pass-through authentication

We are attempting to set up an LDAP server which will answer queries from an application. The database will contain metadata on a set of users in the application. The application will also query the server to authenticate the user’s password, however, this server will not house the password. That resides on another server, which our server will query. We do not have administrative rights to the other server.

The difficulty we are having now is setting up the pass-through authentication for the passwords. Any pointers in how to proceed with this would be greatly appreciated.

Regards,

Tim