{
  "id": "nginx/ssl-handshake-failed-client-hello",
  "signature": "SSL_do_handshake() failed (SSL: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure) while SSL handshaking to upstream",
  "signature_zh": "SSL握手失败",
  "regex": "SSL_do_handshake\\(\\) failed \\(SSL: error:14094410",
  "domain": "nginx",
  "category": "auth_error",
  "subcategory": null,
  "root_cause": "TLS handshake failure between nginx and upstream, often due to cipher mismatch, protocol version incompatibility, or certificate validation errors.",
  "root_cause_type": "generic",
  "root_cause_zh": "nginx与上游之间的TLS握手失败，通常由密码套件不匹配、协议版本不兼容或证书验证错误引起。",
  "versions": [
    {
      "version": "nginx 1.20.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "nginx 1.22.1",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "nginx 1.25.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Setting 'proxy_ssl_verify off;' bypasses verification but does not fix the underlying TLS incompatibility; handshake may still fail.",
      "fail_rate": 0.55,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "The issue is usually on the upstream server side; upgrading nginx alone does not fix upstream TLS configuration.",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Restarting does not change TLS settings; if the handshake fails due to cipher mismatch, restarting is ineffective.",
      "fail_rate": 0.85,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Ensure upstream server supports TLS 1.2 or higher. In nginx, set:\nproxy_ssl_protocols TLSv1.2 TLSv1.3;\nproxy_ssl_ciphers HIGH:!aNULL:!MD5;\nThis restricts protocols and ciphers to modern versions.",
      "success_rate": 0.8,
      "how": "Ensure upstream server supports TLS 1.2 or higher. In nginx, set:\nproxy_ssl_protocols TLSv1.2 TLSv1.3;\nproxy_ssl_ciphers HIGH:!aNULL:!MD5;\nThis restricts protocols and ciphers to modern versions.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Check upstream certificate chain: run 'openssl s_client -connect upstream_host:443 -showcerts' to verify certificate validity and intermediate CA completeness.",
      "success_rate": 0.85,
      "how": "Check upstream certificate chain: run 'openssl s_client -connect upstream_host:443 -showcerts' to verify certificate validity and intermediate CA completeness.",
      "condition": "",
      "sources": []
    },
    {
      "action": "If upstream uses a self-signed certificate, add its CA to nginx's trust store and set:\nproxy_ssl_verify on;\nproxy_ssl_trusted_certificate /path/to/ca.crt;",
      "success_rate": 0.75,
      "how": "If upstream uses a self-signed certificate, add its CA to nginx's trust store and set:\nproxy_ssl_verify on;\nproxy_ssl_trusted_certificate /path/to/ca.crt;",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Ensure upstream server supports TLS 1.2 or higher. In nginx, set:\nproxy_ssl_protocols TLSv1.2 TLSv1.3;\nproxy_ssl_ciphers HIGH:!aNULL:!MD5;\nThis restricts protocols and ciphers to modern versions.",
    "Check upstream certificate chain: run 'openssl s_client -connect upstream_host:443 -showcerts' to verify certificate validity and intermediate CA completeness.",
    "If upstream uses a self-signed certificate, add its CA to nginx's trust store and set:\nproxy_ssl_verify on;\nproxy_ssl_trusted_certificate /path/to/ca.crt;"
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://nginx.org/en/docs/http/ngx_http_upstream_module.html#proxy_ssl",
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.88,
  "fix_success_rate": 0.82,
  "resolvable": "true",
  "first_seen": "2024-01-10",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}