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.

The protest was filed with the Government Accountability Office and is dated Oct. 5.

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 an additional two years.

“The DOMino contract will provide services to operate and maintain existing EINSTEIN capabilities and will also be used to design and develop new cyber security capabilities for the NCPS,” DHS spokesman SY Lee said in a statement provided to HSR last month. “Although federal government agencies are responsible for their own cyber security, the Department of Homeland Security has the mission to provide a common baseline of security across the government and help agencies manage their cyber risk. Through the department’s National Cybersecurity Protection System, which includes EINSTEIN, DHS prevents known or suspected cyber threats using an integrated system of intrusion detection, analytics, information sharing, and intrusion prevention capabilities.”