Disallow users from sending/recieving external email

[gking]

Hello, I work in a School in the UK and we have recently implemented a Zimbra server for testing purposes. One of the requirements is that we have the ability to disallow accounts from sending or recieveing email from the internet while still allowing them to send and recieve email internally. Is there any way to do this on a user by user basis?

[Klug]

Hello, welcome to the forum.

This is not possible (yet) inside Zimbra.
If you search the forum and wiki, you'll find some ways of achieving it.

Here for example : http://wiki.zimbra.com/index.php?tit...ertain_domains

[gking]

Ok, I'm fine with doing it in postfix.

[Klug]

Beware doing it in the Zimbra's postfix might lead to "issues" (setup erased by upgrade, etc). I think it's better to do it on a smarthost/relay.

[gking]

Ok, I can do that too. Thanks for the tip.

[tbullock]

What about depriving the Zimbra server of DNS resolution? It should still be able to resolve it's own internal domains, but if it had no way of resolving external domains then no messages would leave your site.

[gking]

Well yes, I've fudged it in a similar fashion at the moment by firewalling off port 25. However in the long term I will have users who will need external access along with ones who do not. So I'll have to go with controlling it on a smart host.