Only authorized personnel with appropriate clearances are granted physical access to computing facilities that process classified information.
MAC / CONF
Physical and Environmental
Servers, workstations and documentation located in secure facilities are at risk of attack, copying, destruction, and illegal distribution by unauthorized access.
1. All locations where servers, workstations and documentation containing classified information shall be prohibited to those who do not have adequate permissions to enter such facilities. 2. Access to these facilities shall be granted to those personnel only after receiving a background investigation and granted approval for access to classified information.
DoD 5200.2-R, (Personnel Security Program), January 1987