IPv6 ULA generator
Generates an IPv6 Unique Local Address (ULA) prefix per RFC 4193 for local networks — handy for addressing internal devices.
Generate your own local, non-routable IP addresses for your network according to RFC4193.
Steps and notes
What is IPv6 ULA generator?
A ULA (Unique Local Address) is the IPv6 counterpart of the private IPv4 ranges: addresses under fd00::/8 that are free to use inside your organisation but must not be routed on the public internet. RFC 4193 asks for a randomly chosen 40-bit global ID so independently generated prefixes almost never collide, and that is exactly what this tool generates.
- Click generate to get a prefix
- Combine it with a subnet and interface ID as needed
- Copy and use it
- A ULA is the IPv6 counterpart of a private IPv4 range and must not be routed on the public internet
Frequently asked questions
- ULA vs public IPv6 — what is the difference?
- Public addresses are globally routable and assigned by your provider. ULAs work only inside your network, never leave your router, and survive provider changes — good for infrastructure that should not be exposed.
- Why generate the prefix randomly instead of picking fd00::1?
- RFC 4193 mandates a random global ID precisely so two sites that later merge their networks will not clash. Hand-picked prefixes like fd00::/64 are a common source of hard-to-debug conflicts.
- Can a ULA reach the internet?
- No. Routers must not forward fd00::/8 to the public internet. Use it for internal services; hosts still get global addresses from your provider for outbound traffic.
Category: Network
Network & IP workflow
IPv4 Subnet Calculator → IPv4 range expander → IPv4 address converter → IPv6 ULA generator → MAC address generator → MAC address lookup → WHOIS lookup