The firewall is one of the most important security features in a computer environment. In the classic sense, a firewall is ...

Software installed in a user's computer that offers protection against unwanted intrusion and attacks coming from the Internet. Personal firewalls are available from numerous security vendors, and ...

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.