We are looking for forum engine which may actually maintain user data into LDAP, maybe via mods. Core point is about ability to maintain the data, i.e. all user profile settings, like nickname, password, email, avatar, birthday and others (preferably configurable).
One example of good ldap integration, level of which I'm expecting, is drupal's ldap integration, which allows to map any user's attribute into ldap and keeps it in sync with database.
Year ago I've done a small research over existing Free&FOSS engines and find out few forum engines with LDAP integration, namely SFM, phpBB and something else.
The most maintained solution were provided by phpBB3, which supports LDAP integration out-of-box, but it is unable to sync data with changes in LDAP server made by other software. Actually it wasn't even propagating changes back, I'm not saying about ability to map additional attributes (other than name/password/email). Also, I haven't found any forum with architecture which have proper abstraction over user settings, thus I doubt that this engines (including phpBB) are possible to mod such functionality without introducing dramatic changes into core codebase.
More recent research showed that even some commercial software, like IPB is unable to keep it's database synced with LDAP directory and map additional attributes.
In other words, all support I've seen so far is simple user creation upon first user's login, which is not good for us, as forum is not primary site and should not maintain it's own users base (to reduce risk of possible collisions).
LDAP import is required due to many other services (ftp, email, jabber, drupal site) using same users base. Currently we have forum embedded into Drupal site, but we are unsatisfied with it's features.
BTW, we are using Linux and this is not duplicate of this question, as it's author seems to be satisfied with behaviour described above.
So, my question is: Are there any (preferably FOSS&free) forum engines that may import, export, keep in sync, or otherwise integrade with LDAP user database (preferably with ability to map additional fields to ldap attributes)?