IPv6 ULA Generator
Generate IPv6 Unique Local Address
About IPv6 ULA
Unique Local Addresses (ULA) are IPv6 addresses for local communications.
Prefix: fc00::/7 (currently fd00::/8)
They are not routable on the global internet, similar to IPv4 private addresses.
Useful for internal networks, testing, and private communications.
About the Ipv6 Ula Generator
Generate IPv6 Unique Local Addresses (ULA) per RFC 4193. ULAs are the IPv6 equivalent of RFC 1918 private addresses.
Generate a random ULA with the fd00::/8 prefix. Includes the full /48 allocation for your network.
- Generates valid RFC 4193 ULA prefixes (fd00::/8 range)
- Random 40-bit Global ID ensures uniqueness across sites
- Full /48 allocation with 65,536 available subnets
- Supports site-specific subnet IDs (16-bit)
- Copy-paste ready for router and firewall configs
- No network calls — generation is entirely local
How to use
- Click generate.
- Review the ULA and /48 prefix.
- Copy for your network configuration.
Frequently Asked Questions
What is an IPv6 ULA used for? ▾
ULAs are for internal networks that do not need internet routing — homelabs, Docker networks, enterprise LANs, and lab environments. They are the IPv6 equivalent of IPv4 private addresses like 192.168.x.x.
Why fd00::/8 and not fe80::? ▾
fe80:: link-local addresses only work on a single network segment. fd00::/8 ULAs work across routers and VLANs, making them suitable for multi-subnet internal networks.
How do I use the generated address? ▾
The tool gives you a /48 prefix. Assign a /64 from it to each subnet. For example, if your prefix is fd3a:4f5c:6d7e::/48, use fd3a:4f5c:6d7e::/64 for your first subnet, fd3a:4f5c:6d7e:1::/64 for the second, and so on.
Should I use the same ULA on multiple sites? ▾
No — generate a unique ULA per site. The 40-bit random Global ID ensures no collision even if networks merge later. If you need the same ULA across sites connected by VPN, use the same /48.