For this who would like to run an exchange server or you just want a mail server running or you want to replace an MS Exchange Server, Scalix has got a GREAT replacement. I'm running the "Community" Edition which is not supported by Scalix, but has a community forum for which you get answers to issues almost immediately! The website is
http://www.scalix.com. They sell an Enterprise version of their software, but the Community Edition allows up to 5 "Enterprise Users" which allows you to install the Outlook MAPI connect software and keep you mail on the server, calendar, contacts and just about everything MS Exchange supports. It's also extremely easy to install. It patches your configuration files for needed packages (like sendmail) automatically.
I would highly recommend it to those who are interested in running an Exchange-like server. I also tried the "Openxchange" (I think thats the name) installation, but it was far more involved. I was downloading modules from here and there and had to configure them myself. Much more time consuming. So, I can't say that it's better or worse (functionaly) from Scalix because I got Scalix running first so I dropped the Open-xchange installation. I may try it one of these days just for kicks and grins.