IPv6 Mapped IPv4 Payload Builder
Build the exact IPv4-mapped IPv6 address for a validated IPv4 payload, formatted fully expanded; not NAT64 or an interface assignment.
Description
Build the exact IPv4-mapped IPv6 address for a validated IPv4 payload, formatted fully expanded; not NAT64 or an interface assignment.
An IPv4-mapped IPv6 address has an exact 96-bit prefix followed by the IPv4 payload. This representation is distinct from arbitrary address embeddings.
When to use this tool
Build the exact IPv4-mapped IPv6 address for a validated IPv4 payload, formatted fully expanded; not NAT64 or an interface assignment.
- Prepare the supplied ipv4 fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter ipv4. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.address. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Validate ipv4, convert its 32 bits to an integer, combine it with 65535 shifted left 32 bits and format all eight IPv6 hextets with four lowercase hexadecimal digits.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| ipv4 | Address text for the family named by this tool. Prefix lengths are separate fields where shown. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.address | The address value under the stated formula or text convention. |
{
"input": {
"ipv4": "192.0.2.1"
},
"output": {
"result": {
"address": "0000:0000:0000:0000:0000:ffff:c000:0201"
}
}
}Limitations and assumptions
- This creates address text, without NAT64 translation, address assignment or connectivity testing.
- IPv4 input uses strict dotted-decimal octets without leading zeros or surrounding whitespace. IPv6 accepts its supported compressed or full spellings and trims surrounding whitespace, but rejects zone identifiers; embedded dotted IPv4 uses the strict IPv4 spelling. IPv6 address outputs are fully expanded unless stated otherwise.
- All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
- JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.
Alternative or Complementary methods
Use address-set arithmetic for prefix planning and a routing or interface inspection for deployed configuration. Membership and overlap do not establish reachability, ownership or route preference.
References
Similar or alternative tools
- IPv6 Mapped IPv4 Payload Extractor
Extract an IPv4 payload only from the exact IPv4-mapped IPv6 ::ffff:0:0/96 format; other embeddings are not guessed.
- Integer String IPv6 Address
Format an exact unsigned 128-bit decimal integer as fully expanded lowercase IPv6 using the existing group formatter.