Northrop Grumman [NOC] has protested the award of a potential $1 billion contract that Raytheon [RTN] won in September from the Department of Homeland Security (DHS) for support of a network security program.iStock Computer

The protest was filed with the Government Accountability Office and is dated Oct. 5. GAO says it expects to adjudicate the protest by Jan. 13, 2016.

Raytheon won the Development, Operations and Maintenance (DOMino) services contract to provide support to the DHS National Cybersecurity Protection System (NCPS), which includes EINSTEIN as its operational component. General Dynamics [GD] was the original contractor for support of EINSTEIN to provide defense of federal networks at the perimeter.

Under DOMino, Raytheon–or possibly another contractor should Northrop Grumman’s protest be upheld–will provide defense inside networks. DHS uses the NCPS to prevent known or suspected cyber threats using an integrated system of intrusion detection, analytics, information sharing, and intrusion prevention capabilities, according to DHS.

The DOMino contract is for five-years and has provisions to extend some orders for and additional two years.