I have set-up Postfix with Spamassassin on Ubuntu 12.04.5. Fundamental usage of Postfix is to (pipe) trigger a PHP file. Till here I've arrived successfully.
Now, to avoid unneccessary load on the server, and also to avoid unwanted mails triggering my PHP script, I want to configure Postfix to allow mails only from
[email protected] and reject everything else.
How to achieve this absolute lock-down on mail server unless mail comes from
[email protected]?