What is "firewall"

One firewall (in Portuguese: Wall of Fire) is a device of a computer network that aims to apply a security policy to a certain point of the network.

The firewall can be packet filters type, proxy application, etc. Firewalls are usually associated with TCP/IP networks.

This security device exists in the form of software and hardware, the combination of both is technically called "appliance". The complexity of installation depends on the size of the network, the security policy, the number of rules that control the information input and output flow, and the desired degree of security.