Summary

Firewalls, regardless of how complex in design and implementation, have a simple responsibility to act as security policy enforcement points. Firewalls can do this by inspecting the data that is received and tracking the connections that are made to determine what data should be permitted and what data should be denied. In addition, firewalls can act as an intermediary and proxy requests to the protected host while at the same time providing a means of authenticating access to better ensure that only approved access is granted. Finally, firewalls can report and alert on events related to all of these processes to allow you, the administrator, to know what is going on with your firewall and the systems it is protecting.

Any number of motivations drive people to develop threats to our systems. By examining the threats and the appropriate responses, you can develop a security policy that minimizes the risk presented by a threat through the proper implementation and configuration of a firewall. Although a firewall cannot prevent all attacks, it is one of the best methods of protecting resources; and when in doubt, there is a good chance that a firewall can help make your resources even more secure than if there were no firewall at all.