With the newly implemented bandwidth cap policy at Comcast I, like many others, am starting to pay closer attention to my bandwidth usage. During a period of relative inactivity I noticed my monthly usage increasing at a rate that seemed inconsistent with my actual usage. I discovered that there is a constant stream of incoming data 24/7, at a fairly consistent rate of approximately 512 kbit/s (64 KB/s). This stream will chew up 5.5 GB per day, or 165 GB per month! I have a WRT54GS running Tomato 1.21, and I am using the router's bandwidth monitor. My first attempt was to determine which device in my network was responsible for this traffic, but I found that with hard wired devices disconnected and wireless networking disabled, the incoming traffic continues. I am a bittorent user, and started to think that what I was seeing might be a stream of incoming connection requests. To test this theory I changed my IP address. Before and after tests with whatsmyip.org confirmed that my IP address was successfully changed, but the traffic persisted. Finally, I connected one of my machines directly to the cable modem, bypassing the router, and monitored bandwidth using DU Meter. To my surprise, DU Meter showed negligible incoming traffic, which stayed around 5 kbit/s. Now I'm totally confounded. I am desperate to identify what the source of this traffic is and assess what I can do to eliminate or at least limit it. Any suggestions would be greatly appreciated!