Sounds very suspicious to me. Almost like you've been hacked .

I would post a HJT in the Virus forum.

Thanks.

I agree that it sounds suspicious, but please give us some details on the above statement if you can.

* What returns the pattern; how are you monitoring your network activity?

* Exactly what "pattern" are you referring to?

* Can you give us any details on the history of this activity?

Well I first noticed it when playing Quake2. I use netgraph (a Quake 2 command) from time to time to monitor the data flow in the game. Then I saw every time, it had a red bar in it for about 0.5 seconds and the game would freeze up completely. It also has a following pattern of 2 or 3 humps that happens every now and then which make the game lag terribly. So I downloaded netgraph (a free tool) and I used it to check what was going on. It seemed that with the red bar in Quake 2 It would be downloading a lot, and with the green humps it would be uploading a fair amount.

About the netgraph command:

netgraph
Type: Toggle

Default: 0

Description: Toggle the display of the network performance graph.

Note: The size of each bar is the latency time. A green bar indicates a successful packet transfer. A red bar indicates a lost packet.

Do the bursts of network activity occur only when Quake is running, or do they happen during other online activities as well?

They always happen, even when I'm doing nothing.

I've found that the info gathered from a firewall program like Sygate Personal Firewall (freeware) is very useful in terms of determining what exact applications/programs/processes are communicating over the network, what destination IPs they're communicating with, and which ports/protocols they're using.

If you temporarilly install Sygate just for investigation/troubleshooting purposes, I'm sure it will tell you a lot about what's going on with your network traffic. I wouldn't recommend leaving it installed on a gaming machine though, as firewall programs can introduce network latencies/lags which can interfere with smooth gaming performance.

There is, of course, the possibility that a malicious infection is responsible for the traffic. If you haven't ruled out that possibility yet, you should do so now. You can find useful resources on that in many of the threads in our malware forum .

Well, I've reinstalled the system, so I don't think that's the problem.

You don't think what is the problem? Infections?

Indeed, I think it might have to do with the networking equipment.