A Firewall is a network security system , it could be software or hardware based , but the ideal firewall configuration will consist of both .
It acts as a barrier controlling the flow of data which is either incoming or outgoing
On a set of rules .
Firewall also controls the access to the resources of a network through a positive control model , this means that the only traffic allowed onto the network must be defined in the firewall policy ; all other traffic is denied .
Hardware firewalls can be purchased as a stand-alone product but are also typically found in broadband routers, and should be considered an important part of your system and network set-up. Most hardware firewalls will have a minimum of four network ports to connect other computers .
Software firewalls are installed on your computer (like any software) and you can customize it; allowing you some control over its function and protection features. A software firewall will protect your computer from outside attempts to control or gain access your computer .
Firewall was first established when organizations began moving from "Mainframe Computers" to "Client-Server model" .
The ability to control access to the server became a priority , before firewalls showed up in the late 1980s , the only real form of network security was performed by "Access Control List (ACLs)" residing on routers .
"ACLs" determined which IP addresses were granted or denied access to the network.
Firewalls are used to protect both home and corporate networks. A typical firewall program or hardware device filters all information coming through the Internet to your network or computer system. There are several types of firewall techniques that will prevent potentially harmful information from getting through :
First generation : Packet Filters :
It was first invented in 1988 , when engineers from Digital Equipment