NSPM, or Network Security Policy Management, is the practice of tracking, validating, and governing network security policy throughout its lifecycle. It helps security teams compare the policy they intended to deploy with the rules that are actually enforced on firewalls, routers, and other network controls.
This matters because networks change constantly. Temporary exceptions, manual edits, and configuration drift can weaken a control without anyone noticing. In cyber security, NSPM provides visibility into those changes, highlights mismatches between design and reality, and creates evidence for audits and compliance. Defenders use it to verify that segmentation, access rules, and other controls still work as expected; attackers benefit when policy drift leaves gaps or overly broad permissions in place.