IPv6 ULA Generator

ULA Prefix (RFC 4193)

How to use this IPv6 ULA generator

  1. Click "Generate New" to create a random ULA prefix.
  2. Use it as the base for your private IPv6 network addressing.
  3. Generate a new one anytime — each is independently randomized.

What is a ULA?

A Unique Local Address is a private IPv6 range (fc00::/7) intended for local networks, similar in spirit to RFC 1918 private IPv4 ranges. The 40-bit global ID is randomly generated so that networks combined later are unlikely to collide.

Can ULA addresses be routed on the public internet?

No, they're designed for private use only, similar to 192.168.x.x in IPv4, and should never appear on the public internet.

Why generate the global ID randomly instead of using a fixed one?

Random generation drastically reduces the chance of address collisions if two separately-configured private networks are ever merged or connected via VPN.