Smtp auth for outgoing mail

The client will be running a SMTP server locally, which will encrypt each email and relay it to the provider's SMTP.

Is there anything defined regarding SMTP auth in the provider? The ideal case would be to have token auth, like we do with everything else, but that would involve developing a new daemon to handle this on the server.

I'm not really sure what direction to go, hence this ticket.

(from redmine: created on 2013-05-07, closed on 2013-08-08, blocks #2649, precedes #2400 (closed))