Help! Need bandwidth auditing tool

I have a dedicated server with ServerCentral.net. My monthly bill is normally $175 per month. But it's been crazy in the past two months; I just got my bill saying that I was charged for $625 in November!

Something's got to be using up a lot of bandwidth on my server, but I'm not actually sure what. Does anyone have suggestions on a good tool that will track where my bandwidth is going and generate a nice, easy-to-read report for me?

 

 

 

 

Top