23-02-2013, 10:22 AM
Introduction to Firewalls
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Overview of Firewalls
As the name implies, a firewall acts to provide secured access between two networks
A firewall may be implemented as a standalone hardware device or in the form of a software on a client computer or a proxy server
The two types of firewall are generally known as the hardware firewall and the software firewall
Mode of Operation
A firewall that stands in between two networks will inspect a packet that is ready to pass between the networks and allow or block the packet based on the rules set for the firewall to operate
General Firewall Features
Port Control
Network Address Translation
Application Monitoring (Program Control)
Packet Filtering
Additional Firewall Features
Data encryption
Hiding presence
Reporting/logging
e-mail virus protection
Pop-up ad blocking
Cookie digestion
Spy ware protection etc.
Viruses and Firewalls
In general, firewalls cannot protect against viruses
An anti-virus software is needed for that purpose
However, many security suites such as those offered by MacAfee and Norton offer the complete protection
Some software firewalls such as Zone Alarm Pro may contain limited virus protection features