.TH SLAPD-LDAP 5 "RELEASEDATE" "OpenLDAP LDVERSION" .\" Copyright 1998-2005 The OpenLDAP Foundation All Rights Reserved. .\" Copying restrictions apply. See COPYRIGHT/LICENSE. .\" $OpenLDAP$ .SH NAME slapd-ldap \- LDAP backend to slapd .SH SYNOPSIS ETCDIR/slapd.conf .SH DESCRIPTION The LDAP backend to .BR slapd (8) is not an actual database; instead it acts as a proxy to forward incoming requests to another LDAP server. While processing requests it will also chase referrals, so that referrals are fully processed instead of being returned to the slapd client. Sessions that explicitly Bind to the back-ldap database always create their own private connection to the remote LDAP server. Anonymous sessions will share a single anonymous connection to the remote server. For sessions bound through other mechanisms, all sessions with the same DN will share the same connection. This connection pooling strategy can enhance the proxy's efficiency by reducing the overhead of repeatedly making/breaking multiple connections. The ldap database can also act as an information service, i.e. the identity of locally authenticated clients is asserted to the remote server, possibly in some modified form. For this purpose, the proxy binds to the remote server with some administrative identity, and, if required, authorizes the asserted identity. See the .IR idassert- * rules below. The administrative identity of the proxy, on the remote server, must be allowed to authorize by means of appropriate .B authzTo rules; see .BR slapd.conf (5) for details. .SH CONFIGURATION These .B slapd.conf options apply to the LDAP backend database. That is, they must follow a "database ldap" line and come before any subsequent "backend" or "database" lines. Other database options are described in the .BR slapd.conf (5) manual page. .LP Note: In early versions of back-ldap it was recommended to always set .LP .RS .nf lastmod off .fi .RE .LP for every .B ldap and .B meta database. This is because operational attributes related to entry creation and modification should not be used, as they could be passed to the target servers, generating an error. The current implementation automatically sets ldapmod to off, so its use is redundant and can be safely omitted. .TP .B uri LDAP server to use. Multiple URIs can be set in in a single .B ldapurl argument, resulting in the underlying library automatically call the first server of the list that responds, e.g. \fBuri "ldap://host/ ldap://backup-host"\fP The URI list is space- or comma-separated. .\".TP .\".B server .\"Obsolete option; same as `uri ldap:///'. .TP .B acl-authcDN "" DN which is used to query the target server for acl checking; it is supposed to have read access on the target server to attributes used on the proxy for acl checking. There is no risk of giving away such values; they are only used to check permissions. .B The acl-authcDN identity is by no means implicitly used by the proxy .B when the client connects anonymously. See the .B idassert-* feature instead. .TP .B acl-passwd Password used with the .B acl-authcDN above. .TP .B idassert-authcdn "" DN which is used to propagate the client's identity to the target by means of the proxyAuthz control when the client does not belong to the DIT fragment that is being proxyied by back-ldap. This is useful when operations performed by users bound to another backend are propagated through back-ldap. This requires the entry with .B idassert-authcdn identity on the remote server to have .B proxyAuthz privileges on a wide set of DNs, e.g. .BR authzTo=dn.subtree:"" , and the remote server to have .B authz-policy set to .B to or .BR both . See .BR slapd.conf (5) for details on these statements and for remarks and drawbacks about their usage. .TP .B idassert-passwd Password used with the .B idassert-authcdn above. .TP .B idassert-mode [] defines what type of .I identity assertion is used. The supported modes are: \fB := {legacy|anonymous|none||self}\fP \fB := {override}\fP \fB := {u:|[dn:]}\fP The default is .BR legacy , which implies that the proxy will bind as .I idassert-authcdn and assert the client's identity when it is not anonymous. Direct binds are always proxied. The other modes imply that the proxy will always bind as .IR idassert-authcdn , unless restricted by .BR idassert-authzFrom rules (see below), in which case the operation will fail; eventually, it will assert some other identity according to .BR . Other identity assertion modes are .BR anonymous and .BR self , which respectively mean that the .I empty or the .IR client 's identity will be asserted; .BR none , which means that no proxyAuthz control will be used, so the .I idassert-authcdn identity will be asserted. Moreover, if a string prefixed with .B u: or .B dn: is used as .BR , that identity will be asserted. Ths string is also treated as a DN if it is not prefixed by any recognized type indicator. Whether or not the .B dn: prefix is present, the string must pass DN validation and normalization. For all modes that require the use of the .I proxyAuthz control, on the remote server the proxy identity must have appropriate .I authzTo permissions, or the asserted identities must have appropriate .I authzFrom permissions. Note, however, that the ID assertion feature is mostly useful when the asserted identities do not exist on the remote server. When the .B override flag is used, identity assertion takes place even when the database is authorizing for the identity of the client, i.e. after binding with the provided identity, and thus authenticating it, the proxy performs the identity assertion using the configured identity and authentication method. .RE .TP .B idassert-authzFrom if defined, selects what .I local identities are authorized to exploit the identity assertion feature. The string .B follows the rules defined for the .I authzFrom attribute. See .BR slapd.conf (5), section related to .BR authz-policy , for details on the syntax of this field. .TP .B idassert-method [] where valid method values are \fB := {none|simple|sasl}\fP \fB := [mech=] [realm=] [authcid=] [cred=] [authz={native|proxyauthz}]\fP If method is .IR sasl , extra parameters can be given as described above. The default is .BR simple ; .B none inhibits proxy authorization; .B sasl uses a SASL bind with the above parameters; if required, .I authorization is performed by means of native SASL mechanism, and no proxyAuthz is used for subsequent operations. .RE .TP .B proxy-whoami Turns on proxying of the WhoAmI extended operation. If this option is given, back-ldap will replace slapd's original WhoAmI routine with its own. On slapd sessions that were authenticated by back-ldap, the WhoAmI request will be forwarded to the remote LDAP server. Other sessions will be handled by the local slapd, as before. This option is mainly useful in conjunction with Proxy Authorization. .TP .B rebind-as-user If this option is given, the client's bind credentials are remembered for rebinds when chasing referrals. Useful in conjunction with \fBchase-referrals\fP, useless if \fBdont-chase-referrals\fP is set. .LP .B chase-referrals .br .B dont-chase-referrals .RS enable/disable automatic referral chasing, which is delegated to the underlying libldap, with rebinding eventually performed if the \fBrebind-as-user\fP directive is used. The default is to chase referrals. .RE .LP .B tls-start .br .B tls-try-start .br .B tls-propagate .br .B tls-try-propagate .RS execute the start TLS extended operation when the connection is initialized; only works if the URI directive protocol scheme is not \fBldaps://\fP. The \fBtls-propagate\fP version issues the Start TLS exop only if the original connection did. \fBtry-start-tls\fP and \fBtry-propagate-tls\fP continue operations if start TLS failed. .RE .TP .B suffixmassage, map, rewrite* These directives are no longer supported by back-ldap; their functionality is now delegated to the .B rwm overlay; see .BR slapo-rwm (5) for details. However, to ease update from existing configurations, back-ldap still recognizes them and automatically instantiates the .B rwm overlay if available and not instantiated yet. This behavior may change in the future. .SH ACCESS CONTROL The .B ldap backend does not honor all ACL semantics as described in .BR slapd.access (5). In general, access checking is delegated to the remote server(s). Only .B read (=r) access to the .B entry pseudo-attribute and to the other attribute values of the entries returned by the .B search operation is honored, which is performed by the frontend. .SH PROXY CACHE OVERLAY The proxy cache overlay allows caching of LDAP search requests (queries) in a local database. See .BR slapo-pcache (5) for details. .SH FILES .TP ETCDIR/slapd.conf default slapd configuration file .SH SEE ALSO .BR slapd.conf (5), .BR slapd\-meta (5), .BR slapo\-pcache (5), .BR slapo\-rwm (5), .BR slapd (8), .BR ldap (3). .SH AUTHOR Howard Chu, with enhancements by Pierangelo Masarati