Marcus J. Ranum, American computer scientist and author
Marcus J. Ranum (born November 5, 1962, in New York City, New York, United States) is a computer and network security researcher. He is credited with a number of innovations in firewalls, including building the first Internet email server for the whitehouse.gov domain, and intrusion detection systems. He has held technical and leadership positions with a number of computer security companies, and is a faculty member of the Institute for Applied Network Security.