Strange Skype Network Activity - Even on Linux

I have a few contacts with whom I still chat on Skype, so I still start it from time to time. Yesterday I started it in the morning, and then got distracted and forgot to stop it when the person I was looking for was not around (at least according to Skype's totally unreliable presence reporting). When I went back upstairs in the evening, I noticed the that the 5GHz LED and the Internet LED on my shiny new Netgear WNDR 3300 Wireless Router were blinking like crazy, and I really mean like crazy. I knew that there shouldn't be anything happening on my home network at that time, so I started investigating.

It quickly became apparent that the only thing that was running was Skype, which I had forgotten, running on my laptop under Mandriva Linux. I stopped Skype, and the internet activity stopped immediately. GRRRRRR! What the heck was going on? Skype has said, many times, that a system located behind and NAT router (network address translation) would not be chosen for use as one of their "SuperNodes", but it certainly appears that this is what had happened. Another possibility would be some sort of Skype virus or worm? Or perhaps the rumored, and still not confirmed or denied, Skype Back Door? The last time something similar to this happened, Skype was continuously eating CPU power on every system it was installed on, and that time Skype "explained it away" with a totally lame "oh, we forgot and left some debug code in the production release". Is this something similar?

The moral of the story is, if you still use Skype, keep an eye on your network activity, and don't believe any of the claims that they make about SuperNode selection, back doors, debug code, or anything else.

jw 18/8/2008