The Interactive Glossary: Defining the Net
Firewall
A firewall is a software buffer placed between a computer and the Internet. A firewall allows only "safe" data from the Internet to flow in. This protects you from intruders or hackers who might try to break into your system via the Internet.
These days, most operating systems have built-in firewalls. Make sure the firewall is enabled before connecting to the Internet.
Learn more: Security Tips
