From: "Vince Van De Coevering" <vpv at figaros dot com>
> Or take the easy road and swap DNS hosting with someone else...
> Zone transfers can be encrypted, password protected, and restricted by IP
> BIND will notify slave servers when the domain has changed.
I second this. Additionally if a mailserver is down, a sending mail
programs may handle it different than a mailserver with a failed DNS query.
You may loose more mail the other way.