On September 6, 2006, the District Court in Frankfurt-on-the-Main issued a judgment which upheld the validity of the GNU General Public License (GPL), version 2.   The case involved a complaint by Harald Welte, a co-developer of the netfilter firewall code in the Linux kernel and founder of the gpl-violations.org project, against D-Link Germany GmbH, a German subsidiary of Taiwanese hardware manufacturer D-Link Corporation.

D-Link used the Linux kernel and various other GPL-licensed programs in its firmware for an NAS device, but did not provide a copy of the GPL license or make the full source code of the software available, both of which are conditions to the right to modify and distribute GPL licensed software. After receiving a warning notice from Mr. Welter complaining of GPL violations related to three specific GPL-licensed software programs, D-Link agreed to cease and desist from its practices, published the firmware source code and informed the buyers of the server of the GPL violation. However, D-Link refused to admit violating the GPL or to reimburse Mr. Welter for his costs in sending the warning notice or for buying a unit and having the firmware examined to confirm it was using GPL-licensed software.

Consistent with the May 2004 decision of the District Court in Munich I, which upheld  a temporary injunction against the router manufacturer Sitecom for GPL violations (opinion [German], translation), the Frankfurt-on-the-Main court held the GPL was essentially valid and enforceable. In particular, the court held that “the provisions of the GPL cannot be read as relinquishing copyright or copyright-law legal positions” and that, pursuant to Section 4 of the GPL, the failure by D-Link to comply with the conditions of Section 2 of the GPL meant that it lacked any right to distribute the GPL-licensed software and violated copyright law by doing so.

The court rejected D-Link’s argument that the plaintiff could not bring the case because he was not the sole developer of the software programs in question, that in fact he had stopped developing the program and that other free software developers had greatly expanded upon it, ruling it sufficient that the plaintiff had written the initial code on which the subsequent improvements were based. The court also rejected D-Link’s argument that the GPL violated antitrust laws via price fixing, holding that if the GPL did indeed violate antitrust laws, the entire license would be void and D-Link would lack the right to distribute the copyrighted, but GPL-licensed, software.

The judgment awarded the Mr. Welter his costs for test purchasing a server and examining it, as well as for his legal fees and expenses in bringing the claim. The opinion is available online [German]. D-Link has reportedly indicated it will not appeal the ruling.