FA-7336 / DNS resolution / Open access

Dns response correlates identifier and question · case 01

Dns response correlates identifier and question.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The faulty implementation uses `sent[0] == received[0] and peer == expected_peer` for the dns-response-correlates-identifier-and-question decision.

VERIFIED REPAIR

Apply the explicit dns-response-correlates-identifier-and-question contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `sent == received` and still violates a separate fixture.

Case contract

Given sent, received, peer, expected_peer, dns response correlates identifier and question. Return the protocol decision or transformed value; fields are validated and fixtures state boundary outcomes.

Why this case matters

This deterministic dns resolution model isolates the dns-response-correlates-identifier-and-question policy at a network component boundary.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(sent, received, peer, expected_peer):
    return sent[0] == received[0] and peer == expected_peer
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve((1, 'a'), (1, 'b'), 'ns', 'ns'), False)", "check('fixture 2', solve((1, 'a'), (1, 'a'), 'evil', 'ns'), False)", "check('fixture 3', solve((1, 'a'), (1, 'a'), 'ns', 'ns'), True)", "check('fixture 4', solve((1, 'a'), (2, 'a'), 'ns', 'ns'), False)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`False`	`False`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / 4eeaa2f2c61226fb414df1f08c383f852a3e487571a48030f70c91a41695dd8e

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(sent, received, peer, expected_peer):
    return sent == received
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve((1, 'a'), (1, 'b'), 'ns', 'ns'), False)", "check('fixture 2', solve((1, 'a'), (1, 'a'), 'evil', 'ns'), False)", "check('fixture 3', solve((1, 'a'), (1, 'a'), 'ns', 'ns'), True)", "check('fixture 4', solve((1, 'a'), (2, 'a'), 'ns', 'ns'), False)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`True`	`False`	Failed
fixture 3	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / b7695d91ebf31ac0827ff5eda252253a3d95935e5516a7fa91550ab2034eacf3

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(sent, received, peer, expected_peer):
    return sent == received and peer == expected_peer
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve((1, 'a'), (1, 'b'), 'ns', 'ns'), False)", "check('fixture 2', solve((1, 'a'), (1, 'a'), 'evil', 'ns'), False)", "check('fixture 3', solve((1, 'a'), (1, 'a'), 'ns', 'ns'), True)", "check('fixture 4', solve((1, 'a'), (2, 'a'), 'ns', 'ns'), False)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`False`	`False`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / ddb1b8140d996d4a40fbd58d0f795115cb216531679eff32489e5090b23b50dc

Verification & scope

Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:10.739807+00:00.

Case digest / be688330c4add9dda34d68bf61954bc091dbfe2e79e70af5847369580ec1b66d