How Do IP Addresses Work?

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Hello Readers! In this blog we are going to see how our IP addresses work. Therefore, for understanding its working we will see first what is an ip address and after that we will understand its working. So, let’s start!

What is an IP Address?

An IP Address stands for Internet Protocol Address. If we want to send a letter to anyone we need their mailing address similarly the computer uses the IP address of the device to communicate to another computer within the network. So, basically an IP address uniquely identifies a device on a network.

An IP address comprises four hexadecimal numbers of 8 bits field separated by symbol dot “.” Each number varies from one to three digits and these four numbers range from 0 to 255 bits.You’ve seen these addresses before; they look something like this:

The Two Parts of An IP Address

Any device IP address consists of two parts:

Network ID: It consists of 8 bits of the total address. For instance: if I have an IP address, the 194.168.3 part of the address will be the network ID. It means that the network ID is a part of the IP address starting from the left that identifies the specific network on which the device is located. 

Host ID: The rest which is left is taken up by the host ID. Similarly In the above instance host id will be 34. It uniquely identifies a device in the network that we can assign to each host.

On your home network, then, you might see several devices with IP addresses like,, 192.168.1 30, and All of these are unique devices (with host IDs 1, 2, 30, and 34 in this case) on the same network (with the network ID

Uses and Classes of IP Addresses

  • Class A: The IP Address in this class ranges from 0 – 126 with a subnet mask of It supports approx.16 million hosts on each of 127 networks. Mostly used by Internet Service Providers (ISP)
  • Class B: The IP Address in Class B ranges from 128 – 191 with a subnet mask of supports approx. 65,000 hosts over each of 16,000 networks. Used by medium and large-sized networks in enterprises and organizations.
  • Class C: IP Address ranges from 192 – 223  with a subnet mask of It has 254 hosts on each of the 2 million networks. This class address is most common and used in small business and home networks
  • Class D: IP Address ranges from 224 -239 with no subnet mask. It is reserve for multicast groups.
  • Class E: IP Address ranges from 240 -255 with no subnet mask. It is reserve for future use, or research and development purposes.

The Subnet Mask

So, how does your device determine which part of the IP address is the network ID and which part the host ID? For that, they use a second number that you’ll always see in association with an IP address. That number is called the Subnet mask.

Uses of IP Address

  • To assign Static/Dynamic IP addresses to new devices in a network in order to have communication.
  • Different protocols like DNS, DHCP, etc work on the concept of IP Address.
  • Proper tracking, security and monitoring of millions of devices in the network.
  • Source routing features which allow the sender of a packet to specify which route the packet should take on the way to its destination.

How Are IP Addresses Assigned?

However all of these addresses are allocated by the Internet Assigned Numbers Authority. This nonprofit U.S. corporation coordinates global IP addresses, which you can read all about here.

More specifically, IANA assigns blocks of IP addresses to regional internet registries. In turn, these regional registries allocate addresses to ISP, companies, schools, and similar institutions within their zone.

Similarly IP address probably comes from your company network or ISP, which received that address from a regional internet registry, which was allocated a block of addresses from IANA. (It’s a process.)

IP Addresses Based Network:

Let’s see how do IP Addresses Work, based on two types of network:

  • Public: A public IP address is an address assigned to a computing device to allow direct access over the Internet. An email server, email server and any server device directly accessible from the Internet are public IP addresses which are globally unique and can only be assigned to a unique device.
  • Private: Private IP address is assigned to computers within your private space without letting them directly exposed to the Internet. For instance, if we have multiple computers, mobile devices within your home you may want to use private IP addresses to address each computer within your home. Private IP address starts with :


Therefore In this blog we have seen how ip addresses work. We have seen that IP Address is used for communication between two or more different devices within/outside the network using TCP/IP protocol to locate and administrate devices using Internet Service Provider(ISP). Thanks for being with me till the end. If you find this blog helpful do share with your friends.


Written by 

Naincy Kumari is a DevOps Consultant at Knoldus Inc. She is always ready to learn new technologies and tools. She loves painting and dancing.