DNS Name Relative to Zone
Return exact relative DNS labels only for a name inside an explicitly supplied zone suffix; outside names remain null and case is preserved.
Description
Return exact relative DNS labels only for a name inside an explicitly supplied zone suffix; outside names remain null and case is preserved.
A name can be made relative to a zone only when the zone matches its complete-label suffix. Outside names need an explicit non-match result.
When to use this tool
Return exact relative DNS labels only for a name inside an explicitly supplied zone suffix; outside names remain null and case is preserved.
- Prepare the supplied nameJson, zoneJson 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 nameJson, zoneJson. 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.inside, result.relativeLabels. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Parse nameJson and zoneJson as byte-label arrays. Compare the zone suffix using ASCII case-insensitive label equality; return inside and the original leading labels, or null when outside.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| nameJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
| zoneJson | 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": "nameJson",
"decoded": [
[
97
],
[
98
],
[
99
]
]
},
{
"field": "zoneJson",
"decoded": [
[
98
],
[
99
]
]
}
]| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.inside | Flag for inside under the exact condition described above. |
| result.relativeLabels | The relative labels list in the ordering and representation described above. |
{
"input": {
"nameJson": "[[97],[98],[99]]",
"zoneJson": "[[98],[99]]"
},
"output": {
"result": {
"inside": true,
"relativeLabels": [
[
97
]
]
}
}
}Limitations and assumptions
- An exact zone match returns an empty relative-label list. This tests name structure, not whether a DNS delegation or zone actually exists.
- 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 Name Absolute from Relative
Append explicit relative DNS label octets to a zone’s labels with complete-name byte-budget validation; no resolver, search-list or origin guessing.
- DNS Name Longest Common Suffix
Find the longest complete DNS label suffix shared by two names under ASCII case-insensitive comparison, preserving the left name’s original octets.