Hi!
I'm very new to linux and was wondering what tools to monitor/control network/network usage do you guys use?
Specificaly are there any tools that would display in real time what program connected to what IP and most important how much bandwidtch (speed) is it using? Something like "top" but for network?

The reason I need this is because I have very wierd upstream spikes about every 15-30 minutes on default FC4 installation. At the beginning I thought it was my website, so to test it, I temporary disabled it but these spikes didnt stop, which left me clueless which service does it...Maybe somebody can help?

Thank you.

I tend to use iptraf:
http://iptraf.seul.org/

Thank you for your responce.
This is very usefull tool, indeed, but unfortunetly it does not show what service is using network at the moment...

At least it shows the port numbers (they become 2nd nature after a while).
And if you don't know what it is, just go to another terminal
$ grep portnum /etc/services

I haven't tried it, but how about nstats?
http://trash.net/~reeler/nstats/