guest@ipterm:~$ man private-ip
Private IP address ranges explained
Some IP addresses are reserved for use inside local networks and are never routed on the public internet. Your laptop, phone and router almost certainly use one of them right now, and they look the same in millions of homes and offices.
The three private ranges (RFC 1918)
| Block | Range | Addresses |
|---|---|---|
| 10.0.0.0/8 | 10.0.0.0 – 10.255.255.255 | 16,777,216 |
| 172.16.0.0/12 | 172.16.0.0 – 172.31.255.255 | 1,048,576 |
| 192.168.0.0/16 | 192.168.0.0 – 192.168.255.255 | 65,536 |
Home routers usually hand out 192.168.x.x addresses. Larger networks and many provider gateways use 10.x.x.x. Note that 172.16 through 172.31 is private, but 172.32 and above is ordinary public address space.
Why private addresses can't be looked up
Your router translates between your private addresses and the single public address your provider gives you. This is called NAT (network address translation). Websites only ever see the public address, which is what whoami shows. A private address has no owner on the internet and no location, so a lookup can only tell you which range it belongs to.
Other special ranges you may see
| Block | Name | What it means |
|---|---|---|
| 127.0.0.0/8 | Loopback | Your own device. 127.0.0.1 is "this computer". |
| 169.254.0.0/16 | Link-local | The device asked for an address and got no answer, usually a DHCP problem. |
| 100.64.0.0/10 | Carrier-grade NAT (RFC 6598) | Your provider shares one public address among many customers. |
| 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24 | Documentation (RFC 5737) | Reserved for examples in manuals and articles. |
| 224.0.0.0/4 | Multicast | One sender, many receivers, such as streaming on a local network. |
| 240.0.0.0/4 | Reserved | Set aside and not used on the public internet. |
IPv6 equivalents
- fc00::/7 (in practice fd00::/8): unique local addresses, the IPv6 version of private ranges.
- fe80::/10: link-local, present on every IPv6 interface.
- ::1: loopback.
Most IPv6 devices also have a public, globally routable address, so NAT is far less common with IPv6. See IPv4 vs IPv6.
Try itLook up 10.0.0.1, 172.16.0.1 or 100.64.0.1 to see how ipterm labels each range.