IPv6 ULA Generator

Generate IPv6 Unique Local Addresses

Generate IPv6 ULA (Unique Local Address) prefixes for private networks. Create RFC 4193 compliant fc00::/7 addresses. Free IPv6 ULA generator.

Global ID (40-bit)

RandomCustom

1a5a03a46d

Subnet ID (16-bit)

4 hex characters (0000-ffff). Use 0000 for first subnet, increment for additional subnets.

Generated ULA

/64 Prefixfd1a:5a03:a46d:0000::/64

/48 Prefixfd1a:5a03:a46d::/48

Example Addressfd1a:5a03:a46d:0000::1

Range Startfd1a:5a03:a46d:0000:0000:0000:0000:0001

Range Endfd1a:5a03:a46d:0000:ffff:ffff:ffff:fffe

ULA Breakdown

fd1a5a03a46d0000::/64

PrefixGlobal ID (40-bit)Subnet (16-bit)Interface ID (64-bit)

About IPv6 ULA

Unique Local Addresses (ULA) are IPv6 addresses for private networks, similar to IPv4's private address ranges (10.x.x.x, 192.168.x.x).

Prefix: fd00::/8 (the 'fd' prefix indicates locally assigned ULA)

Global ID: 40-bit random identifier. Should be generated randomly to minimize collision probability if networks merge.

Subnet ID: 16-bit field for up to 65,536 subnets per site.

RFC 4193: Defines the ULA format and generation algorithm.