A network firewall is a device that acts as a barrier to keep destructive forces away from computers on a network behind the firewall. A network firewall is similar to a physical firewall that keeps a fire from spreading from one area to the next.

Firewalls can prevent the following security threats:

• Remote login by unauthorized users (such as hackers).
• Backdoors, which are programs that establish features that allow for hidden access.
• Denial of service, where a network is inundated with generated network traffic, causing computers on the network to slow down or crash.
• Network-spread viruses and worms, which are small programs that can spread over the network to other unprotected computers.

Firewalls, however, cannot prevent the following security threats:

• Viruses, worms and Trojan horses from e-mails and downloaded files
• Spam
• Spyware

Other security controls may be needed to complement the protection a network firewall provides. While firewalls can stop network-spreading viruses, anti-virus software should still be installed on computers.

All University departments and units are required to use Enterprise Network Firewalls. These firewalls, operated by CSSD, help protect sensitive information, research data, and support critical University Operations. Individuals are encouraged to enable the Microsoft Windows Personal Firewall on their PCs.

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