Learn how a firewall filters out cyber-threats, while still letting you access everything you want to look at online. When you purchase through links on our site, we may earn an affiliate commission.

A firewall that is provided by software. It often refers to a personal firewall in a user's computer, but software firewalls may be installed in servers as well. Contrast with hardware firewall. See ...

The firewall built into Windows starting with Windows XP Service Pack 2. Windows Firewall provides a stateful inspection of packets that accepts only responses to requests originated by the user. This ...