slapd-ldap - LDAP backend to slapd

/etc/ldap/slapd.conf

The LDAP backend to 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.

These 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 slapd.conf(5) manual page.

Note: It is strongly recommended to set

lastmod  off

for every ldap and 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.

uri <ldapurl>

LDAP server to use. Multiple URIs can be set in in a single ldapurl argument, resulting in the underlying library automatically call the first server of the list that responds, e.g.

uri "ldap://host/ ldap://backup-host"

The URI list is space- or comma-separated.

server <hostport>

Obsolete option; same as `uri ldap://<hostport>/'.

binddn <administrative DN for access control purposes>

DN which is used to query the target server for acl checking; it should 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.

bindpw <password>

Password used with the bind DN above.

proxyauthzdn <administrative DN for proxyAuthz purposes>

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 proxyauthzdn identity on the remote server to have proxyAuthz privileges on a wide set of DNs, e.g. saslAuthzTo=dn.regex:.*, and the remote server to have sasl-authz-policy set to to or both. See slapd.conf(5) for details on these statements and for remarks and drawbacks about their usage.

proxyauthzpw <password>

Password used with the proxy authz DN above.

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.

rebind-as-user

If this option is given, the client's bind credentials are remembered for rebinds when chasing referrals.

suffixmassage <suffix> <massaged (remote) suffix>

DNs ending with <suffix> in a request are changed to end with <remote suffix> before sending the request to the remote server, and <remote suffix> in the results are changed back to <suffix> before returning them to the client. The <suffix> field must be defined as a valid suffix for the current database.

map {attribute | objectclass} [<local name> | *] {<foreign name> | *}

Map attribute names and object classes from the foreign server to different values on the local slapd. The reason is that some attributes might not be part of the local slapd's schema, some attribute names might be different but serve the same purpose, etc. If local or foreign name is `*', the name is preserved. If local name is omitted, the foreign name is removed. Unmapped names are preseved if both local and foreign name are `*', and removed if local name is omitted and foreign name is `*'.

rewrite*

The rewrite options are described in the "REWRITING" section of the slapd-meta(5) manual page.

This maps the OpenLDAP objectclass `groupOfNames' to the Active Directory objectclass `group':

map objectclass groupOfNames group

This presents a limited attribute set from the foreign server:

map attribute cn *
map attribute sn *
map attribute manager *
map attribute description *
map attribute *

These lines map cn, sn, manager, and description to themselves, and any other attribute gets "removed" from the object before it is sent to the client (or sent up to the LDAP server). This is obviously a simplistic example, but you get the point.

/etc/ldap/slapd.conf

default slapd configuration file

slapd.conf(5), slapd-meta(5), slapd(8), ldap(3).

Howard Chu, with enhancements by Pierangelo Masarati