IPv4 to IPv6 Mapper
Convert an IPv4 address to its IPv6 representations.
What you provide
Result
192.168.1.1 → ::ffff:c0a8:101
The IPv4-mapped form (::ffff:) is the one in active use; a dual-stack system represents IPv4 connections this way. The IPv4-compatible form (::) is deprecated and shown only for completeness.
- IPv4-mappedWhat dual-stack sockets use — the one you usually want
- ::ffff:c0a8:101
- IPv4-mapped (mixed)Same address, written with the dotted IPv4 tail
- ::ffff:192.168.1.1
- 6to4 prefixFor 6to4 tunnelling
- 2002:c0a8:101::/48
- IPv4-compatibleDeprecated — do not use
- ::c0a8:101
What this cannot tell you
- Arithmetic on the address you enter. IPv4 only as input.
- The IPv4-compatible form is deprecated and shown only for reference — do not use it.
Take this with you
How this calculation works
The two halves of an IPv4 address become two 16-bit hextets, which slot into several standard IPv6 formats. The tool shows each — the mapped form used by dual-stack systems, the 6to4 tunnelling prefix, and the deprecated compatible form.
What the results mean
- IPv4-mapped
- ::ffff: followed by the address. How a dual-stack socket represents an IPv4 connection internally. The form you almost always want.
- 6to4 prefix
- A 2002::/16 prefix embedding the IPv4, used by the 6to4 tunnelling mechanism.
- IPv4-compatible
- The old :: form. Deprecated by RFC 4291 and shown only so you recognise it, not so you use it.
Frequently asked questions
Which IPv6 form should I use?
The IPv4-mapped form, ::ffff:x. It is what dual-stack operating systems use to represent IPv4 connections, and it is the one you will see in logs and socket APIs. The IPv4-compatible form was deprecated years ago and should never be used in new work.
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