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$OpenLDAP$
overlay dds
The database must have a rootdn specified, otherwise, the dds overlay will not be able to delete expired objects. The dds overlay may be used with any backend that implements the add , modify , search , and delete operations. Since its use may result in many internal entry lookups, adds and deletes, it should be best used in conjunction with backends that have reasonably good write performances.
The config directives that are specific to the dds overlay are prefixed by dds- , to avoid potential conflicts with directives specific to the underlying database or to other stacked overlays.
dds-max-ttl <time> Specifies the max TTL value. This is also the default TTL newly created dynamic objects receive, unless dds-default-ttl is set. When the client with a refresh extended operation requests a TTL higher than it, sizeLimitExceeded is returned. This value must be between 86400 (1 day, the default) and 31557600 (1 year plus 6 hours, as per RFC 2589).
dds-min-ttl <time> Specifies the min TTL value; clients requesting a lower TTL by means of the refresh extended operation actually obtain this value as CRP. If set to 0 (the default), no lower limit is set.
dds-default-ttl <time> Specifies the default TTL value that newly created dynamic objects get. If set to 0 (the default), the dds-max-ttl is used.
dds-interval <time> Specifies the interval between expiration checks; defaults to 1 hour.
dds-tolerance <time> Specifies an extra time that is added to the timer that actually wakes up the thread that will delete an expired dynamic object. So the nominal lifetime of the entry is that specified in the entryTtl attribute, but its lifetime will actually be "entryTtl + tolerance" . Note that there is no guarantee that the lifetime of a dynamic object will be exactly the requested TTL; due to implementation details, it may be longer, which is allowed by RFC 2589. By default, tolerance is 0.
dds-max-dynamicObjects <num> Specifies the maximum number of dynamic objects that can simultaneously exist within a naming context. This allows one to limit the amount of resources (mostly in terms of run-queue size) that are used by dynamic objects. By default, no limit is set.
dds-state {TRUE|false} Specifies if the Dynamic Directory Services feature is enabled or not. By default it is; however, a proxy does not need to keep track of dynamic objects itself, it only needs to inform the frontend that support for dynamic objects is available.
access to attrs=entryTtl by users manage by * readExample: restrict refresh to the creator of the dynamic object
access to attrs=entryTtl by dnattr=creatorsName manage by * readAnother suggested usage of dynamic objects is to implement dynamic meetings; in this case, all the participants to the meeting are allowed to refresh the meeting object, but only the creator can delete it (otherwise it will be deleted when the TTL expires) Example: assuming participant is a valid DN-valued attribute, allow users to start a meeting and to join it; restrict refresh to the participants; restrict delete to the creator
access to dn.base="cn=Meetings" attrs=children by users write access to dn.onelevel="cn=Meetings" attrs=entry by dnattr=creatorsName write by * read access to dn.onelevel="cn=Meetings" attrs=participant by dnattr=creatorsName write by users selfwrite by * read access to dn.onelevel="cn=Meetings" attrs=entryTtl by dnattr=participant manage by * read
syncrepl ... exattrs=entryTtl,entryExpireTimestampIn any case the overlay must be either statically built in or run-time loaded by the consumer, so that it is aware of the entryExpireTimestamp operational attribute; however, it must not be configured in the shadow database. Currently, there is no means to remove the dynamicObject class from the entry; this may be seen as a feature, since it allows one to see the dynamic properties of the object.
ETCDIR/slapd.conf default slapd configuration file
Indexes created Fri Jul 10 00:26:32 UTC 2026