::ffff:0.0.0.0/96: IPv4-mapped Address address range

::ffff:0.0.0.0/96

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

Short answer

::ffff:0:0/96 holds IPv4 addresses written in IPv6 form (IPv4-mapped addresses).

Block	::ffff:0.0.0.0/96
First – last	::ffff:0:0 – ::ffff:ffff:ffff
Size	a /96 (2^32 addresses)
Name in the registry	IPv4-mapped Address
Defined in	RFC 4291
Allocated	2006-02
Valid as source / destination	False / False
Forwardable	False
Globally reachable	False

What it means

RFC 4291 defines IPv4-mapped IPv6 addresses such as ::ffff:203.0.113.5. Dual-stack software uses this form internally to handle IPv4 connections through an IPv6 socket.

The address inside is the real IPv4 one; peekip shows it without the ::ffff: prefix.

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

Sources

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