What's a firewall

[richardmarx]

Firewall is a hardware that is used inside a networked environment to create specific security policies in accordance with local security policy.

The basic task of a firewall is to control traffic between different zones of trust, which includes Internet and internal networks. It is widely used by network administrators as it requires considerable understanding of network protocols and computer security.

[mini_0]

Windows XP's Internet Connect Firewall is really only half a firewall. It only checks information coming into your computer. It doesn't check information going out from you computer. Why is this significant? If you have inadvertantly become infected with a virus, trojan, worm, or spyware, that little malicious devil can send out your personal information, use your computer to infect other computers, or even allow hackers to access your computer to do whatever they please.

[samkhan]

Some where i was read that Firewall is a software as well as hardware.

It can be either of one.

And here you are telling that Firewall is a hardware?

Can you pleace clarify wnat is exactly ?