Everyday millions of people around the world use the Internet for corporate use, research, and personal uses. If each person uses one computer to access the Net at any one time, that is trillions of bytes of data. People are in danger of being "infected or "hacked easily by brilliant hackers. What can a person do? The solution is to protect your computer using firewalls. Basically, a firewall is a barrier to keep destructive forces away from your computer.
A firewall is simply a program or hardware device that filters the information coming through the Internet connection. If incoming information is unusual by the filters, it is not allowed through.
Firewalls use one or more methods to control traffic flowing in and out of the network:
- Packet Filtering: Packets (small bits of data) are analyzed through a set of filters and then let through into the computer or to be discarded later
- Proxy Service “ Information sent from the Internet is retrieved by the firewall and then sent to the requesting system and vice versa
- Stateful Inspection “ The firewall examines certain key parts of information that is suitable to allow into the computer.
There are two levels of network policy that directly influence the design, installation and use of a firewall system. The higher-level policy is an issue-specific, network access policy that defines those services that will be allowed or denied from the restricted network. The other network policy is the lower-level policy describes how the firewall will actually go about restricting access and filtering the services that were defined in the higher-level policy. Firewalls often implement service access policies that allow some user access from the Internet to selected internal hosts, but this access would be granted only if necessary and only if it could be combined with advanced authentication.
The firewall design policy is specific