Hello everyone!

I need to set up kind of gateway for submission and imap request, in order to do that i need to find out solution for verifying user password against multiple IMAP backends. Everything for IMAP proxy works perfectly. But i have a problem with authenticating postfix against dovecot SASL.

I wonder if there is any option in dovecot to authenticate SASL requests (from postfix) against remote IMAP server or remote SASL instance. Problem is that this server has to be chosen dynamically on the user name basis, so i have to overwrite somehow host parameter in passdb imap definition.

I was thinking about using two separate password databasases, first configured as normal sql lookup with proxy flag and host field and second as imap database with host changed to some parameter matching host from previous lookup. Problem is that i don't see any variable matching host filed from passwd sql lookup.

With this approach other problem appears, because I want user to be always authenticated against remote IMAP/SASL so i have to somehow return PASSWORD_MISMATCH from my sql lookup. I tried setting up deny parameter to my sql lookup but it causes to reject whole authentication request without even asking remote imap.

Thanks a lot

Regards Miecio