<snip> 1) I am migrating email from a Win32 environment to a *nix based environment. :) I am working with people that I have to remind that Linux is not a singular all-encompassing distro (ie: that Linux does means Linux but rather SuSe, Redhat, Mandrake etc..) 2) It must be ultra-secure. 3) Large scale means over 1,500 mail boxes and approx 350 to 400 domains. <snip> Thank you to everyone that took the time to reply. I have a lot of reading ahead of me but I can at least say that so far I have chosen to go with OpenBSD. I have installed the OS on a test computer and I'm tinkering as much as possible right now. - Michienne