VirnetX announced on Thursday that it has filed a suit against Apple, Cisco, NEC, and Aastra, accusing them of infringement of five separate patents held by them.  Apple is targeted for an infringement by the iPhone, iPad and iPod touch for a patent relating to the VPN (virtual private networking) connectivity.

The company, one that runs patent portfolios through licensing fees and legal judgements, has a track record of suing Microsoft over violations, one in particular gained VirnetX $200 million and one of the two patents Apple is accused to have infringed on, is the same as the one in Microsoft's case.  Wednesday's suit claimed that Apple's iPhone, all models, including the newest iPhone 4, iPod Touch and iPad infringed a pair of VirnetX patents.  One of the two that Apple reportedly infringed (identified as Patent No. 6,502,135) was also one of the pair that VirnetX said Microsoft violated.

The patents broke were named "Agile network protocol for secure communications with assured system availability," which describes technologies for producing and maintaing a virtual private networking (VPN) connection.

The patent suit was filed with the United States District Court for the Eastern District of Texas, a place where many patent cases were filed.  The judge, Leonard Davis, presided in Microsoft's case and is known for ruling in the favor of the plaintiff in patent disputes.

Stay tuned for more developments with this developing story.