IPv6 ULA Generator Online - Create a Random /48 Prefix
Generate a random locally assigned IPv6 Unique Local Address prefix beginning with fd and ending in /48.
About this tool
Five cryptographically random bytes form the locally assigned global ID after the fd prefix, producing a formatted private IPv6 /48 candidate.
How to use
- Enter the value in the format described by the tool.
- Run the conversion or calculation in your browser.
- Review and copy the generated result.
Features
- Generates an fd00::/8 style ULA.
- Uses browser cryptographic randomness.
- Returns a ready-to-copy /48 prefix.
Common use cases
- Plan an internal IPv6 lab.
- Create a ULA prefix for test networks.
- Avoid manually choosing predictable local prefixes.
Common issues and tips
- A generated prefix still requires proper network planning and routing.
- ULA addresses are not intended as globally routable public addresses.
Privacy
Processing runs locally in your browser. Input is not uploaded to Tools12345.
Frequently asked questions
Why does the prefix start with fd?
It marks a locally assigned ULA.
What prefix length is returned?
/48.
Is this a public IPv6 allocation?
No.