SC-7(4): External Telecommunications Services

Control Statement

1. Implement a managed interface for each external telecommunication service;
2. Establish a traffic flow policy for each managed interface;
3. Protect the confidentiality and integrity of the information being transmitted across each interface;
4. Document each exception to the traffic flow policy with a supporting mission or business need and duration of that need;
5. Review exceptions to the traffic flow policy [Assignment: organization-defined frequency] and remove exceptions that are no longer supported by an explicit mission or business need;
6. Prevent unauthorized exchange of control plane traffic with external networks;
7. Publish information to enable remote networks to detect unauthorized control plane traffic from internal networks; and
8. Filter unauthorized control plane traffic from external networks.