nginx auth_error ai_generated true

SSL_do_handshake() failed (SSL: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure) while SSL handshaking to upstream

ID: nginx/ssl-handshake-failed-client-hello

Also available as: JSON · Markdown · 中文
82%Fix Rate
88%Confidence
1Evidence
2024-01-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
nginx 1.20.0 active — — —
nginx 1.22.1 active — — —
nginx 1.25.0 active — — —

Root Cause

TLS handshake failure between nginx and upstream, often due to cipher mismatch, protocol version incompatibility, or certificate validation errors.

generic

中文

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。

Official Documentation

https://nginx.org/en/docs/http/ngx_http_upstream_module.html#proxy_ssl

Workarounds

  1. 80% success Ensure upstream server supports TLS 1.2 or higher. In nginx, set: proxy_ssl_protocols TLSv1.2 TLSv1.3; proxy_ssl_ciphers HIGH:!aNULL:!MD5; This restricts protocols and ciphers to modern versions. 
    Ensure upstream server supports TLS 1.2 or higher. In nginx, set:
proxy_ssl_protocols TLSv1.2 TLSv1.3;
proxy_ssl_ciphers HIGH:!aNULL:!MD5;
This restricts protocols and ciphers to modern versions.
  2. 85% success Check upstream certificate chain: run 'openssl s_client -connect upstream_host:443 -showcerts' to verify certificate validity and intermediate CA completeness. 
    Check upstream certificate chain: run 'openssl s_client -connect upstream_host:443 -showcerts' to verify certificate validity and intermediate CA completeness.
  3. 75% success If upstream uses a self-signed certificate, add its CA to nginx's trust store and set: proxy_ssl_verify on; proxy_ssl_trusted_certificate /path/to/ca.crt; 
    If upstream uses a self-signed certificate, add its CA to nginx's trust store and set:
proxy_ssl_verify on;
proxy_ssl_trusted_certificate /path/to/ca.crt;

中文步骤

  1. Ensure upstream server supports TLS 1.2 or higher. In nginx, set:
proxy_ssl_protocols TLSv1.2 TLSv1.3;
proxy_ssl_ciphers HIGH:!aNULL:!MD5;
This restricts protocols and ciphers to modern versions.
  2. Check upstream certificate chain: run 'openssl s_client -connect upstream_host:443 -showcerts' to verify certificate validity and intermediate CA completeness.
  3. If upstream uses a self-signed certificate, add its CA to nginx's trust store and set:
proxy_ssl_verify on;
proxy_ssl_trusted_certificate /path/to/ca.crt;

Dead Ends

Common approaches that don't work:

  1. 55% fail

    Setting 'proxy_ssl_verify off;' bypasses verification but does not fix the underlying TLS incompatibility; handshake may still fail.

  2. 70% fail

    The issue is usually on the upstream server side; upgrading nginx alone does not fix upstream TLS configuration.

  3. 85% fail

    Restarting does not change TLS settings; if the handshake fails due to cipher mismatch, restarting is ineffective.