The FCC lambasted Comcast (NSDQ: CMCSA) for blocking traffic from some P2P users and evading its official position on the matter in a long awaited and 3-2 split ruling today. Prompted by a complaint filed by Free Press and Public Knowledge and complaints from Comcast subscribers who noticed problems using P2P applications such at BitTorrent, Comcast denied responsibility at first and then changed its story at least three more times as new details emerged. “Comcast’s interference is far more invasive and widespread than the company first conceded,” the commission wrote in its ruling. The FCC didn’t fine Comcast but ordered it to cease all “discriminatory network-management practices” by the end of the year. Within 30 days, Comcast is required to disclose its practices to the agency. Release (pdf).

The ruling throws another monkey wrench into the network neutrality debate. Many bit-delivering companies have argued they should be able to block the distribution of non-copyrighted material on their network. Some have gone on the record saying they don’t want to be the police of the internet, but still where exactly the liability line falls is unclear.

More from the FCC ruling: “…Comcast has an anti-competitive motive to interfere with customers’ use of peer-to-peer applications,” which can deliver high-quality video content that users might otherwise pay for on cable TV. Calling Comcast’s tactics “invasive” and having “significant effects,” the commission wrote that it found the company is “monitoring customers’ connections using deep packet inspection and then determines how it will route some connections based not on their destinations but on their contents. In essence, Comcast opens its customers’ mail because it wants to deliver mail not based on the address on the envelope but on the type of letter contained therein.” The FCC believes Comcast “interfered with up to three-quarters of all peer-to-peer connections in certain communities.” The end result being the “blocking of internet traffic, which had the effect of substantially impeding consumers’ ability to access the content and to use the applications of their choice.” Still, the agency “reiterated that its interest is in protecting consumers’ access to lawful content. Blocking unlawful content such as child pornography or pirated music or video would be consistent with federal internet policy.”

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