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What Is IPv4 to IPv6 Conversion
IPv4 (Internet Protocol version 4) uses 32-bit addresses providing approximately 4.3 billion unique addresses — a pool that has been exhausted since 2011. IPv6 uses 128-bit addresses, providing 340 undecillion (3.4 x 10^38) addresses — enough to assign a unique address to every atom on the surface of the Earth and still have addresses left over.
Converting and mapping between IPv4 and IPv6 addresses is essential during the ongoing global transition from IPv4 to IPv6. Organizations must support both protocols simultaneously (dual-stack), translate between them, and understand how IPv4 addresses are represented within IPv6 space.
Address Format Comparison
| Feature | IPv4 | IPv6 |
|---|---|---|
| Address length | 32 bits | 128 bits |
| Notation | Dotted decimal (192.168.1.1) | Colon hexadecimal (2001:0db8::1) |
| Address space | ~4.3 billion | ~340 undecillion |
| Header size | 20-60 bytes (variable) | 40 bytes (fixed) |
| Broadcast | Yes | No (replaced by multicast) |
| IPsec | Optional | Built-in (mandatory to implement) |
| NAT required | Typically yes | No — enough addresses for direct connectivity |
| Checksum | In header | Removed (handled by link and transport layers) |
IPv4-Mapped IPv6 Addresses
IPv4 addresses can be represented within IPv6 address space using special mapping formats:
| Type | Format | Example |
|---|---|---|
| IPv4-Mapped | ::ffff:IPv4 | ::ffff:192.168.1.1 or ::ffff:c0a8:0101 |
| IPv4-Compatible | ::IPv4 (deprecated) | ::192.168.1.1 |
| 6to4 | 2002:IPv4::/48 | 2002:c0a8:0101::/48 |
| NAT64 | 64:ff9b::IPv4 | 64:ff9b::192.168.1.1 |
Common Use Cases
- Network migration planning: Convert IPv4 address schemes to IPv6 equivalents when planning dual-stack deployments
- Firewall rule translation: Convert IPv4-based firewall rules and access control lists to their IPv6 equivalents
- DNS configuration: Set up AAAA records (IPv6) alongside A records (IPv4) for dual-stack web servers
- Application development: Ensure applications handle both address formats correctly, including storage, validation, and display
- Troubleshooting: Convert between formats when analyzing logs that mix IPv4 and IPv6 addresses
Best Practices
- Plan for dual-stack — The transition period requires supporting both IPv4 and IPv6 simultaneously. Dual-stack (native support for both protocols) is preferred over translation mechanisms.
- Use IPv4-mapped addresses correctly — ::ffff:0:0/96 is for internal use by dual-stack systems. Do not use IPv4-mapped addresses on the wire or in DNS records.
- Simplify IPv6 addresses — Use zero compression (::) and remove leading zeros for readability. 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1.
- Update applications and libraries — Ensure your code uses address-family-independent APIs (getaddrinfo instead of gethostbyname) to support both IPv4 and IPv6.
- Test IPv6 connectivity — Many networks still lack full IPv6 support. Test your services over IPv6-only connections to ensure they work without IPv4 fallback.
Frequently Asked Questions
Common questions about the IPv4/IPv6 Converter
This tool converts IP addresses between IPv4 and IPv6 formats. For IPv4 addresses, it generates IPv4-mapped IPv6 addresses in both dotted and hexadecimal notation, as well as 6to4 transition addresses. For IPv6 addresses, it provides full and compressed forms, identifies the address type, and extracts embedded IPv4 addresses when present.
ℹ️ Disclaimer
This tool is provided for informational and educational purposes only. All processing happens entirely in your browser - no data is sent to or stored on our servers. While we strive for accuracy, we make no warranties about the completeness or reliability of results. Use at your own discretion.