Which of the following is by far the most common prevention system from a network security perspective?

A. Firewall

B. IDS

C. IPS

D. Hardened OS

E. Tripwire

F. None of the choices.

Explanation:

User account access controls and cryptography can protect systems files and data, respectively. On the other hand, firewalls are by far the most common prevention systems from a network security perspective as they can shield access to internal network services, and block certain kinds of attacks through packet filtering.