Well-Known IPv4 Networks

These ranges cause most real-world addressing problems: home router defaults that break VPNs, Docker networks that hide corporate hosts, and CGNAT space that blocks port forwarding. Each page explains who uses the range, what it clashes with, and how to split it.

10.0.0.0/8 The Largest Private Range 10.0.0.0 – 10.255.255.255 · 16,777,214 usable · Private (RFC 1918) 127.0.0.0/8 The Loopback Range 127.0.0.0 – 127.255.255.255 · 16,777,214 usable · Loopback (RFC 1122) 100.64.0.0/10 Carrier-Grade NAT Space 100.64.0.0 – 100.127.255.255 · 4,194,302 usable · Carrier-grade NAT (RFC 6598) 172.16.0.0/12 The Middle Private Range 172.16.0.0 – 172.31.255.255 · 1,048,574 usable · Private (RFC 1918) 169.254.0.0/16 Link-Local Addresses 169.254.0.0 – 169.254.255.255 · 65,534 usable · Link-local / APIPA (RFC 3927) 172.17.0.0/16 Docker's Default Bridge 172.17.0.0 – 172.17.255.255 · 65,534 usable · Private (RFC 1918) 192.168.0.0/16 The Home Network Range 192.168.0.0 – 192.168.255.255 · 65,534 usable · Private (RFC 1918) 10.0.0.0/24 The First /24 of the 10 Range 10.0.0.0 – 10.0.0.255 · 254 usable · Private (RFC 1918) 192.168.0.0/24 The Other Default Home Network 192.168.0.0 – 192.168.0.255 · 254 usable · Private (RFC 1918) 192.168.1.0/24 The Most Common Home Network 192.168.1.0 – 192.168.1.255 · 254 usable · Private (RFC 1918)

Check your own ranges

Paste your office, VPN, cloud and container ranges into the subnet overlap checker to find clashes before they cause an outage. For the maths behind any prefix length, see the prefix reference /8 to /32.