IPv6 ULA Generator - Free Online IT Tool

🌍 IPv6 ULA Generator

Generate private, non-routable IPv6 Unique Local Addresses (RFC 4193).

ℹ️ About IPv6 ULA Generator

The IPv6 ULA Generator creates private network prefixes according to the RFC 4193 standard. Unlike IPv4, where private ranges are fixed (like 10.0.0.0/8), IPv6 uses Unique Local Addresses (ULA) that are intended to be globally unique but not globally routable.

Each ULA prefix starts with fd followed by a 40-bit random Global ID. This statistical uniqueness ensures that if two private networks are ever merged (e.g., during a company acquisition), the probability of address conflict is extremely low. This tool is essential for architects designing modern, internal-only IPv6 infrastructure.

📖 How to use IPv6 ULA Generator

1. Click 'Run Tool' to generate a new, random /64 ULA prefix.
2. Use the resulting <code>fdxx:xxxx:xxxx::/64</code> network for your internal VLANs or lab environments.
3. Record the 'Global ID' for your network documentation.

❓ Frequently Asked Questions

Is ULA the same as RFC 1918?

Yes, ULAs are the IPv6 equivalent of private IPv4 addresses (like 192.168.x.x). They are used for local communication and cannot be reached from the public internet.

Why is the first byte always 'fd'?

RFC 4193 specifies the <code>fc00::/7</code> block for local addresses. Currently, the 'L' bit must be 1, which results in the <code>fd00::/8</code> prefix being used for locally-generated IDs.