An Easy Way to Block/Interfere with Skype?

Art Reisman CTO By Art Reisman

I got a call from a customer the other day who claimed that their NetEqualizer was working great except that it was interfering with their Skype calls, and he wanted us to make it stop.

Upon further investigation, we determined the NetEqualizer was  not interfering with his Skype calls at all. And then it hit me…His upstream ISP must be interrupting them. I can’t be sure of this, but there really was no other explanation. His access was good and we checked a couple of Skype calls and their bandwidth load was well below the threshold of anything the NetEqualizer would touch by design.

Then I had another “Aha!” moment while looking at their Skype streams on our built-in sniffer. The calls seemed to stay fairly steady in a tight range around 16kbs. It would be very easy and low cost to target streams in this range and periodically drop some packets, enough to make the call sound horrific while leaving any non-streaming media in that bandwidth range alone. I have no intention of tweaking our NetEqualizer to fill this mission,  however I did some quick research on the subject and did not come up with anything to make me think it would not work. If you are a Skype geek feel free to comment.

To add some context, here’s a link to an article I wrote a while back on the subject of blocking Skype: Blocking Skype Won’t Be Easy.

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