Block IPs that Don't Resolve via Reverse DNS Lookup

[eatickets]

I'm sure I'm not the only one who's tried to do this, but I've checked the forums and Google and couldn't find any instructions or documentation on this one: is there any way to tell Zimbra to block email from any IP address that doesn't resolve via a reverse DNS lookup?
I'm running ZCS Version 6.0.14_GA_2928.NETWORK on Ubuntu 8.04.

[gvillaran]

I think there is a check button to do that in the MTA tab in Global Settings?

[eatickets]

[quote user="gvillaran"]I think there is a check button to do that in the MTA tab in Global Settings?[/QUOTE]
I found a "DNS Settings" section. I'm assuming the setting you're thinking of is the check box for "Sender's domain (reject_unknown_sender_domain)"?

[gvillaran]

yes, thats the option i was thinking about.
is that what you want?

[eatickets]

That's probably what I want, but I'm not entirely familiar with how the "reject_unknown_sender_domain" command works, so I want to make sure this will fulfill my original request before I implement it.

[gvillaran]

Well if i send an email from isme@mydomaindontexist.com it will be rejected if the domain "mydomaindontexist.com" doesnt exist.
simple.

[eatickets]

But, is that the same thing as an IP address not resolving to a domain via reverse DNS lookup? It sounds like it is, but I want to make sure.

[eatickets]

Also, can anyone give me the likelihood of legitimate email being blocked with this reverse DNS lookup feature enabled?

[Yves Pires]

bad mail server setup

[eatickets]

[quote user="Yves Pires"]bad mail server setup[/QUOTE]
What do you mean by this?