What is an IP address?
Today’s topic is the IP address. IP stands for internet protocol, and you can think of an IP address as your computer’s official address. It is how your computer, or any device you use to access to the internet, is able to request, send, and receive data. The internet’s “post office” uses IP addresses to know where to route data so that the correct device sends the information requested by another device, and that the respective device receives the information it requested. In addition to routing data, IP addresses also serve as host and network identification (more to come on this and the importance of security and IP addresses in the next blog post!). To put it simply, an IP address ensures that you are routed to Bed, Bath & Beyond’s website so you can use that 20% off coupon before it expires, instead of routing you to that freaky website your brother visits.
First, I want to explain that there are two types of IP addresses, the original, which is called IPv4, or internet protocol version four, and the newbie in town, IPv6, internet protocol version six. Any device connected to the internet requires its own IP address so that it is uniquely identifiable and can distinctly send and receive the data it requests. Therefore, the internet protocol must allow for a large number of unique IP addresses because of all the devices that require internet connections today to function — devices such as computers, mobile phones, laptops, routers, gateways, printers, smart appliances, smart watches, and so on.
Here is where the problem lies with IPv4 addresses — the protocol is limited to four billion (2^32) unique IP addresses due to the way it was constructed. So this brings us to a trope — that computers are just a bunch of zeroes and ones!
To oversimplify and refrain from getting into the arithmetic and computer science behind IP addresses, that idea is somewhat true here — IP addresses are comprised of octets, made up of bytes, made up of binary digits (bits; AKA ones and zeroes) — which are the core communication method of computers. IPv4 addresses are comprised of four octets and four bytes, one byte in each octet. They are written in dotted decimal notation usually looking something like 10.0.2.15 or 192.168.0.12 in a private, home network. The numbers in the IP address have been converted from binary digits to decimal digits. Each binary digit, or bit, in an octet has a binary weight of 128, 64, 32, 16, 8, 4, 2, or 1, which is how IP addresses are assigned the numbers in their address. There are eight bits in each byte, making an IP address a total of 32 bits. Calculate 2^32, and boom! It’s a fixed number, four billion IPv4 addresses, that the internet is working with for eternity.
So now we know that the IPv4 IP address caps out at about four billion IPs, and we also know that there are nearly eight billion people living in the world. With the diversity of devices that exist, including the ever-growing internet of things (IoT) technologies and smart appliances, the number of devices that each require a unique IP address is increasing rapidly. Queue the IPv6 protocol, IPv4’s big sister that is 128 bits long and can produce 2^128 unique IP addresses, or a number that is so large I don’t know how to verbalize it! The number is close to 340 trillion, trillion, trillion, unique IP addresses, which for the foreseeable future seems sufficient. Though the IPv6 IP address was born in 1998, its adoption has been slow and not scaled due to the cost and complexity of deploying it.
The slow adoption of IPv6 is in part due to another solution released by computer scientists –a protocol called Network Address Translation (NAT). NAT summons forth a piece of information that is important here — there are two additional types of IP addresses within the IPv4 address to consider — public IPs and private IPs. Think about your home network and all the devices in it that communicate with the internet and also communicate with each other because together they form a local area network (LAN). If you would like to print something, your computer needs to communicate with the printer in your LAN, and in such a case a private IP address is used. On the other hand, public IP addresses are used to communicate on the internet, also referred to as the wide area network (WAN). A public IP is the address used when accessing the internet for a certain service, such as email, shopping, reservations, etc.
NAT came to the rescue because it assigned one public IPv4 address to an entire LAN. So if your home network is made up of three computers, five laptops, one printer, a PS5, and a smart thermostat, they are all connecting to the internet — requesting, sending and receiving data — with a singular IP address. When all the devices need to talk to each other within the LAN, they use private IP addresses which are unique and use numbers that are not capable of being used to access the WAN.
If all devices on a home network use the same public IP address, how is it possible that you access the Bed, Bath & Beyond website, and not the gamer website your brother visits? How do you receive the data you requested, instead of your brother’s? We will tackle these questions, as well as security in relation to IP addresses, in the next blog post!
