A firewall is a system that blocks unauthorized access to or from a private network. Firewalls can be hardware, software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All computers connected to the Internet must have a firewall, either as part of the network device or as an installed security program.

A firewall is a system that blocks unauthorized access to or from a private network. Firewalls can be hardware, software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet …