Firewalls

not allow for a uniform “drop-in” installation setup, so every private

network administrator should research the topic of firewalls and

network security to find a personalized solution or type that best fits

their needs. This chapter should not be used as a replacement for

knowledgeable network or security administrators.

3.2 Types of firewalls

Conceptually, there are three types of firewalls. Now, let’s start off

with a brief review of all three of the basic firewall types:

■ Simple packet filtering: IP or filtering firewalls—block all but

selected network traffic

■ Application-layer firewalls: Proxy servers—act as intermediary to

make requested network ...