Allow receiving and sending of local mail, disable remote relay on postfix

Question

I just installed mutt and postfix on my server and I've been playing around with it. Now, however, I want to make sure that no one can remotely send mail with my server as a SMTP relay.

I don't know that much about Mail servers, so for the sake of being overly clear, I want to be able to receive messages to local user accounts, send messages from local accounts to outside addresses, but not remotely send messages through the server.

Currently it receives and send's messages just how I want it, but I haven't been able to find a clear way of only disabling remote relaying.

Does anyone have any suggestions? It's a default installation of mutt and postfix, I can post any details you request. Thank you, all!

Solution

Postfix is secured that way by default. You have to explicitly misconfigure it to be an so called open relay.

For different requirements there is a documentation about several common scenarios: http://www.postfix.org/STANDARD_CONFIGURATION_README.html

Comments

[Logan]

is relay_domains in main.cf? Where are all of those variables set? It looks like exactly what I need, but I can't test it until I get home.

[Ssingh]

yeah everything is in the main.cf. To check all the config parameters just run postconf