Network Security, Firewalls, and VPNs, 3rd Edition

CHAPTER SUMMARY

An essential element of network security, a firewall is a filtering service used to protect your network and hosts from a variety of threats, both internal and external. Several types of firewalls are available, including screening routers, hardware appliances, and host software products. Each of these firewalls can employ one or more features for ingress and egress filtering. The common filtering features include static packet filtering, stateful inspection or dynamic packet filtering, NAT, application proxy, and circuit proxy.

Firewalls are useful in many different situations. Every network infrastructure can benefit from proper use of a firewall. When making a choice about which firewall to deploy, consider a breadth ...