Someone in my office recently asked me why their wireless routers always have a default IP address of 192.168.0.1 or 192.168.1.1, and I really couldn’t find a good answer! I was an IT guy myself, and I was clearly annoyed by the fact that I didn’t really think all the time about what was on my face.
So why do most routers use this IP address? Well, it’s actually pretty simple. This is because the IP address is not a routable IP address. A non-routable IP address, also known as a private IP address, is not assigned to any one organization and should not be assigned by an ISP.
Some will argue that all IP addresses are routable, it is just that certain ranges of IP addresses are not publicly routed on the Internet. Instead, they are routed through a NAT gateway or proxy server before connecting to the Internet.
Private IP addresses are used on most networks of large and small businesses because the ISP usually only assigns one public IP address to a location. Almost all IPv4 addresses have been depleted and therefore we have to rely so much on private IP addresses. When IPv6 eventually arrives, everyone will have a public IP address for each device, but that’s still a long way off.
If there are multiple devices that need to connect to the Internet with only one public IP address, a NAT (Network Address Translation) gateway is used to translate all private IP addresses to a public IP address before going online. In most cases, the NAT device is also a router that issues private IP addresses to all computers on the local network (DHCP server).
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There are officially three ranges of private IP addresses defined by IANA in RFC 1918:
| IP range | Number of addresses | Class |
| 10.0.0.0 – 10.255.255.255 | 16,777,216 | Class A |
| 172.16 .0.0 – 172.31.255.25 | 1 048 576 | Class B |
| 192.168.0.0 – 192.168.255.255 | 65 536 | Class C |
Every private network in the world uses one of these three IP address ranges for its addressing scheme. The class is determined by the number of used addresses in this range. Class A has over 16 million usable addresses and is only needed by very large organizations with hundreds of interconnected networks.
The reason most routers are installed with a Class C IP address is because it can still handle over 65,000 IP addresses, which is enough for just about any home or small business.
The first used address on a Class C network is 192.168.0.1, which is usually the value set for the router. However, in recent years, I’ve noticed that more brands are starting to use 192.168.1.1 as their default IP, perhaps because it’s easier to remember. Note that you can change the default IP address to either Class B or Class A network IP if you wish and it will still work fine.
There is really no other difference between different ranges of private IP addresses other than the number of addresses available.
Note that there are other private IP ranges, such as 1.0.0.0/8 and 2.0.0.0/8, but they are not used. You may have seen other private IP addresses: 169.254.x.x / 16 and 127.x.x.x / 8. These are called APIPA addresses and loopback addresses, respectively.
APIPA addresses are used only when there is no DHCP server to assign IP addresses. The devices automatically assign themselves an IP address in the range 169.254.0.0 to 169.254.255.255. This ensures that devices can communicate with each other even without a DHCP server or the need to manually assign IP addresses.
A loopback address is assigned to all network cards and is used to test the card.
Anyway, hopefully this explains a little why routers have addresses like 192.168.0.1 or 10.0.1.1, etc. I’m sure my explanation wasn’t perfect, so if I made any wrong statement please feel free to leave a comment! Enjoy!
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