Do you know the use of firewall ?

A firewall is a kind of blockade for your computer.It stops unauthorised data from getting either in or out of your machine.

                                       

A firewall can take a form of either hardware or software.for years large corporation have used them but even home users are also recognising their needs. They work by means of three techniques.First,packets of data may be analysed against a set of filters,and unsafe information is flagged and not allowed through;a proxy service retrieves the information from internet which is then retrieved by a firewall and sent through the destination server or by stateful inspection ,which can analyse the data looking for key characteristics that identify it as being unsafe