A network security domain is a contiguous region of a
network that operates under a single, uniform security policy. Whenever domains
intersect, there is a potential need for security to control traffic allowed
into the network. Firewall technology can be used to filter this traffic. The
most common boundary where firewalls are applied is between an organization’s
internal network and the internet. This report will provide readers with a
resource for understanding firewall design principles used in network security.