So what’s an IP Address?

Well if we think about the OSI Model and we remember how switches talk to each-other using mac-addresses. We could say that IP addresses is the same equivalent and allows computers to communicate across the network. I want you to consider an IP Address as the address where each computer lives. Imagine every computer, switch, firewall or router on the network was a house on a street, and the street address for each house would be an IP address. This means we all have a unique address and if someone wants to send us a package only the right house would receive it instead of everyone in the street.

So in short, an IP address is a unique address that we can assign to a computer or network device for network connectivity.

IPv4 addresses

Now that you understand the need of an IP address let’s talk about the two different IP address types you will see while in the networking landscape. We are currently making use of IPv4 in this day and age, it is the 32bit address which we have assigned to just about everything. This is typically our 192.168.x.x or 10.x.x.x addresses that you see on a daily basis.

These addresses can also be classful or classless where they follow a certain subnetting scheme, we will touch more on subnetting in the next post. The bad news for us and IPv4 is that it has become nearly exhausted, to give you a good idea there’s nearly 4,3 Billion IP addresses available. New devices are created every day that also require internet connectivity supporting our human population of over 7.6 Billion people.

Not everyone has access to a device or to the internet, although you can already see the problem if there’s nearly double the amount of people as there are IP addresses. Not only that but many of the IP address spaces in IPv4 have been cut out for certain purposes, which means they cannot be used at all for our own addressing.

This causes a potential problem, as what happens when there are no more IP addresses that we can assign? Well… there has been things like NAT (Network Address Translation) that has been keeping IPv4 alive as we are able to hide multiple IP addresses behind a single IP, but this only gives us a short-term solution and it is because of this that some very smart people have been working on the next-generation of IP addressing namely IPv6.

IPv6 the savior

Since we’ve determined that IPv4 is a limited resource and we will eventually run out of addresses the process to replace IPv4 started as long ago as 1998. Where IPv4 is a decimal value with 32bits an IPv6 address consists of 128bits and uses hexadecimal. This makes the amount of IP addresses that can be provided by IPv6 nearly innumerable. I once heard a joke that if our race was able to colonise every planet in the galaxy and had the same population as on earth that we would have addresses to spare. That is a staggering size of address space and definitely eliminates the problem of address exhaustion. We would also be able to scrap certain network requirements such as NATs as every machine would be able to route to the internet directly with its own unique address.

So why haven’t we all switched over yet? Well… there are places already making use of IPv6, although a lot of the world is still stuck on its IPv4 ways. Some parts of the world also do not have the technology to replace IPv4 and it could potentially cause some issues if we just tried to bring IPv6 into the mixture. My personal thought on the matter is that we are just creatures of habit and we are just scared to embrace new technology when it is coming. I just want you to remember that IPv6 is coming, even if we cover a lot of the future posts in IPv4 as it is current, do not forget that IPv6 is around the corner and is something that you will need to know about.

Private IP addresses

Since I mentioned that we make use of NAT (Network Address Translation) to hide IP addresses behind another. I think we need to discuss the two biggest types of IP addresses you will see name Private and Public IP addresses. A private IP address is something that is not routeable on the internet. These are addresses that we assign within our own private networks. There’s specific address spaces cut out of IPv4 just for us to use however we want in our local networks, please see below.

IPv4: – – –

fd00::/8 (You can put in any hex value between the two colons)

Public IP addresses

Public IP addresses are routable on the internet and it is through public IP addresses that we communicate with each-other on the internet. The addresses used by us are given to us by Internet Service Providers which they in turn receive from IP address organisations called Regional Internet Registries or RIRs for short, click here for more info on RIRs

These are generally the IP addresses in-between the private IP ranges that are used for routing on the internet, to see a public IP address simply go into your command prompt or terminal window and ping

The address you see replying is a public IP address.


You have learned what an IP address is as well as the difference between an IPv4 and IPv6 address, as always I hope this has been informative and I would like to thank you for taking the time to read this. I will also suggest that you subscribe to our mailing list in order to get updates of any new content that is posted.

Hungry for more?

Why not read up about Subnetting in our next post or review Firewalls in the previous article?

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The Network Berg

Network solutions specialist with over 12 years of experience in the computer networking landscape. Involved with solution design, project planning and implementations on Enterprise and ISP networks.