Firewall

=Firewall=

A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and 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.

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firewalls help to secure a computer by preventing a network access from an external unauthorized user. firewalls also control which users and programs are allowed to be connected to and external network such as the internet.

firewalls can allow or block traffic in to the network by the following ways
 * I.P addreses
 * Domain Names
 * Protocols and Ports