Description
Extract bits 11-14 of headerWord as opcode and its top bit as response.
Packet headers encode several meanings in fixed-width fields. Bit positions, network byte order, and reserved values must be distinguished from validation of an entire message.
Extract bits 11-14 of headerWord as opcode and its top bit as response.
When to use this tool
Use DNS Opcode Header Bit Extractor when you need to decode or encode one explicit packet field.
How to use the tool and how it works
- Enter headerWord. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read opcode, response. Inspect response before interpreting the associated values.
Extract bits 11-14 of headerWord as opcode and its top bit as response.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| headerWord | Header Word | Required. Safe integer; minimum 0; maximum 65535. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| opcode | Opcode | Required. Safe integer. |
| response | Response | Required. Boolean. |
json
{
"input": {
"headerWord": 36864
},
"output": {
"opcode": 2,
"response": true
}
}Limitations and assumptions
- The tool does not validate DNS header structure or assigned opcode semantics.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect the complete captured header and apply the relevant protocol's structural and state rules.
References
Similar or alternative tools
- DNS Header Rcode Low Bits
Return the low four bits of flags as rcode.
- DNS NXDOMAIN NODATA Header Distinction
Classify RCODE 3 as nxdomain; RCODE zero becomes noerror-empty-answer or noerror-answer according to answerCount.