SC-7 (5) - Deny by Default — Allow by Exception
Control requirements
SC-7 (5) - 0
Deny network communications traffic by default and allow network communications traffic by exception [IBM Assignment: any systems].
NIST supplemental guidance
Denying by default and allowing by exception applies to inbound and outbound network communications traffic. A deny-all, permit-by-exception network communications traffic policy ensures that only those system connections that are essential and approved are allowed. Deny by default, allow by exception also applies to a system that is connected to an external system.