Sign inMonitor a domain
ff00::/8

ff00

Last updated 2 Nov 2026 from the IANA IPv6 Special-Purpose Address Registry

Short answer

ff00::/8 is IPv6 multicast.

Blockff00::/8
First – lastff00:: – ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Sizea /8 (2^120 addresses)
Name in the registryMulticast
Defined inRFC 4291

What it means

RFC 4291 reserves ff00::/8 for multicast groups, for example ff02::1 (all nodes on the link).

A multicast address never identifies one device or person.

Want the address websites actually see for you? Open the Truth Check.

Sources

  1. IANA IPv6 Special-Purpose Address Registry (CC0) · checked 2 Nov 2026
  2. RFC 4291