What is an IP address?
Have you ever wondered what an IP address is or what 192.168.0.1 refers to? There’s no avoiding math when talking about IP addresses, so it’s slightly longer and more complex than some other Uswitch guides.
But weather the storm, because we believe it will be very useful for you. Aside from the fact that everyone should know a bit more about how this stuff works, it’s handy to be able to spot basic connection issues and understand techs when they use the lingo.
Basically, IP addresses arose because people who played with the early internet needed a way to identify computer systems when they connected together. IP addresses are like a phone number for your computer: if you dial the same number, you always get the same computer.
IP addresses are born, and like a phone number or address, they contain information about your location.
Checking your IP
Checking your IP address is easy to do.
If you are using Windows – Perform a search on your computer for CMD. Once the command box opens, type “ipconfig” and press Enter.
If you are using a Mac – Go to Applications> Utilities> Terminal. Once you are in Terminal, type “ipconfig” and hit enter.
Provided you are home in the UK, your IP address should start with something 192.168. A typical example would be 192.168.0.1.
Bad IP addresses
If your IP address begins with 169, you will not be able to access the Internet. A 169 address is your router or modem alerting you to a problem by giving you the wrong IP address.
If you are at home, the best thing you can do is turn off and unplug your router for 30 seconds, then plug it back in and turn it back on. If you’re connecting wirelessly, try a cable, and if that still doesn’t work, call your provider – there’s a problem between your computer and your router.
However, if you are at work, involve your IT people.
IPv4, 192.168.0.1 and Internet history
IPv4 was the first standard for IP addresses. 192.168.0.1 is a common example of an IPv4 address. The most recognizable IP addresses are between 192.168.0.1 and 192.168.0.255, as these are usually the ones we use at home.
An IP address is a sequence of four blocks of digits. Each of these blocks has a value between 0 and 255, which means that each block has 256 possible values.
So with four blocks allowing up to 256 possible values, IPv4 allowed about four billion unique addresses, which seemed like a huge amount. It was the early 1970s after all; computers were not particularly ubiquitous, and no one could have predicted the growth of the Internet.
Fast forward to today and with six billion people worldwide, millions of businesses and homes with multiple Internet connections, four billion are nowhere near enough IP addresses for everyone. We work around this problem in two ways: dynamic IP addresses and subnets.
Dynamic IP addresses
If everyone had their own IP address, we would be long gone. Thus, Internet service providers assign IP addresses dynamically, which means that they are used in rotation. Not all IP addresses are always used, so basically dynamic IPs just give you the next free IP address instead of always giving you the same one. This means that when an IP address is not used by one person, it can be used by another.
A static IP address is an IP address that never changes. These tend to be business-only, but for a low cost most home broadband service providers can offer you one as well.
A subnet means a subnet or a network within a network. As Start.
It basically splits up connections so that IP addresses can be reused. An example would be a house with five computers: instead of five individual IP addresses for each machine, there is a primary IP address assigned by the ISP. This primary IP address is assigned to the router, which then creates its own small network and gives all devices the IP addresses from there.
The problem is, we are still running out of addresses. Any device that connects to the internet needs an IP address to do so, and even with dynamics and subnets, there aren’t enough of them. Cellphones, consoles, handhelds, televisions, computers, watches, GPS … all of these devices need IP addresses. We need a new standard.
This is where IPv6 comes in.
IPv6 uses a different system which allows for many more combinations. IPv6 uses a hexadecimal system instead of binary. The binary has two states, the values one or zero, but the hexadecimal has 16, which are the values 0123456789ABCDEF.
An IPv6 address is made up of eight groups of four in hexadecimal. An example of an address would be 1234: abcd: 5678: efab: 9012: cdef: 3456: abcd
This allows for many more combinations than four billion. To be exact, IPv6 allows 340 undecillion IP addresses.
We probably won’t need that much, so the IP address allocation issue is solved!
We will use 192.168.0.1 as an example here. IP addresses are all about the binary. Each of the four blocks of an IP address represents a binary byte. EXPECT! Don’t run away, it’s easy!
11110000 is a binary byte, one byte because there are eight spaces, and binary because each of those spaces will be either a one or a zero. Any sequence of eight digits of ones and zeros is a binary byte.
11111111 is a byte with a value of 255.
00000000 is a byte with a value of 0.
So how do you calculate the decimal value of a byte? It makes sense that eight zeros have a value of zero, but how do eight ones equal 255? Each of the eight positions has an attached value – see the table below. Moving from right to left, the first space has a value of one, the second of two, the third of four, and up to 128.
Essentially, zeros mean off and a few mean on. So the above has a value of 240 because 128 + 64 + 32 + 16 = 240. If you wanted to create a value of one, it would be 00000001. If you wanted a value of three, it would be 00000011. You turn values on or off with a one or zero to create a value, like an abacus.
Remember we said that every block of an IP address is a value between zero and 255? Remember we also said that each block is a byte? Well, that means 192.168.0.1, in binary, looks like 11000000.10110000.0000000000000001. A little heavy, eh? So instead of writing 32 separate numbers, we are writing shorthand. This is what an IP is – a binary shortcut.