CISSP For Dummies, 4th Edition

Network Security

Network security is implemented with various technologies, including firewalls, intrusion detection systems (IDSs) and intrusion prevention systems (IPSs), remote access authentication mechanisms, and Virtual Private Networks (VPNs).

Intrusion detection systems (IDS) and intrusion prevention systems (IPS) are sometimes referred to as intrusion detection and prevention systems (IDPS).

Firewalls

A firewall controls traffic flow between a trusted network (such as a corporate LAN) and an untrusted or public network (such as the Internet). A firewall can comprise hardware, software, or a combination of both hardware and software. The CISSP candidate must understand the various types of firewalls and common firewall architectures.

Firewall types

Three basic classifications of firewalls have been established: packet-filtering, circuit-level gateway, and application-level gateway.

Three basic types of firewalls are packet-filtering, circuit-level gateway, and application-level gateway.

Packet-filtering

A packet-filtering firewall (or screening router), one of the most basic (and inexpensive) types of firewalls, is ideally suited for a low-risk environment. A packet-filtering firewall permits or denies traffic based solely on the TCP, UDP, ICMP, and IP headers of the individual ...