(Corrects 4th paragraph to show that NCCIC is in Virginia, not Maryland)
BOSTON, July 23 (Reuters) - Larry Zelvin, the head of the U.S. Department of Homeland Security's center for countering cyber threats, is retiring next month after a government career of nearly 30 years during which he advised U.S. businesses on fighting hostile hackers.
Zelvin helped coordinate efforts to advise U.S. banks as they responded to denial of service attacks believed to have originated from Iran, which disrupted their websites in recent years.
He also assisted U.S. retailers looking to prevent cyber attacks on their point of sales systems after last year's unprecedented breach at Target Corp.
A spokesman said a successor has not been named to run the agency's National Cybersecurity and Communications Integration Center (NCCIC) in suburban Virginia, which helps government agencies and private firms identify and respond to cyber attacks.