Computer FireWall

Today, everyone wants perfect security and privacy for his personal computer so that no one can access to their personal or important data. There are many ways through which you can lose your privacy or security. Viruses or Spywares enter your PC and get access to your personal information. There are many anti-virus programs that defend you from those viruses.

In addition to the anti-virus programs, there is a default program of Windows that prevent outsiders from getting access to your PC. That is called a “Firewall”.

What is a Firewall?

A firewall is a program that controls what information passes from one network to another. You can use a firewall between your PC and the internet to stop outsiders from getting access to your PC via internet.

How Firewall Works?

Each packet on the internet is addressed to a specific port (input for a specific internet service) number. So you can control access by port. Generally, most of the people use only a few ports for Internet Communication: port21 (for FTP, or file transfer), port 25 (for outgoing e-mail), port 110 (for incoming e-mail) and port 80 (for web pages). If your computer is on LAN, it may use port 139 (for file and printing sharing).

A firewall controls which ports are open and refuse to respond to packets addressed to other ports. Some firewalls enable you to specify what types of packets can across the firewall e.g. requests for web pages might be allowed outgoing, but not for incoming. Some firewalls control only the incoming information but, a good firewall program monitors both incoming and outgoing packets and makes sure that outgoing packets come from a program that you know about.

You can run a firewall program on your computer or on a router or hub that stands between your computer and the internet. For example, if your computer connects to the internet through a local area network, the LAN’s hub or router can run a firewall program to provide protection to the whole LAN.