What is a firewall? Why do I need one for my computer?

This article explains what a firewall is and why it is important for protecting your computer or network from malicious threats. It also provides guidance on enabling built-in firewalls on Windows and macOS and directs users to the C&IT Help Desk for additional support.

A firewall is a protective barrier that prevents unwanted sources such as viruses, worms, trojans and other malicious code from accessing your computer or network. Firewalls can be either hardware-based or software-based. These two types of solutions can also be used in conjunction with one another.

C&IT highly recommends that you use a firewall. Newer operating systems (such as Windows 8.1, 10) and Mac OS X 10.4 and above) have software-based firewalls built-in. To configure these built-in firewalls, click the provided links below.

Windows 11

• Turn Microsoft Defender on or off.
  

Apple

• macOS: Use a firewall to prevent unwanted connections on Mac

If you have difficulties turning on your firewall or have a system not listed above, please contact the C&IT Help Desk.