LDAP
516 search requests (queries) in a local database. See slapo-pcache(5) for
517 details. The rwm overlay provides DN rewrite and attribute/objectClass
518 mapping capabilities to the underlying database. See slapo-rwm(5) for
519 details.
520
523 /etc/openldap/slapd.conf
524 default slapd configuration file
525
527 slapd.conf(5), slapd-config(5), slapd-meta(5), slapo-chain(5),
528 slapo-pcache(5), slapo-rwm(5), slapo-translucent(5), slapd(8), ldap(3).
529
531 Howard Chu, with enhancements by Pierangelo Masarati
532OpenLDAP 2.4.40 2014/09/20 SLAPD-LDAP(5)