IPv4 to IPv6 Mapper

Build and inspect IPv4-mapped IPv6, RFC 6052 NAT64 embeddings and legacy 6to4 forms with exact bit layouts. Extract the embedded IPv4 again and distinguish representation from real network translation.

Standards-aware · local only

Mapping inputs

IPv4 address

Mapping / representation

NAT64 prefix

Ready.

Mapped address

—

Bit layout

IPv6 analyzer

IPv6 address

NAT64 prefix to test

Ready.

Interpretation

—

One IPv4, many representations

IPv4 address

These strings have different semantics. An IPv4-mapped address is primarily an API/socket representation; a NAT64 address participates in a translation architecture; 6to4 is a legacy transition form. Converting notation does not itself provide connectivity.

Matrix

RFC 6052 correctness

Supported prefix lengths are /32, /40, /48, /56, /64 and /96. For prefixes shorter than /96 the reserved “u” octet at bits 64–71 is kept zero and the IPv4 bits are placed around it exactly as specified.

The well-known NAT64 prefix is 64:ff9b::/96. Custom network-specific prefixes are also supported.

Legacy forms

IPv4-compatible IPv6 addresses under ::/96 are deprecated. 6to4 remains useful for understanding legacy addresses, but public anycast relay service was deprecated and should not be treated as a recommended deployment path.