An Internet firewall is a device or software that is designed to protect your computer from data and viruses that you do not want. A firewall is so called because of the real firewalls used to secure buildings. A physical firewall is a set of doors that closes in a building so as to contain a fire to one area, preventing the entire building from being destroyed. Likewise an Internet firewall is designed to shut off access to your operating system or to other computers that are connected to your network.
Firewalls can be implemented in two forms:
1. Software Firewall
A software firewall is a special type of computer software running on a computer. It protects your computer from outside attempts to control or gain access, and, depending on your choice of software firewall, it could also provide protection against the most common Trojan programs or e-mail worms.
2. Hardware Firewall
It is physical piece of equipment designed to perform firewall duties. A hardware firewall may actually be another computer or a dedicated piece of equipment which serve as a firewall. Hardware firewalls can be effective with little or no configuration, and they can protect every machine on a local network.
Firewalls keep out malevolent hackers and people who intended to do damage and take over other peoples' servers. Firewalls really serve no other purpose. Firewalls seek to limit the access to a server or computer and let in only the people who need to be there.
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