HOW FIREWALL WORK ?

FIREWALL

Firewall is network system that monitors and control the incoming and outgoing network traffic based on
predetermined security rules.A firewall typically establishes a barrier between a trusted,secure internal network and another outside network,such as internet,that is assumed not to be secured or trusted.

A firewall controls access  to resources of a network through a positive control model.

This means that the only traffic allowed onto the network is defined in the firewall policy;all other traffic is denied.

HISTORY AND TYPES OF FIREWALLS

Computer security borrowed the term firewall from firefighting prevention,where a firewall is a barrier established to prevent the spread of fire.

Firewall technology emerged in late 1980 when the internet was a fairly new technology in terms of its global use and connectivity.The predecessors to firewalls for network security were the routers used in 1980.

Clifford Stoll's discovery of German spices tampering with his system.

HOW FIREWALL WORKS ?

Firewall may decide to allow or block network traffic between devices based on the rules that are Pre-configured or set by the firewall administrator . Most personal firewalls operate on set pre-configured rules which are most suitable under normal circumstances,so  that the user need not worry about configuring the firewall.

Personal firewalls are easy to install and use and hence preferred by end-users to secure their personal computers. However,in order to meet customized needs large networks and companies prefer those firewalls that have plenty of option to configure.

Firewalls use one or more of the following methods to controls the incoming and outgoing traffic in network ;

1) packet Filtering ;- In this method ,packets(small chunks of data) are analyzed against a set of filter.packets filtering has a set of rules that come with accept and deny action.

2) Statefull Inspection ;- This is newer methods that's doesn't analyze the content of the packets.Instead,it compares certain key aspects of each packet to a database of trusted source.

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