{
  "id": "networking/dns-dangling-cname",
  "signature": "DNS: CNAME resolution loop detected for www.example.com (max depth 16 exceeded)",
  "signature_zh": "DNS: 检测到www.example.com的CNAME解析循环（超过最大深度16）",
  "regex": "DNS: CNAME resolution loop detected for [\\w.]+ \\(max depth \\d+ exceeded\\)",
  "domain": "networking",
  "category": "protocol_error",
  "subcategory": null,
  "root_cause": "A DNS zone contains a chain of CNAME records that ultimately points back to itself, creating an infinite loop that exceeds the resolver's maximum query depth (typically 16) and causes a resolution failure.",
  "root_cause_type": "generic",
  "root_cause_zh": "DNS区域中包含一条CNAME记录链，最终指向自身，形成无限循环，超过解析器的最大查询深度（通常为16），导致解析失败。",
  "versions": [
    {
      "version": "BIND 9.18.12",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "Unbound 1.17.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "PowerDNS Authoritative Server 4.8.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "The loop is in the authoritative DNS zone, not in the client cache; flushing will just re-fetch the same broken records.",
      "fail_rate": 0.98,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "This only delays the failure; the loop will eventually hit the new limit and still fail. It also increases resource usage for legitimate queries.",
      "fail_rate": 0.85,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "This is too aggressive; the loop is caused by a specific CNAME chain, not all records. Removing everything may break other services.",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Identify and break the CNAME loop by inspecting the zone file: dig www.example.com CNAME +trace; then remove or correct the circular reference in the DNS provider's control panel.",
      "success_rate": 0.95,
      "how": "Identify and break the CNAME loop by inspecting the zone file: dig www.example.com CNAME +trace; then remove or correct the circular reference in the DNS provider's control panel.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Temporarily replace the CNAME record with an A record pointing to the correct IP address to restore service while investigating the loop.",
      "success_rate": 0.9,
      "how": "Temporarily replace the CNAME record with an A record pointing to the correct IP address to restore service while investigating the loop.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Use a DNS debugging tool like dnstracer to visualize the CNAME chain: dnstracer www.example.com -s . -r 20",
      "success_rate": 0.88,
      "how": "Use a DNS debugging tool like dnstracer to visualize the CNAME chain: dnstracer www.example.com -s . -r 20",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Identify and break the CNAME loop by inspecting the zone file: dig www.example.com CNAME +trace; then remove or correct the circular reference in the DNS provider's control panel.",
    "Temporarily replace the CNAME record with an A record pointing to the correct IP address to restore service while investigating the loop.",
    "Use a DNS debugging tool like dnstracer to visualize the CNAME chain: dnstracer www.example.com -s . -r 20"
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://www.rfc-editor.org/rfc/rfc1034#section-5.2.2",
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.9,
  "fix_success_rate": 0.95,
  "resolvable": "true",
  "first_seen": "2024-01-10",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}