A network firewall can be defined as a device that checks traffic (for security purposes) between more than two networks.

The network firewall is a fantastic multi-tasker.

(1) A firewall monitors, inspects and controls inbound and outbound network traffic.

(2) It makes use of user-defined preferences to allow or deny communication with a specific network. These preferences point out the criteria and the features by which the firewall decides to allow or discard the network traffic. Packets are checked to examine their purposes. If the content looks suspicious and intends to make illegal attempts, then the firewall will immediately block them.

(3) The firewall also checks the sender’s IP address. More often than not, the firewall deletes the packets without even looking through them. If it is an unknown IP address and the firewall is set accordingly, it will automatically bar the entry of the packets.

(4) Network firewalls are also used to isolate computers belonging to a particular network from other networks. To be even more precise, this firewall can also compartmentalize sub-networks within a huge corporation network. To zoom in even further, the network firewall can also be used to keep a private network separate from the Internet.

Therefore, network firewalls are crucial in isolating your network from others that you want to limit or control communication with. A comparison from daily life may make the explanation simpler. A firewall can be compared to a family dog that only recognizes and allows family members and friends to enter the house, while keeping strangers at bay. Or a firewall can be compared to a body guard. This firewall body guard knows when to allow someone to approach you and when not to allow someone to approach you. However you want to look at it, a firewall is an essential piece of hardware or software, or combination thereof (in whatever form you use)to keep your PC and network safe from intruders.

About the Author:

Lawrence Heller is an author and software development manager. See more of his articles at Firewall Secure and Firewall Advice.