Understanding Firewalls

A firewall is a program that protects your resources by filtering network packets. Firewalls can be run as part of another piece of software. For example, your Wi-Fi access point/router almost certainly provides some kind of firewall capabilities. Firewalls can also be run as individual programs on computers. Finally, sophisticated firewalls can be run on servers dedicated to that purpose, although this generally only happens in enterprise-class setups.

Firewalls enable a network administrator to determine which clients inside a network can access network resources and which ports can be used from outside the network to access the network. In case you are wondering, a network port is a logical endpoint on the network. ...

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