my preferred mail installation would be to use the qmail package patched with john simpson's combined patch, authenticating against vpopmail. This way of doing things encourages security by default, with the login command only allowed to be transmitted once the user is on a secure (SSL/TLS) connection.
See qmail.jms1.net for details on this patch and the JMS way of doing qmail virtualhosting.
Is there any way of safely migrating away from the configured postfix system on my CENTOS system to my own custom build of qmail the JMS way? I'm prepared to reconfigure my system from scratch if there's no easy way of doing the migration, as I haven't opened the server to the public yet (It's only handling a couple of personal sites and my personal email atm).
the other question, will virtualmin mind if I completely remove the postfix/dovecot rpms, or will it reinstall them on each subsequent upgrade?