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What is an IP address ?

Published 7 May 2020

What is an IP Address?

IP stands for Internet Protocol it’s a set of predefined rules that govern how packets of data are sent across the internet. For any 2 devices on the internet to communicate they must be able to find each other. If one device needs to find another it needs to know the location of the other device it’s trying to communicate with. The location of every device connected to the internet is represented by its IP address. The IP address of a device is a unique set of numbers used to identify the device. Sending a postal item to a house is a good analogy. If I post a parcel (data packet) from my house (my computer) to a friends house (their computer) I would need their house address (IP address of their device) and street address (Network address). Considering this, just like two houses on the same street can’t have the same house number, neither can two computers on the same network have the same IP address.

If your device doesn’t have an IP address assigned, it cannot effectively communicate over the network.

4 Types of IP addresses:

Private IP addresses are used to communicate within the same network of a system.

Public IP addresses are used to communicate outside of the network, they connect you to the world. They are mostly assigned by ISP’s (Internet service providers).

A static IP address is one that gets manually created and does not change over time. Dynamic IP addresses get assigned by a Dynamic Host Configuration Protocol (DHCP) server and have the ability to be changed. Most internet users get assigned a dynamic IP address by their ISP.

Differece between IPv4 and IPv6

IPv4 is what we all currently use today.

Due to the fact that IPv4 is only a 32 bit number the total number of available IP addresses is limited to 2 32 or around 4 billion.

Example of an IPv4 IP address would look like:

IPv4: 172.16.81.100

The speed at which technology has grown has meant that we have used up all available IPv4 addresses and a solution needed to be found.

A new version was introduced, IPv6. IPv6 has adopted a 128 bit hexadecimal number which can provide 2 128 of unique addresses for users and devices but it not in full use yet.

IPv6 uses eight 16-bit hexadecimal numbers (8 * 16 = 128 bits) separated by a colon to represent a 128-bit IPv6 address. Example of an IPv6 IP address would look like:

IPv6: 4ggr:1925:5656:7:600:t4tt:tc54:98vt

What does an IPv4 address consist of?

IP addresses are represented by a series of 4 sets of numbers separated by periods. IPv4 addresses are made up of 32 bits (1’s and 0’s). These 32 bits are broken up into 4 octets (8 bit number).

Each octet is represented by a combination of either 1’s and 0’s like this:

(4 octets) of a base 2 nunber (binary)

10101100.00010000.01010001.01100100

It’s hard for us as humans to recognize what a base 2 number represents thus we convert it to base 10. Base 10 numbers are also known as the decimal system, which is what we use and are most familiar with.

Each one of the octets above can represent a number from 0 - 255 So the above binary IP can be represented below in the decimal system.

172.16.81.100

I’ll get into explaining how to convert binary to decimal in another article.