Software Firewall

You may have heard the term firewall. If you have a network of computers (say 50 computers in the network) you will implement a firewall to protect your network from the cyber attacks. A firewall controls the ports that are used to communicate with the network. You can implement your own laws concerning the security of the network. You can allow the FTP to restricted number of computers. You can also regulate the computer from visiting certain restricted sites. If the network is large the security must be as tight. But what about the case of one or two computers connected to the internet ? The software firewall is the solution. Te software firewall examines the ports connected to the internet and regulates it. It also asks the user whenever an applicayion installed in the computer try to access the internet. Thus we can prevent unwanted usage of the internet by the unknown application. This also saves our band width. The usage of internet connection by the unknown application is generally a trojan or spyware.
The usage of the software firewall is not limited to the small network. It is also used in the huge network to regulate the usage of the internet by the employees.

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The firewall uses the following ways to prevent the unwanted data transfer through the internet.

• Proxy Service: The information received from the internet is received and it is forwarded to the requesting system. It can also receive the information (request) sent by a computer in the network and forward it to the corresponding destination.
• Packet Filtereing: The information to be sent are breakdown into small units and are converted to packets. These packets are first received by the firewall and checks it with a set of predefined filters. The firewall allows only the trusted packets to pass to the requesting computer.
• Stateful Inspection: It is a newer method. It does not checks the whole packet. Instaed it checks for only certain parts of the packet. It checks specific part of the data while sending the request and compares it with the incomming packets. If a match is found the packet is considered as a trusted packet and allowed to pass through the network otherwise it is blocked.
  

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