Tarpit (networking) - Commercial Implementations of Tar-pitting

Commercial Implementations of Tar-pitting

As well as MS Exchange, there have been two other successful commercial implementations of the tar pit idea. The first was developed by TurnTide, a Philadelphia-based startup company, which was acquired by Symantec in 2004 for $28 million in cash. The TurnTide Anti Spam Router contains a modified Linux kernel which allows it to play various tricks with TCP traffic, such as varying the TCP window size. By grouping various email senders into different traffic classes and limiting the bandwidth for each class, the amount of abusive traffic is reduced - particularly when the abusive traffic is coming from single sources which are easily identified by their high traffic volume.

After the Symantec acquisition, a Canadian startup company called MailChannels released their "Traffic Control" software, which uses a slightly different approach to achieve similar results. Traffic Control is a semi-realtime SMTP Proxy. Unlike the TurnTide appliance, which applies Traffic Shaping at the network layer, Traffic Control applies traffic shaping to individual senders at the application layer. This approach results in a somewhat more effective handling of spam traffic originating from Botnets because it allows the software to slow traffic from individual spam zombies, rather than requiring zombie traffic to be aggregated into a class.