Before I came to Virtualmin, I managed my own Postfix main.cf. I’ve discovered that Webmin’s default is to be an open relay. Yikes! So, I’d like to clamp this down.
First, here’s what I’ve done in the past:
You might notice that I’m using the SQLgrey code above (check_policy_service) that has been extraordinarily useful in combatting spam.
Can anyone share what you’ve done to (1) make sure that Virtualmin doesn’t allow for open relays (since we’re in a server farm with network neighbors that can’t be trusted); and, (2) make sure that Virtualmin is set to aggressively block SPAM?