Fortinet has released a new anti-virus engine for its security appliances, two months after US authorities ordered it to stop using the previous version of the software.

In August, the International Trade Commission ruled in favour of Trend Micro in a year-long patent infringement suit, requiring Fortinet to suspend its sales in the US.

The company has since written its own scanning engine to comply with the ruling, even going as far as to file a new patent for it with the US patent office. The company hailed its latest engine - which will find its way on to customer hardware as a firmware upgrade - as "groundbreaking new technology".

"Fortinet’s new anti-virus engine has undergone external legal and industry expert analysis, both of which determined it did not infringe the patent claims at issue in the related 8 August, 2005 ITC orders," the company release said.

"The result is innovative technology that revolutionises anti-virus security and performance within our flagship FortiGate security appliances. While we stand firmly in our position that our technology did not infringe on Trend’s patent, we are following ITC orders and have already resumed business as usual," continued company CEO and founder, Ken Xie.

In fact, the Trend Micro patent dispute is the second such problem to assail the company in recent times. Last April, the company was forced to settle a patent infringement dispute relating to use of the GNU General Public License (GPL) code in a case brought against Fortinet UK by Harald Welte of

As Welte said at the time. "This violation by Fortinet is especially egregious since the vendor not only violated the GPL, but actively tried to hide that violation."