Private IP Address Ranges
Complete reference for private, reserved, and special-use IP address ranges. Includes RFC 1918 ranges, IPv6 ULA space, APIPA, and loopback.
RFC 1918 — Private IPv4 Ranges
| Block | Range | Mask | Total IPs | Typical Use |
|---|---|---|---|---|
| 10.0.0.0/8 | 10.0.0.0 – 10.255.255.255 | 255.0.0.0 | 16,777,216 | Enterprises, data centres, cloud VPCs |
| 172.16.0.0/12 | 172.16.0.0 – 172.31.255.255 | 255.240.0.0 | 1,048,576 | Mid-size organisations, Docker default bridge |
| 192.168.0.0/16 | 192.168.0.0 – 192.168.255.255 | 255.255.0.0 | 65,536 | Home networks, small office LANs |
Special-Use IPv4 Ranges (IANA)
| Block | Purpose | RFC |
|---|---|---|
| 127.0.0.0/8 | Loopback — packets never leave the host | RFC 1122 |
| 169.254.0.0/16 | APIPA / Link-local — assigned when DHCP fails | RFC 3927 |
| 100.64.0.0/10 | Carrier-grade NAT (CGNAT) | RFC 6598 |
| 192.0.0.0/24 | IETF Protocol Assignments | RFC 6890 |
| 192.0.2.0/24 | TEST-NET-1 — documentation and examples | RFC 5737 |
| 198.51.100.0/24 | TEST-NET-2 — documentation and examples | RFC 5737 |
| 203.0.113.0/24 | TEST-NET-3 — documentation and examples | RFC 5737 |
| 224.0.0.0/4 | IPv4 Multicast | RFC 5771 |
| 240.0.0.0/4 | Reserved (future use) | RFC 1112 |
| 255.255.255.255/32 | Limited broadcast | RFC 0919 |
| 0.0.0.0/8 | This host on this network | RFC 1122 |
IPv6 Private & Reserved Ranges
| Prefix | Purpose | RFC |
|---|---|---|
| ::1/128 | Loopback — equivalent to 127.0.0.1 | RFC 4291 |
| fe80::/10 | Link-local — auto-assigned, non-routable | RFC 4291 |
| fc00::/7 | Unique Local Addresses (ULA) — private space | RFC 4193 |
| fd00::/8 | ULA — locally assigned range (fd prefix) | RFC 4193 |
| 2001:db8::/32 | Documentation and examples only | RFC 3849 |
| 2002::/16 | 6to4 tunneling | RFC 3056 |
| ff00::/8 | Multicast | RFC 4291 |
| ::/128 | Unspecified address | RFC 4291 |
What is RFC 1918?
RFC 1918, published in 1996, defines three blocks of IPv4 address space reserved for private use. These addresses are guaranteed to never be assigned as public internet addresses, so any device or router connected to the internet will not forward packets destined for them. They are free to use on any internal network, and Network Address Translation (NAT) is used to allow private hosts to access the public internet through a single public IP address.
How to choose between 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16
The key differentiator is address space size. Use 10.0.0.0/8 for large enterprise networks, data
centres, and cloud VPCs where you need millions of addresses across hundreds of subnets. Use
172.16.0.0/12 for medium-sized networks — this is also Docker's default bridge network range. Use
192.168.0.0/16 for home networks and small offices. Avoid overlapping these ranges if you ever plan
to connect multiple sites with VPNs.
What is APIPA (169.254.0.0/16)?
Automatic Private IP Addressing (APIPA) is a Windows feature (also implemented in other OSes) that self-assigns
an address in the 169.254.0.0/16 range when a host fails to obtain an address from a DHCP server.
If you see a 169.254.x.x address on a network interface, it almost always means DHCP is not
reachable — either the DHCP server is down, the network cable is unplugged, or the host is isolated from the
DHCP server by a routing issue.