These are computers that monitor incoming and outgoing traffic. Any potential intruder would be spotted and the authorities notified. As such, it is the first level of security in a network. As the name implies, a firewall is a built-in form of protection designed to limit potential damage. Firewalls most often take the form of software but may also consist of hardware or a combination of both.
Passwords are a common software solution to preventing unwanted access.
Each time you provide a password for Internet access, you cross the firewall set up by your Internet service provider. The subsequent firewall allows people within the organization to view content hosted on the external Web site, while preventing public access to the internal site, also known as an intranet. Firewall technology keeps evolving to maintain pace with determined hackers, who attempt to break into computer networks. Most online merchants post their privacy statements on their Web sites. Click here to see Visa's privacy statement.