Firewall

A firewall is a type of software program that prevents unauthorized access to or from a private network.

The core role of firewalls is to isolate a computer from the internet and carefully inspectes each packet of data as it arrives (inbound or outbound) to determine if is should be allowed to pass. Firewalls as a vital part of IT security to ensure networks and data remain safe from unwanted violations. 

Common firewall providers include Cisco, Checkpoint and McAfee.