IPv6 ULA Generator
Free online IPv6 ULA generator, no installation required. Generate unique local addresses per RFC4193
About IPv6 ULA Generator
Generates random IPv6 Unique Local Addresses (ULA) in the fc00::/7 range using the Web Crypto API (crypto.getRandomValues). Each address is fixed to the fd00::/8 locally-assigned prefix with a randomized 40-bit global ID, and the output is shortened using IPv6 zero-compression rules. You can generate 1 to 50 addresses at once.
How to Use
1. Set the Count (default 5, range 1-50). 2. Click Generate. The addresses appear in a monospace block. 3. Use Copy to copy all generated addresses, one per line, to the clipboard.
ULA Address Structure
Per RFC 4193, a ULA starts with fd, followed by a random 40-bit global ID. This generator sets the first byte to 0xfd, forces the L (local) bit in the second byte, and fills the rest with cryptographically random bytes. The address is then compressed by stripping leading zeros and collapsing the longest run of consecutive zero groups to ::.
▶Are these ULA addresses globally unique?
▶Why do the addresses always start with fd?
▶How many addresses can I generate at once?
▶Are the random bytes cryptographically secure?
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