Server is constantly working hard without any traffic
I've setup an older box (p3, 512Mb, 20G hd) following exactly every step in the HOW TO SETUP a Web Server with Fedora Core 4. I know that FC4 is really meant to be used with newer machines, but it was / is working fine except... the 2nd day the box was running, it started working its butt off for no real apparent reason. Emails all of a sudden took 8 hours or more to be delivered into the test account I had setup in ISPConfig. The only 3 things that I could think of - that would maybe cause this, were either from Postfix's log writing, apt-get updating or someone attacking my machine (however unlikely)... So I first disconnected my connection to the internet and still had the same problem, I stopped the apt-get schedule... same story... but after I shutdown postfix voila!... the system seemed to work fine again. As I'm a newbie to running a web server on a Linux box (used XAMPP on an XP machine to put sites together for people), I need some help! What could be causing this? I need to be able to host my own sites on my own machine for various applications...