I do not know if this is a Postfix bug or a Virtualmin Pro bug, but we ran into a problem on fresh installs on Ubuntu 8.04 LTS for sending emails from PCs on the servers.
This worked fine with Debian but not with Ubuntu.
We installed just barebone ubuntu + update/upgrade + wget + install.sh virtualminPro So Virtualmin's install.sh installed postfix.
We got SASL failures in Postfix when sending from PCs and macs using TLS.
After quite some research, we found this thread: http://www.howtoforge.com/forums/showthread.php?t=22730
and adding postfix to sasl group fixed the problem instantly:
adduser postfix sasl /etc/init.d/postfix restart
Looks like it's needed. Not sure if there are any security implications here.
But if not done by Virtualmin, it should be at least part of virtualmin checks....
1) Is that ok security-wise ? 2) if you could fix that in virtualmin, it would avoid sleepless nights for sure :)