There's a growing number of companies eager to make a profit by selling hardware that filters Skype and/or p2p traffic. In China it's a particularly hot market, the government run Shanghai Telecom employing the use of hardware by Narus in an effort to eliminate VoIP competition. But is Skype really so easily blockable?

According to this article over at Extreme VoIP by the CTO of packet shaping hardware vendor APConnections, blocking the softphone isn't quite so easy. "To date all my common tricks for determining VOIP traffic on the Internet have been thwarted by the Skype designers. I have no idea if this result was a deliberate attempt to thwart detection or just an unintended side effect of their design," he says.