A firewall is basically something that protects the network from the Internet. It is derived from the concept of firewalls used in vehicles which is a barrier made of fire resistant material protecting the vehicle in case of fire. Anyway a firewall is best described as a software or hardware or both Hardware and Software packet filter that allows only selected packets to pass through from the Internet to your private internal network. A firewall is a system or a group of systems which guard a trusted network( The Internal Private Network from the untrusted network (the Internet.) To understand how a firewall works, firstly we need to understand how exactly data is transferred on the Internet. The TCP\IP suite is responsible for successful transfer of data across a network both the Internet and the Intranet. The TCP\IP suite is a collection of protocols which are inter-related and interdependent and act as a set of rules according to which data is transferred acro...
The best we test are the best you get..!