IPv6 to IPv4 Converter

Convert IPv6 addresses back to IPv4 format. Supports IPv4-mapped IPv6, 6to4, Teredo, and other transition mechanisms. Essential for backward compatibility and network troubleshooting.

Important Limitation

Only specific IPv6 address types contain embedded IPv4 information and can be converted back to IPv4. These include:

  • IPv4-mapped IPv6 addresses (::ffff:0:0/96)
  • 6to4 addresses (2002::/16)
  • Teredo addresses (2001::/32)
  • IPv4-compatible addresses (::/96) - deprecated
  • SIIT addresses (64:ff9b::/96)
Enter an IPv6 address containing embedded IPv4 information. Supports compressed (::) and expanded formats.
IPv4-Mapped
IPv4-Mapped Hex
6to4 Address
Teredo Address
SIIT Address
ISATAP Address
Pure IPv6
Converting address...
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Bulk Conversion Tool

Convert multiple IPv6 addresses at once. Enter one IPv6 address per line.

Test Cases

Test various IPv6 address types to see if they can be converted to IPv4:

IPv4-Mapped Address
::ffff:192.168.1.1 → 192.168.1.1
Convertible
6to4 Address
2002:c0a8:101:: → 192.168.1.1
Convertible
Teredo Address
2001:0:c0a8:101:: → 192.168.1.1*
Partial*
Pure IPv6 Address
2001:db8::1 → N/A
Not convertible
SIIT Address
64:ff9b::c0a8:101 → 192.168.1.1
Convertible
ISATAP Address
fe80::5efe:c0a8:101 → 192.168.1.1
Convertible

Understanding IPv6 to IPv4 Conversion

Converting IPv6 addresses back to IPv4 is possible only for specific IPv6 address types that contain embedded IPv4 information. This conversion is essential for backward compatibility and network troubleshooting.

Convertible IPv6 Address Types

IPv6 Address Type Prefix/Range IPv4 Location Convertibility Example
IPv4-mapped ::ffff:0:0/96 Last 32 bits Full ::ffff:192.168.1.1
IPv4-compatible ::/96 Last 32 bits Deprecated ::192.168.1.1
6to4 2002::/16 Bits 16-47 (hextets 1-2) Full 2002:c0a8:101::
Teredo 2001::/32 Bits 32-63 (obfuscated) Partial* 2001:0:c0a8:101::
SIIT 64:ff9b::/96 Last 32 bits Full 64:ff9b::c0a8:101
ISATAP fe80::/10 + 5efe: Last 32 bits Full fe80::5efe:c0a8:101
Pure IPv6 All others N/A None 2001:db8::1

* Teredo addresses include obfuscation; conversion shows the original IPv4 before obfuscation. Real Teredo addresses (RFC 4380) contain additional information not shown here.

Conversion Algorithms

1

IPv4-mapped addresses (::ffff:0:0/96): Extract the last 32 bits. If in IPv4 notation (::ffff:192.168.1.1), parse directly. If in hex notation (::ffff:c0a8:101), convert each hex pair to decimal.

2

6to4 addresses (2002::/16): Extract hextets 1 and 2 (the 32 bits after the 2002: prefix). Convert the 4-hextet value to IPv4 (e.g., c0a8:0101 → 192.168.1.1).

3

Teredo addresses (2001::/32): Extract and de-obfuscate hextets 2 and 3. Teredo uses XOR obfuscation with 0xffffffff, so the original IPv4 is the complement of the embedded value. Note: This is a simplified representation; real Teredo addresses include server address, flags, and UDP port information.

Practical Applications

  • Network Troubleshooting: Identify the original IPv4 address when dealing with transition technologies
  • Log Analysis: Convert IPv6 logs back to IPv4 for compatibility with existing tools
  • Application Migration: Help migrate applications from IPv4 to IPv6 by understanding address relationships
  • Security Analysis: Trace IPv6 connections back to their IPv4 origins
  • Network Planning: Understand IPv6 deployment and transition mechanisms in use

Conversion Tool Features:

  • Supports all major IPv6-to-IPv4 conversion methods
  • Auto-detects address type and applies appropriate conversion
  • Handles both compressed (::) and expanded IPv6 formats
  • Provides binary visualization of the conversion process
  • Includes bulk conversion for processing multiple addresses
  • Shows conversion steps for educational purposes
  • Validates IPv6 addresses and provides helpful error messages
  • Fixed: Corrected 6to4 address conversion logic
  • Enhanced: Improved Teredo address explanation with RFC 4380 reference
  • Added: Web Worker support for non-blocking bulk operations

Frequently Asked Questions

No, only specific IPv6 address types that contain embedded IPv4 information can be converted. These include IPv4-mapped addresses (::ffff:0:0/96), 6to4 addresses (2002::/16), Teredo addresses (2001::/32), and similar transition mechanisms. Pure IPv6 addresses like 2001:db8::1 cannot be converted to IPv4 because they don't contain IPv4 information.

Common scenarios include: troubleshooting networks using transition technologies, analyzing logs that contain mixed IPv4/IPv6 addresses, migrating applications from IPv4 to IPv6, understanding legacy system compatibility, and security investigations where you need to trace connections back to their IPv4 origins.

IPv4-mapped addresses (::ffff:0:0/96) are used to represent IPv4 addresses in IPv6 format and are still in use today. IPv4-compatible addresses (::/96) were an early transition mechanism that has been deprecated by RFC 4291. Both contain IPv4 information in the last 32 bits, but IPv4-compatible addresses should not be used in new deployments.

Teredo addresses include obfuscation to prevent easy extraction of the original IPv4 address. Our tool shows the IPv4 address before obfuscation, which is useful for understanding the transition mechanism. However, in real Teredo deployments (RFC 4380), the address includes additional information: Teredo server IPv4, flags, client UDP port, and the client IPv4 address is XORed with 0xffffffff. For production use and accurate Teredo parsing, refer to RFC 4380.

The tool will detect that the address doesn't contain embedded IPv4 information and will display an error message explaining why conversion is not possible. It will also suggest possible reasons and show the address type detection results. This helps users understand the limitations of IPv6-to-IPv4 conversion.