About IPv4 → IPv6 Mapper

IPv4-mapped IPv6 address (::ffff:a.b.c.d) — RFC 4291 representation. Part of the DevTools Surf developer suite. Browse more tools in the Networking collection.

Use Cases

• Network engineers configuring dual-stack server sockets
• DevOps teams setting up IPv4-compatible rules in IPv6 firewalls
• Backend developers handling mixed-protocol client connections
• Cloud architects planning IPv4-to-IPv6 migration strategies

Tips

• Enter an IPv4 address to get its ::ffff: mapped IPv6 form
• Output follows the RFC 4291 IPv4-mapped representation
• Use mapped addresses for dual-stack network configurations

Fun Facts

• IPv4-mapped IPv6 addresses (::ffff:0:0/96) were defined in RFC 4291 (2006) to allow IPv6 applications to communicate with IPv4 hosts without protocol translation.
• The dual-stack approach — running IPv4 and IPv6 simultaneously — was recommended by the IETF over tunneling, and most modern operating systems enable it by default.
• As of 2024, approximately 40% of the top 1000 websites support IPv6, but over 99% of internet domains still have IPv4 addresses configured.

FAQ

What's the mapped form?

::ffff:a.b.c.d — an IPv6 representation that includes an IPv4 address. Used in dual-stack systems where the OS routes IPv4 through IPv6-only code paths.

When would I use this?

Reading server logs from dual-stack systems, or debugging why an IPv6 firewall rule isn't matching IPv4 traffic. Most users never encounter it.

Are there other representations?

::a.b.c.d (deprecated, IPv4-compatible), 2002:... (6to4 transitional), 2001:... (Teredo). The tool converts all of them.

Is the conversion bidirectional?

For IPv4-mapped yes — ::ffff:1.2.3.4 → 1.2.3.4 cleanly. Other IPv6 formats don't always round-trip; the tool is explicit about this.