IPv4 Subnetting Tutorial for Beginners: How to Calculate Subnetting in IPv4

Do you want to learn about IPv4 subnetting and what it means for Internet users? Then this article has been written specifically for you as it will be used to discuss IPv4 subnetting.

Subnetting in IPv4

If you are a network admin or you want to create your own proxy server, there is a high chance that you will at some point carry out IP subnetting in other to have your network divided into manageable units in other to simplify your workflow and reduce traffic congestion. IP subnetting is not only peculiar to proxies and office networks.

Any computer network that follows the Internet protocol such as your LAN and WAN, including the Internet at large, all benefits from IP subnetting. Usually, when buying many IP addresses, what you get is an IP subnet that will contain a defined number of IP addresses depending on its mask. It is important you learn about IP subnetting in other to know how to effectively use them to your advantage.

In this article, our focus is on IPv4 subnetting. You will learn what IPv4 IP addresses are, IPv4 subnetting, and how to calculate subnetting in IPv4. Also important to learn is how web services make use of IP subnets for preventing spam – and how to evade such.


What is IPv4 Subnetting?

IPv4 Subnetting

IPv4 subnetting is the process of dividing IPv4 IP networks into blocks or subnetworks so that each subnetwork (subnet) will have IP addresses that are identically in the same bit group. Each of these is known as an IPv4 subnet.

An IPv4 subnet is a logical subdivision of an IP network. IP addresses that belong to the same subnet are addressed with an identical most-significant bit-group. This leads to the logical division of an IP address into a network number and host identifier. The number of IP addresses in a subnet when subnetting is carried out depends largely on the subnet masks, which many see as the type of the subnets.


Why Carry out IPv4 Subnetting?

There are a good number of reasons why you will want to carry out IPv4 IP subnetting. If you already have your own use case, you can either briefly check this section or move to the next section for the real deal. However, if you do not have a use case in mind, then the below are some of the reasons why you will have to carry out IP subnetting.

  • Division into Smaller Units for Management Purposes

Division into Smaller Units for Management PurposesOne of the most important uses of subnetting is to help break large IP networks into smaller units which makes it easy for management. If the system is faulty, you can quietly troubleshoot as you go down to the subnet with the issue and find out what the problem is. This is different from having a large network that will waste your time and make management slow and ineffective.


  • Reduce Wastage of IP Addresses

Reduce Wastage of IP AddressesIf you have tried using a Class C network that contains 256 IP addresses, you will know that not all of the IP addresses are available for your usage. Breaking up large networks into smaller pieces will help conserve a great amount of IP addresses, especially if you have a good number of hosts to deal with.


  • Reduce Network Traffic

Reduce Network Traffic

Another use case of IP subnetting is to deal with network congestion and reduce network traffic. This is because creating subnets will lead to smaller networks that form smaller broadcast domains which eventually leads to less broadcast traffic on the network boundaries. This will help reduce traffic congestion and improve performance.


How to Calculate Subnetting in IPv4

When a network becomes too large, congested, and difficult to manage, which could also lead to a drop in performance, the best way to solve this problem is by diving the network into manageable subnets which from the above, you know the process of getting that done is IP subnetting.

Sometimes, dividing a network either because it has become too congested or you just got it delivered, and you want it divided into manageable units is not easy. Performing this calculation can be difficult, especially when you have many parameters you are dealing with. For this reason, you are better off making use of a subnet calculator. Below is the step you will take to make use of a subnetting calculator.

MX Toolbox subnet calculator

  • Use your browser to visit the tool webpage by clicking on the URL above. You will see an input box, an optional pull-down option for specifying the mask, and a calculate button.
  • Let say you have a subnet range (CIDR) of 74.125.227.0/25. You will enter 74.125.227.0 in the input field and then select /25 from the option provided. You can as well just enter 74.125.227.0/25 and disregard the option.
  • Click on the calculate button. This will carry out the subnetting automatically for you.

subnetting calculate

  • Information provided after the process includes the subnet range you entered, the CIDR IP range, input long, CIDR long-range, input hex, CIDR hex, IPs in range, Mask bits, subnet mask, and hex subnet mask.
Conclusion

Looking at the above, you can see that it is actually easy to calculate subnets in IPv4, thanks to the programmed subnetting calculators out there. Without using a subnetting calculator, the process is complicated and error-prone – it is also boring.