Yes, but that's not all. Basically there is an Authenticate module that you can replace. We have written a UBB.pm module that will use the UBB membership system, basically giving everyone on your UBB board an account. This works off a flat file system.
An LDAP add on would be just as easy, or any sql table. The authentication is completely separate from the program. We have also made it fairly easy to transfer sessions back and forth so if you are logged into one system, moving to Gossamer Mail will not have to involve re logging in.
Cheers,
Alex
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