SC-7(4) External Telecommunications Services

Implement a managed interface for each external telecommunication service;

Establish a traffic flow policy for each managed interface;

Protect the confidentiality and integrity of the information being transmitted across each interface;

Document each exception to the traffic flow policy with a supporting mission or business need and duration of that need;

Review exceptions to the traffic flow policy [Assignment: frequency] and remove exceptions that are no longer supported by an explicit mission or business need;

Prevent unauthorized exchange of control plane traffic with external networks;

Publish information to enable remote networks to detect unauthorized control plane traffic from internal networks; and

Filter unauthorized control plane traffic from external networks.