Linux Box As a Web/Mail/File Server

Hi friends.
I started this discussion for our all linux friends. to get the help on Linux Box. Lets start with proper tips and procedure of installation of Linux with Web Mail File DNS server… also we should talk on VPN on linux.
I would invite all experties. that post your knowlede and lets start to grow.
First topic will be configuration of an DNS.
Friends your time starts now…