I have an Ubuntu server running Virtualmin (with Postfix).
It is steadfastly refusing to allow me to relay when I authenticate. However I can't make any sense of what is going on.
Postfix's main.cf says: smtpd_sasl_auth_enable = yes smtpd_recipient_restrictions = permit_sasl_authenticated permit_mynetworks reject_unauth_destination .. which I understand to mean that provided I authenticate I can send anywhere.
The error I'm getting is: connect from [...] NOQUEUE: reject: RCPT from [...]: 550 5.1.1 user@example.com: Recipient address rejected: User unknown in virtual alias table; from=user@mysite to=user@example.com proto=ESMTP helo=<[...]> disconnect from [...]
.. where [...] is my IP/hostname, user@example.com is the address I'm trying to relay to, user@mysite is the user I'm trying to authenticate as.
If I disable authentication in my mail client, I get "relaying denied" which I would expect. If I change my password I get a password error, so I am definitely authenticating correctly. If I try sending an email (no authentication, plain SMTP) to invaliduser@mysite I get the same error as above, which is when I would expect to get it (trying to send to a user on my server that doesn't exist). However I'm trying to relay to a different server altogether so I can make sense of the error message in that context at all?
Mark