{"abstract":"Dns negative ttl is minimum of soa ttl and minimum field.","category":"DNS resolution","checks":4,"contract":"Bounded offline decision model: dns negative ttl is minimum of soa ttl and minimum field. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-dns-negative-ttl-is-minimum-of-soa-ttl-and-minimum-field","failed_approach":"The attempted repair uses `max(soa_ttl,minimum)` and still violates a separate fixture.","family":"xh-dns-negative-ttl-is-minimum-of-soa-ttl-and-minimum-field","id":"FA-7351","implementations":{"attempt":{"sha256":"eec872345dfe11ba8e0a24092ffdf9df7fa503a23cb7c36ce00636366bf757ce","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(soa_ttl, minimum):\n    return max(soa_ttl,minimum)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(300, 60), 60)\", \"check('fixture 2', solve(30, 60), 30)\", \"check('fixture 3', solve(0, 60), 0)\", \"check('fixture 4', solve(60, 60), 60)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"e427e0909b8bccafcc979952df6c7c4c96d8067e6c9cf089e4e79a0391c5d368","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(soa_ttl, minimum):\n    return soa_ttl\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(300, 60), 60)\", \"check('fixture 2', solve(30, 60), 30)\", \"check('fixture 3', solve(0, 60), 0)\", \"check('fixture 4', solve(60, 60), 60)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"62e8d57cac23ab21af455fd3d5bebec2fc568042eac34b937b1700baf8b68492","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(soa_ttl, minimum):\n    return min(soa_ttl,minimum)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(300, 60), 60)\", \"check('fixture 2', solve(30, 60), 30)\", \"check('fixture 3', solve(0, 60), 0)\", \"check('fixture 4', solve(60, 60), 60)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xh-dns-negative-ttl-is-minimum-of-soa-ttl-and-minimum-field","generated_at":"2026-09-29T14:38:10.909650+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic dns resolution model isolates the dns-negative-ttl-is-minimum-of-soa-ttl-and-minimum-field policy at a network component boundary.","repair":"Apply the explicit dns-negative-ttl-is-minimum-of-soa-ttl-and-minimum-field contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `soa_ttl` for the dns-negative-ttl-is-minimum-of-soa-ttl-and-minimum-field decision.","sha256":"f77a6bb73e9295bdc7f88e01dee8757a38a5c8cc125be35e2ddef8f676a9ba10","title":"Dns negative ttl is minimum of soa ttl and minimum field · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":44.852,"exit_code":1,"observations":[{"actual":60,"check":"fixture 2","expected":30,"passed":false},{"actual":60,"check":"fixture 3","expected":0,"passed":false},{"actual":60,"check":"fixture 4","expected":60,"passed":true},{"actual":300,"check":"fixture 1","expected":60,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 60, \"expected\": 30, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 60, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 60, \"expected\": 60, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 300, \"expected\": 60, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":47.145,"exit_code":1,"observations":[{"actual":30,"check":"fixture 2","expected":30,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":60,"check":"fixture 4","expected":60,"passed":true},{"actual":300,"check":"fixture 1","expected":60,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 30, \"expected\": 30, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 60, \"expected\": 60, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 300, \"expected\": 60, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":45.26,"exit_code":0,"observations":[{"actual":30,"check":"fixture 2","expected":30,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":60,"check":"fixture 4","expected":60,"passed":true},{"actual":60,"check":"fixture 1","expected":60,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 30, \"expected\": 30, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 60, \"expected\": 60, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 60, \"expected\": 60, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}