Which agency manages the Defense Information Network (DISN) and associated subdomains?

• A. Defense Information Systems Agency (DISA)
• B. National Security Agency (NSA)
• C. Central Intelligence Agency (CIA)
• D. Department of Homeland Security (DHS)

Answer: (A)

The Defense Information Systems Agency is the entity responsible for the Defense Information Network and its subdomains. DISA serves as the DoD’s combat-support agency for information technology, communications, and cyber operations, delivering and securing the network infrastructure that links all DoD components. Because DISN is the DoD’s global, secure communications backbone, its management falls to DISA, which handles network provisioning, cybersecurity, and enterprise services across the department.

The other agencies have different primary roles: the NSA focuses on signals intelligence and information assurance, the CIA handles foreign intelligence, and DHS oversees civilian homeland security. None of them administer the DoD’s DISN and its subdomains.