Hardware firewalls, such as integrated routers, protect data and equipment on a network from unauthorized access. A hardware firewall is a free-standing unit that resides between two or more networks, as shown in the figure. It does not use the resources of the computers it is protecting, so there is no impact on processing performance.

A firewall should be used in addition to security software. A firewall resides between two or more networks and controls the traffic between them as well as helps prevent unauthorized access. Firewalls use various techniques for determining what is permitted or denied access to a network segment.

Considerations when selecting a hardware firewall include:

NOTE: On a secure network, if computer performance is not an issue, enable the internal operating system firewall for additional security. Some applications might not operate properly unless the firewall is configured correctly for them.