Implementing Cisco Networking Solutions

Introduction to firewalls

A firewall is a device that protects networks from unauthorized access by users from other networks. The networks are assigned to security zones and policies are configured to explicitly allow or block communications between the different networks. An organization would place the internet facing servers in a zone that connects to the internet, allowing traffic for specific applications, and the remaining servers would typically be placed in zones that are not accessible from the internet. The zone that connects to the internet is typically called a demilitarized zone or a DMZ. The other zones depend upon the security design of the organization. Typical names used for the other zones are the application zone, the ...