First off, I am a newbie at Linux, although I've been running a WAMP webserver for a couple of years on Windows Pro XP SP2. I have four websites running on this server, along with a hMailServer for three of them. I currently use ZoneEdit.com for DNS forwarding for all sites. Although the Windows setup is working fine, I would like to move everything to a Linux server for security reasons (I've had my mail server hijacked a couple of times). The server resides in my home behind a router/gateway, and I use ADSL through the phone company for internet access. I do have a static IP address through the phone company. I just installed "The Perfect Server" using Ubuntu 7.10, following the instructions on HowtoForge, and installed ISPConfig to manage the various virtual sites. I'm having trouble with the mail server piece. I am able to send mail from one user at mydomain.com to another user at mydomain.com, but mail to/from external addresses is not getting delivered or received, and I have no idea what I may have set up wrong that is causing this to happen (this is not a problem on the Windows machine). I've been working on this for almost a week now, and am no closer to solving this issue now than I was when I started. Any assistance here would be most greatly appreciated. I'll post any log or configuration files that you tell me to post. Help!