5.1 So many choices!

A firewall is a system designed to control access to applications on a network, typically access to a private network from the public Internet. We know that when we connect to the Internet or any outside entity, we need a firewall. There are many different choices when it comes to defining the topology, selecting the vendor, and selecting the type of firewall.

There are three main types of firewall software and hardware configurations:

1. Packet filtering

2. Proxy server or application gateway

3. Circuit-level gateway or generic application proxy

This chapter will help you assess the main types of firewall architectural options. In addition, an evaluation checklist exists for selecting firewall vendor solutions.

There are several reasons why we need a firewall:

• Loss of mission-critical business information

• Loss of services such as e-mail, HTTP, FTP, and EDI

• Protection of legal and confidential information

• Prevention of exposure to network servers and workstations

• Enforcement of security policies

Will firewalls solve all of your security problems? No, but they do provide a needed level of security. They do not, however, protect against users accidentally revealing a password, computers within an organization connecting to a phone that is not protected from the firewall, or insider attacks. Over 50% of all security breaches occur from insiders. Not all firewall products check incoming code for signs of viruses and Trojan horses. You will still need to implement hardware level security, OS security, application security, and solid policies and procedures. Even though they are not a...