It is sadly quite rare that computer users realise that there are irresponsible pranksters out there, who use automated robots to scan IP addresses and target them at the first given opportunity.

Home network faces similar threats like those faced by corporate networks; still, the practice of using a firewall at home has not yet turned popular. However, business organisations widely utilise it, for they are acutely aware of the need for protection.

A Firewall

80% of data theft is an insider’s job and it occurs after the traditional business hours. In such a scenario, protection of data assumes great importance (given its priceless nature). We require a system that can not only prevent unauthorised access to our computers but also restrict the flow of data over the network.

Such a system is the firewall. It is a secure machine that is configured with a given set of rules to monitor the network traffic and is placed between a private and public network forming a boundary between these two. It limits the network traffic in compliance with the local security policy. In other words, it works as an electronic gate and allows the passage of only some information while blocking the rest. Some organisations even have firewall protection segregating corporate information.

The Different Types of Firewalls

Firewalls can be constructed in different ways. Larger corporations set up two machines that act as filters allowing only certain type of information transmission over the network. In between these two chokes resides the World Wide Web proxy server. This is a safe arrangement for it enables a greater control.

However, one machine is adequate enough to serve all functions and it is easier to manage too, besides being inexpensive. Smaller organisations adopt it for the inherent advantages, but it is less secure for any weakness in it can be exploited to access the information over the entire network.

A better mode of protection would be using the hardware and software firewall simultaneously. Large amounts of network traffic necessitate a hardware firewall and a software firewall is required to inspect the content of the internet traffic for it contains complicated filters. Used in combination, these offer the required protection from those who attempt to illegally access data.

The Firewall Mode of Protection

Data transfer over the internet occurs in packets from the source machine to the destination. To enable a packet of data to reach the right destination, it contains the receiver’s address and port number. Similarly, the data packet also contains the sending machine’s IP number and port number. The firewall inspects these information packets and decides whether to accept or decline it based on the sending machine’s IP address and port number and the destination machine’s IP address and port number. Once the receiver receives the data it sends an acknowledgement. Those that are not accepted simply disappear from the internet.

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