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IPv6 ULA generator

Generate IPv6 Unique Local Addresses (ULA) per RFC 4193 for private networks. No public registration needed — perfect for home labs and enterprise internal networks.

How to Use

  1. Step 1: Click Generate to create a random IPv6 ULA prefix.
  2. Step 2: The generated prefix, global ID, and full address range are displayed.
  3. Step 3: Copy the prefix to use in your local network configuration.

Frequently Asked Questions

What is an IPv6 ULA address?

ULA (Unique Local Address) is an IPv6 address in the fc00::/7 range similar to private IPv4 ranges. Not routable on the global internet.

How is a ULA global ID generated?

Per RFC 4193 the 40-bit global ID is generated pseudo-randomly to minimize collision probability.

What is the difference between IPv6 ULA and public IPv6?

ULA (fc00::/7 prefix) is like IPv4 private addresses — only routable within your local network. GUA (Global Unicast Address) is publicly routable. ULA provides stable internal addressing independent of ISP assignment, useful even without internet connectivity.

What is the difference between IPv6 ULA and Global Unicast Addresses (GUA)?

ULA (Unique Local Addresses, fc00::/7) are similar to IPv4 private addresses — routed only within the local network and not advertised on the internet. GUA (Global Unicast Addresses, 2000::/3) are globally routable internet addresses. IPv6's abundance of addresses means internal networks can also use GUAs, but ULA is safer for purely internal devices (no internet reachability needed) and is well-suited for labs and development.