Types of Firewalls and Network Security

Today we are going to understand different types of firewalls and decide which firewall will be best or will best suit you as per your implementation and your environment.

So let’s start –

Firewalls protect our computers from internet hackers. Internet hackers can steal our bank details from our computers and reduce our bank balance from thousands of dollars to zero dollars within seconds. So firewall is must in a computer or in a computer network.

There are 3 types of firewalls:

1. Packet filtering firewalls
2. Application/proxy firewall
3. Hybrid Firewall

Before starting with firewall types you should know what are data packets?

When we want to download a file or site say if its 200MB from the internet then we will not receive the entire 200MB data at once. But we will receive small packets say 5MB every second. Some of the parts of this 5MB packets are occupied with an information like which computer is sending the data, which computer is receiving the data etc. The remaining portion of this 5MB packet contains the part of the actual data that we want to download.
So the part of the active data plus some information together forms a data packet or IP packet and this part of the actual data is called payload. Now we can start with firewall types.

1. Packet Filtering Firewalls:-

Starting with packet filtering firewall suppose we are downloading a file from the internet when the data packet arrives at a packet filtering firewall, it only checks the senders and the receivers IP address and the port number present in the data packet.
The rules written in a list is called Access Control List. They are used for data packet verification. If everything is OK then the data packet is allowed to pass through the packet filtering firewall and then to our computer.

But what is Port Number? Actually, these are some digits written after IP address separated with a colon and are used for the successful data packet transfer.

The packet filtering firewall is already present in the computers so they are the cheapest and the quickest way to implement. The only limitation of packet filtering firewall is that it does not check the database portion i.e. Payload of the data packet.

So a hacker could send some malicious data packed in this Payload of the data packet. Hence packet filtering firewalls provide low security.

2. The second one is the Application/Proxy firewall:-

Let’s understand with an example. Suppose your mother asked you to buy a pen from the market. You go to the shop, buy the pen, comes back and give the pen to your mother.
Here you have done the work that your mother wants you to do. Without letting the shopkeeper knew who actually wanted that pen?

Same is the case with application/proxy firewall. Replace the shopkeeper with the internet, your mother with a personal computer and yourself with a proxy firewall like you did not let the shopkeeper knew that your mother was the one who actually wanted that pen.

Similarly, proxy firewalls do not let the internet know which computer actually wants to visit the request to the website i.e. proxy firewalls hides us from attackers on the internet.

Let’s understand the whole process:-
The user enters the website www.Hostripples.in in the web browser. The proxy firewall reads the request and forwards that request to the internet. The web server on the internet receives the request and responds back to the proxy firewall with the requested information.

The proxy firewall receives the information and forwards it to the original client giving the login page for who has given this web address. In this whole process web server thinks that proxy firewall is one who wants to visit www.hostripples.in i.e. proxy firewalls could not let the web server know the original requester. So proxy firewalls protect us from the potential attackers on the internet by not disclosing our computers identity or we could say not disclosing our computers IP address. Since application firewalls also check the payload of the received data packets. So they are generally much slower than the packet filtering firewall.

3. The third is Hybrid Firewalls:-

Hybrid firewalls combine packet filtering firewalls and application firewalls in series to enhance the security. If they are connected in parallels then the security of the web connection will be reduced to the parameters defined by packet filtering firewalls i.e. application firewalls will be of no use if the two firewalls are connected in parallel. For this reason, hybrid firewalls use packet filtering and application firewalls in series.

As a result hybrid firewalls will be best for us – will depends on its implementation environments for ex- Packet filtering firewalls will be best in low-risk environments like low-risk jobs, application firewalls will be best for the medium risk environments like universities and Hybrid firewalls will be for high-risk environments like Hospitals whose database contains important reports of the patients.

Now you can choose your firewall as per your need. If you find this article helpful then please leave a comment.

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