What is firewall and how it work?and types of it.In details

What is firewall and how it work

Hello friends, today we will know what is firewall and how it works. In the world of computers and Internet, you must have heard the name of firewall, what it is and what is needed in the computer. You will know all the information related to this article, so be sure to read it till the end.What is firewall and how it work.

If you are a computer student or interested in computers, then many questions related to your firewall must have come and if you are worried about cyber security then this post is even more useful for you. So without wasting much of your time, let’s start with why a firewall is important for networking devices .What is firewall and how it work

What is firewall

“A firewall in any computer is for the network security of the computer which prevents the unwanted traffic coming through the Internet in the computer”. When our computer is connected to the Internet, many types of data keep coming in it and sometimes some malware or computer script comes with these data which can harm the computer.

The task of firewalls is to stop these files or data so that your computer is protected from hackers. Firewall acts like a wall between your computer and the Internet and from the Internet, only the data that you have access to your computer can come.

Apart from this, if any unauthorised data tries to reach the computer, the firewall will stop it before reaching the computer. Any data that does not have the IP address of our network, the firewall disallow it.What is firewall and how it work

How does a firewall work?

As the firewall is used to filter the traffic coming into the computer. For this, there are some special software in which this program remains, which data has to be allowed to enter and which has to be stopped. Whenever we send a request from our computer to the Internet, our network ID is included in that data and whenever any data comes from the Internet to our computer, then it also has the ID of our network.

If any such information comes from the Internet to our computer, in which the ID of our network is not available, then the firewall blocks this information before it reaches the computer. Apart from this, there are many advanced firewalls that follow many factors besides network IDs. Next, in this article Firewall, we will know how many types are there.What is firewall and how it work

Types of Firewall

However, there are two types of firewalls – Hardware and Software or both of them are also mixed. You can take Modem to understand the hardware firewall, from which the entire Internet traffic is filtered and goes to the computer. There are many types of firewalls. Let’s understand it briefly –

Packet Filtering Firewall
Circuit – Level Gateway Firewall
Stateful Inspection Firewall
Application Firewall
Next Generation Firewall ( NGFW )

Packet Filtering Firewall

This type of firewall was first created and computers use it the most. Packet Filtering Firewall monitors and controls all packets of data from the Internet to the computer. Meaning it can also monitor packets of data and allow them to be intercepted or let go.

Packet Filtering Firewall works on top of some Predefined Set of rules . In this, it is already programmed which type of data packet to block and which to allow. Such as Device IP Address, Port Number, Protocol header, etc. If the data packets are set according to the criteria set in the firewall, the data is given access to go to the computer otherwise it is blocked.


Circuit – Level Gateway Firewall

This type of firewall uses a Proxy Server . This firewall works on TCP and OSI model.In this, a firewall is placed between Source and Client which in a way acts like a Proxy Server. In this, when a user accesses a web page , he does not have access to the real IP address of that serverbut rather reaches the IP of that gateway firewall.

Let us understand this with an example that the IP address of Source is and the IP address of Circuit – Level Gateway Firewall is and when any data packets are emitted from Source then Gateway Firewall will send this packet to its own IP Replace it so that the destination does not know what the original source of the packet is.

“Circuit – Level Gateway is also called Proxy Firewall because it uses a proxy server.”

Stateful Inspection Firewall

It uses both Packet Filtering and Circuit – Level Gateway firewalls. Such firewalls have both Packet and Session filtering. The Secure Connection is checked and the data packet is filtered and if there is an issue in either of these two firewalls then the Connection is canceled.

Application Level Firewall

This type of firewall is used at the application level. It is used to protect a specific application or web services. Its purpose is to protect an application from various Vulnerabilities. Especially, it is more used to protect Web Services .

Nowadays, as hacking is increasing on the Internet, security is also getting boosted so that Hacking activity can be stopped. There are many hackers who are trying to hack various applications and websites. Application Level Firewall is used to prevent all these things.

Application Firewall can be remotely controlled. If a new virus or malware comes, then this type of firewall is also updated. For example, if a person of specific IP address is trying to hack a site, then a person with this IP can be blocked from access to that site, so that the application or website will not be able to visit that IP address.

Next Generation Firewall ( NGFW)

This is the advanced category of firewall which includes the traditional ie present-day firewall like packet filtering, proxy support etc. Apart from all this, Advance Techniques are included in Next Generation Firewall like Deep Packet Inspection (DPI), Intrusion Prevention System (IPS), Packet Analyzer etc.

The next generation firewall will be very helpful for the security of the computer because the existing firewall is not strong enough to fully analyze data packets . But NGFW i.e. Itinclude some more technology which can make the firewall much better. These techniques are given below –

Encrypted Traffic Inspection

Website Filtering
Content Filtering
Antivirus Protection
Include Strong OSI Model

Some specific information about Windows Firewall

Windows Firewall is a Firewall System from Microsoft windows known as Windows Defender Firewall. It was first implemented in 2003 in Windows XP Operating System and Windows Server. And at that time it was called Internet Connection Firewall.

Windows Firewall also blocks the Harmful Program coming through the Internet to your system . This creates a secure connection between your system and the Internet. If your computer system has Windows Defender On, then it also prevents Malicious Software from being installed in your computer . Also tries to keep your system Virus Free.


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Why and who built the firewall?

After the invention of the World Wide Web , communication through the web was growing rapidly. Which included from General Information to Payment Services. Due to this, it was necessary to secure the data on the Internet and various security systems were being made about it.

Created in 1989 to create Secure Connection between Computer and User which was of packet filter type. Firewall was first invented a filter system known as the Packet Filter System in 1987 by Engineers of Digital Equipment Corporation (DEC) . That’s why Inventor Of Firewall can be called Engineers of the same.

After this, Bill Cheswick and Steve Bellovin of AT&T Bell Labs continued their Research Packet Filter and started work on First Generation Architecture in their company.

Is a firewall necessary in a computer (Use Of Firewall)

Till now we have understood that the work of firewalls is to prevent such information coming from the Internet in the computer which can harm the computer. The way we get a gate outside our house or school so that no one can enter the house or school without permission.

Similarly, every computer should also have a firewall so that no non-essential data can reach the computer.
Now many types of Advance Firewall are being made which can analyze the packet of data coming to the system in a complete manner and disallow it if any type of problem arises.


Friends, I hope you have liked this article What is Firewall . However, if there is any question or suggestion related to this article, then let us know by commenting. Many issues related to firewalls have been discussed in this post. As such, its type and usage and its history have also been told.What is firewall and how it work.


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