[Dovecot] No tcp wrappers, other ideas to help stop brute force attacks?

I'm looking for a way to deny access to dovecot from certain IP addresses, basically to help prevent brute force attacks on the server.

Right now I'm using denyhosts which scans /var/log/secure for authentication failures which then can add an entry to /etc/hosts.deny, but since dovecot doesn't have tcp wrappers support, that doesn't do anything.

It doesn't look like I can run dovecot run xinetd.

Any other ideas to help protect dovecot from brute force attacks? I don't think pam can help, can it?

Otherwise I need to figure out a way to have denyhosts trigger iptables rules or something, or maybe there's another application that will work?

-Dave