What is a non-routable IP address range?

Quick answer

Some IP addresses can never appear on the public internet — they’re reserved for private use and routers deliberately won’t forward them. These non-routable ranges are why your home devices can share addresses with millions of others. Here’s how they work.

What “non-routable” means

A non-routable (private) IP is one that public internet routers are configured to ignore — they won’t carry traffic to or from it. These addresses work only inside a local network. To reach the internet, devices using them go through a router that translates their private address into a shared public one (NAT).

The private ranges

Three IPv4 ranges are reserved for private use (RFC 1918): 10.0.0.0–10.255.255.255 (a /8), 172.16.0.0–172.31.255.255 (a /12), and 192.168.0.0–192.168.255.255 (a /16). That last one is why so many home routers use 192.168.1.1. These addresses are reused on countless networks worldwide without conflict, because they never meet on the public internet.

Other reserved addresses

Beyond the private ranges, some addresses are reserved for special purposes: 127.0.0.0/8 is loopback (127.0.0.1 = “this device”), 169.254.0.0/16 is link-local (the APIPA self-assigned addresses that signal a DHCP failure), and 0.0.0.0 and various multicast/reserved blocks have their own roles. None of these route on the public internet either.

Private vs public, side by side

Your devices have private, non-routable IPs inside your network; your router has one public, routable IP facing the internet. When you check your address on our homepage, you see the public one — the routable address the world uses to reach you. Your 192.168.x.x never appears there, because it can’t leave your network.

Why this matters

Understanding routable vs non-routable explains a lot: why your internal IP differs from your public one, why 192.168.1.1 is the same on everyone’s router, and why you can’t reach a device by its private IP from outside without port forwarding. For working with address ranges and prefixes, see CIDR notation explained.