The Electronic Frontier Foundation (EFF) has released a report (PDF) containing analysis of Comcast's Internet traffic interference activities. The EFF's study provides strong evidence that Comcast is using packet-forging to disrupt peer-to-peer (P2P) filesharing on their network.

According to the report, the EFF used an open-source packet sniffer called Wireshark to analyze network traffic while attempting to seed public domain literature on BitTorrent with a Comcast broadband connection. The tests confirmed that BitTorrent performance was being selectively degraded by unexpected TCP reset packets. Previous independent research conducted by the AP is consistent with the findings published by the EFF.

"Initial investigations suggest that Comcast is interfering with some subset of protocols, rather than interfering equally with TCP/IP traffic generally," the EFF's study says. "We have seen definite interference by injection of RST packets into certain classes of BitTorrent and Gnutella TCP sessions."

Although Comcast has admitted to using traffic management technologies, the company still continues to insist that it does not target specific protocols or technologies despite mounting evidence of BitTorrent disruption. Advocacy groups have filed a complaint with the FCC, characterizing Comcast's behavior as a flagrant violation of the network neutrality principles outlined in the FCC's Internet Policy Statement. Comcast's critics are calling for the FCC to instate a permanent ban on P2P interference and impose massive fines on the company. Comcast's competitors, who have traditionally expressed opposition to network neutrality, are also advocating an FCC investigation. Additionally, allegations of traffic blocking have led to class-action lawsuit that was filed earlier this month.

Comcast executive vice president David Cohen told us that Comcast does not block access to BitTorrent and that the company's traffic control mechanisms are permissible because the FCC's standards explicitly permit "reasonable network management" practices. The FCC has not yet stated how it will respond to Comcast's P2P interference.

Comcast has been extremely secretive about the scope and extent of its traffic management activity. The company provided instructions to its employees specifying how they should respond to consumer questions about P2P interference. Employees were informed that discussing the specifics of Comcast's P2P blocking with anyone outside of the company would lead to termination.

In addition to providing evidence of network interference, the EFF study also explains how Comcast's selective degradation of BitTorrent traffic undermines future Internet innovation. "The Internet has enabled a cascade of innovations precisely because any programmer—whether employed by a huge corporation, a startup, or tinkering at home for fun—has been able to create new protocols and applications that operate over TCP/IP, without having to obtain permission from anyone," the EFF wrote. "Comcast's recent moves threaten to create a situation in which innovators may need to obtain permission and assistance from an ISP in order to guarantee that their protocols will operate correctly. By arbitrarily using RST packets in a manner at odds with TCP/IP standards, Comcast threatens to Balkanize the open standards that are the foundation of the Internet."

The EFF also published a second report (PDF), which provides detailed technical instructions explaining how to use Wireshark to reproduce their study and test for ISP packet injection.

Proponents of network neutrality legislation point to Comcast's P2P blocking to support their argument that the current regulatory system isn't capable of providing consumers with sufficient protection from discriminatory network manipulation. Network neutrality supporters have long argued that the lack of competition in the broadband market makes it possible for Internet service providers to abuse their network control with impunity in the absence of stricter regulation. The FCC's response to widespread allegations of Comcast P2P blocking will indicate whether or not the current system has adequate safeguards.