Firewall

A software utility and/or hardware device that limits outside network access to a computer or local network by blocking or restricting ports. Firewalls are a great step for helping prevent un-authorized access to a company or home network. The image to the right is a 3Com SuperStack 3 Firewall, an example of what a hardware firewall may look like.

• A listing of computer firewall programs as well as additional information about preventing unauthorized access to your computer can be found on document CH000464.
• See document CH000907 for additional information about disabling firewalls.
• Additional information about computer security can be found on our security question and answer page.

Also see: Application gateway, Network definitions, Security definitions, SPI