Writing to the D.C. Circuit Court of Appeals, the FCC defended its findings last year that Comcast improperly interfered with the right of web users to access lawful content by throttling, or selectively blocking, high-bandwidth file transfers emanating from the BitTorrent site, arguing that the agency’s actions constitute a proper exercise of ancillary authority. In a brief that responds to Comcast’s pending appeal of the FCC’s November 2008 order, the FCC challenged Comcast’s claim that the FCC lacked the authority to enforce the 2005 net neutrality principles at the heart of the BitTorrent case. Citing those principles, the FCC ordered Comcast to cease the practices in question, to disclose fully its network management practices to the FCC, and to file a compliance plan with the agency. Pointing to the U.S. Supreme Court’s decision in National Cable & Telecommunications Association v. Brand X, the FCC said the high court concluded that, “although information service providers are not subject to mandatory regulation by the Commission, the FCC has authority over them under its Title I ancillary jurisdiction.” The FCC further claimed that its actions with respect to Comcast are ancillary to Section 230(b) of the 1934 Communications Act, in which Congress “set forth various [policies] of the United States regarding the Internet, including a policy of maximizing user control over the receipt of Internet content.” As such, the FCC asserted: “it is settled law that the agency may exercise . . . jurisdiction over matters not directly addressed by the Communications Act—ancillary authority—where doing so furthers regulatory goals that are based in the provisions of the Act.” Notwithstanding such authority, the FCC also told the court that, when the FCC approved cable system transfers to Comcast several years ago, Comcast was warned by the FCC “that any interference by Comcast with its customers’ access to Internet content and applications would be assessed under the standards of the [2005] Internet Policy Statement.”