A Firewall is an element of a company's Information Technology infrastructure.

A Firewall determines the boundary of the "Trusted" components of the company's Information Technology infrastructure.

A Firewall protects sensitive data against accidental or malicious damage.

A Firewall protects the computer suite against physical attack.

A Firewall protects against unauthorised network access.

A Firewall protects against viruses.

A Firewall can screen every message coming into or out of the company network looking for key words, or attachments.