Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
This is a detailed description about the steps to be taken to setup a Ubuntu based server (Ubuntu 5.0.4 - The Hoary Hedgehog) that offers all services needed by ISPs and hosters (web server (SSL-capable), mail server (with SMTP-AUTH and TLS!), DNS server, FTP server, MySQL server, POP3/POP3s/IMAP/IMAPs, Quota, Firewall, etc.).
In the end you should have a system that works reliably and is ready for the free webhosting control panel ISPConfig (i.e., ISPConfig runs on it out of the box).