Disabling client IP reverse DNS?

[Scott Balmos]

Hi all,

I know in a virtual domain setup, if a user connects with an unqualified 
username, the server does a reverse DNS lookup on the *server's* 
incoming connection IP, to determine a default virtual domain name.

But how do I disable Cyrus from doing a reverse DNS on the *client's* IP 
that they're connecting from? Connections to my mail server from home 
are taking very long because of a reverse DNS lookup being done on my 
home IP. This fails because my stupid cable Net ISP doesn't know how to 
run DNS properly. :)

Insight is appreciated. Thanks!

--Scott Balmos