DNS Label ASCII Case Normalizer
Canonicalize DNS ASCII uppercase octets only, leaving non-ASCII bytes unchanged; does not apply Unicode lowercase or IDNA mappings.
Description
Canonicalize DNS ASCII uppercase octets only, leaving non-ASCII bytes unchanged; does not apply Unicode lowercase or IDNA mappings.
DNS ASCII case normalization changes uppercase letter octets while preserving other byte values. It is distinct from Unicode lowercase mapping.
When to use this tool
Canonicalize DNS ASCII uppercase octets only, leaving non-ASCII bytes unchanged; does not apply Unicode lowercase or IDNA mappings.
- Prepare the supplied labelsJson 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 labelsJson. 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.labels. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Parse labelsJson as valid nonempty DNS byte labels. Replace values 65 through 90 by their value plus 32 and retain every other octet.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| labelsJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
For the JSON text fields, the following decoded structures show the example records before they are serialized into input strings. Keep field names, list nesting and value types as shown.
[
{
"field": "labelsJson",
"decoded": [
[
65,
90,
192
]
]
}
]| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.labels | The labels list in the ordering and representation described above. |
{
"input": {
"labelsJson": "[[65,90,192]]"
},
"output": {
"result": {
"labels": [
[
97,
122,
192
]
]
}
}
}Limitations and assumptions
- No Unicode decoding or IDNA conversion is performed. The result is a byte-label list, without resolver or zone validation.
- 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 a packet-aware DNS parser or resolver when the task requires compression-chain validation, live records or complete resource-record semantics. Keep byte labels, presentation text and network packets distinct.
References
Similar or alternative tools
- DNS Label Byte Budget Audit
Audit supplied DNS label byte lengths and total uncompressed wire-name budget independently; no text character count or IDNA assumption.
- DNS Label Canonical Order Compare
Compare DNS names in canonical label order from the root/rightmost label outward using lowercase unsigned octets; no Unicode collation or locale sorting.