I'm using postfix server with webmin, which means my web server is on the same machine.
My mail setup is as follows: I have an external e-mail solution (paid for per mailbox) which I use and thus the MX records etc are setup correctly to go there.
However I also have setup a local mailbox for the domain in question so that I can send e-mails from the local webserver securely and automatically via a web app. This is reflected in the SPF records.
The problem now is when I send e-mails using the local server to my own domain. Postfix tries to look locally first because I have setup a local mailbox. But I don't want that to happen as the real mailboxes are in the external server.
Where do I have to look and what do I have to do in order to setup postfix using webmin so that it will either:
don't look locally for certain domains even if there is a mailbox locally
don't look locally whatever the domain even if there is a mailbox locally.