SC-7(4) Boundary protection | external telecommunications services
What the standard requires
(a) Implement a managed interface for each external telecommunication service; (b) Establish a traffic flow policy for each managed interface; (c) Protect the confidentiality and integrity of the information being transmitted across each interface; (d) Document each exception to the traffic flow policy with a supporting mission or business need and duration of that need; (e) Review exceptions to the traffic flow policy [frequency] and remove exceptions that are no longer supported by an explicit mission or business need; (f) Prevent unauthorized exchange of control plane traffic with external networks; (g) Publish information to enable remote networks to detect unauthorized control plane traffic from internal networks; and (h) Filter unauthorized control plane traffic from external networks.
Quoted verbatim from NIST SP 800-53 Rev 5 (OSCAL catalog), which is in the public domain.
Cross-framework mappings
No cross-framework mapping is seeded for this control. That is stated rather than filled in: a mapping nobody authored is worse than a gap you can see.
In CMDash this control is a row with an owner, a status, uploaded evidence kept with its full history, and an export an assessor can read.