High network activity while running Xcode, could it be a virus?

I use osx86 to develop software. I download and install iantares v2.2 (snow leopard 6.3.3) and xcode 3.2.3 with ios sdk 4.0 dmg. When I use xcode open my project and build it, I find the light on router begin flash, after I close xcode, the light stops flash. If I only open xcode and open my project, the router light won't flash, it flashes only when I build my project.

I google on the net and find nothing about virus or trojan with xcode,开发者_Python百科 but how to explain what I see?

You're using pirated software, from a third party source, installed in contravention of its licence agreement. So don't rule out a trojan.

That said, it's more likely Xcode's distcc-related distributed build feature. It's probably just looking for other machines to distribute the workload with; at least in Xcode 4 you get to pick whether your machine will help others but I can't see anything obvious to disable it looking for help for itself.

You may want to ask a question on Serverfault regarding troubleshooting network activity.

If your "router light" is "flashing", there are so many possible causes. You would need something like Wireshark to begin to diagnose what is happening on your network. It's most likely as zoul suggests, an update or a licence check or something similar that Xcode is performing. Also, most likely nothing to worry about.

Link to Wireshark