The Free Software Foundation has filed a copyright infringement complaint against Cisco Systems. The complaint alleges that Cisco’s Linksys products contain certain works in which the FSF holds the copyright, but Cisco has not complied with the requirements of the licenses pursuant to which the FSF makes the works available.

This is the first copyright infringement action ever filed by the FSF, according to the press release announcing the filing of the action. The filing of the lawsuit follows on the ruling by the United States Court of Appeals for the Federal Circuit last August in Jacobsen v. Katzer that open source licenses are enforceable under copyright law.

There are so few judicial opinions dealing with open source licenses that any single one is of great interest, but the pro-open source ruling of the Court of Appeals for the Federal Circuit in Jacobsen v. Katzer, No. 2008-1001 (Fed. Cir. Aug. 13, 2008) easily goes to the top of the charts of this small category. This is a highly significant opinion that will greatly bolster the efforts of the open source community to control the use of open source software according to the terms set out in open source licenses.