Hi, I have a question. We have an outside service provider that filters our mail and checks for viruses and spam. What I would like to do is to block the smtp traffic so that I only receive emails from my providers relay hosts IPs.

Is this in any way possible through Zimbra console?
I've been having a look and don't see how. The only way I came up with was to create an IP table rule that would block all traffic on port 25 and allow only the IPs from my provider.

Does that make any sence at all? Is there an easier way to do this with postfix?