Someone recently asked me why their wireless routers always had a default IP address of 192.168.0.1 and I really could not come up with a good answer! Being an IT guy myself, I was obviously irritated by the fact that I hadn’t really thought about something that’s in my face pretty much every day before.
So why do most routers use this IP address? Well, it’s pretty simple actually. The reason is that the IP address is a non-routable IP address. A non-routable IP address, also known as a private IP address, is not assigned to any one particular organization and does not need to be assigned by an Internet Service Provider.
Some will argue that all IP addresses are routable, it’s just specific IP address ranges are not publicly routed on the Internet. Instead, they are routed to a NAT gateway or a proxy server before being connected to the Internet.
Private IP addresses are used in most and small business networks because a ISP usually assigns only one IP address to a location. If there is more than one device that needs to connect to the Internet, a NAT (Network Address Translation) gateway is used to connect to the Internet.
Most of the time, the NAT device is also the router that gives out the private IP addresses to all the computers on the local network.
Officially, there are three private IP address ranges that have been defined by the IANA in:
|10.0.0.0 – 10.255.255.255|
|172.16.0.0 – 172.31.255.25|
|192.168.0.0 – 192.168.255.255|
Any private network in the world is using one of these three IP address ranges for their addressing scheme. The class is determined by the number of usable addresses in that range. Class A has well over 16 million usable addresses and is only needed by extremely large organizations that have hundreds of interconnected networks.
The reason why most routers come setup with a Class C IP address is because it can still handle over 65,000 IP addresses, enough for just about any home or small business.
The first usable address in the Class C network is 192.168.0.1, usually what the router is set to. Note that if you like, you could change the default IP address to either a Class B or Class A network IP and it would still work fine.
There is actually no other difference between the different private IP ranges besides the available addresses.
Note that there are other private IP address ranges, such as 184.108.40.206/8 and 220.127.116.11/8, but they are not being used. The other private IP address you may have seen is 169.254/16. These are called link-local addresses and are only used when there is no DHCP server to assign IP addresses.
The devices will automatically assign an IP address to themselves in the range 169.254.0.0 to 169.254.255.255. This ensures that the devices can still communicate with other another even without a DHCP server or without having to manually assign IP addresses.
Anyway, so hopefully that explains a little bit about why routers have addresses like 192.168.0.1 or 10.0.1.1, etc. I’m sure my explanation was not perfect, so if I made any incorrect statement, please feel free to post a comment! Enjoy!