Firewall is nothing but a dedicated software or a hardware or sometimes the combination of both, which inspects network traffic passing through it and denies or permits passage based on a set of rules.

here the user defines the rule, based on which it follows.

A firewall is a device or devices that control traffic between different areas of the system network.

The system typically see two or three firewall devices, as well as many other security components to protect organisation’s resources.

Firewall capabilities:

as it defines a single choke point that keeps unauthorised users out the protected network.

It is a convinient platform for several internet functions that are not security related.

A firewall can serve as the platform for IPSec. Using the tunnel mode capability, the firewall can be used to implement virtual private network.

Firewall limitations:

The foirewall cannot protect against the attacks that bypass the firewall.

The firewall doesnot protect against internal threats.

The firewall can not protect against the transfer of virus infected programs or files.

The following are the methods of control in firewall.

1. user control

2.access control

3.behavior control

4.direction control


heregoes the types of firewalls

1.Packet filtering

2.Application gateways/proxies

3.Circuit level gateway


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