computer network defense (security) (CND)
Computer Network Defense(CND) is part of Computer Network Operations (CNO). It also includes Computer Network Attack(CNA) and Computer Network Exploitation( CNE).
As far as Computer Network Defense is concerned, it is about measures with which computer networks are defended against attackers. These include monitoring critical entry points, analyzing vulnerabilities, and defending against and blocking attacks. One way of preventing attacks is penetration testing, which is particularly suitable for finding and assessing vulnerabilities that limit confidentiality and availability.