Introduction
SSL/TLS handshake failures can bring your services to a halt. This guide walks developers, engineers, and DevOps professionals through the most common reasons and provides concrete, repeatable fixes.
Common Causes
- Expired or self‑signed certificates
- Incomplete certificate chain
- Hostname mismatch
- Out‑of‑date trust store or protocol version
- Cipher suite incompatibility
Step‑by‑Step Troubleshooting
- Inspect the server certificate chain
openssl s_client -connect example.com:443 -servername example.com -showcerts
Look for Verify return code: 0 (ok). Any error lines indicate missing intermediate certificates.
- Validate hostname matching
echo | openssl s_client -connect example.com:443 -servername example.com 2>/dev/null | openssl x509 -noout -subject
Ensure the CN or SAN entries contain example.com.
- Update the client trust store
sudo update-ca-certificates # Debian/Ubuntu
sudo update-ca-trust force-enable && sudo update-ca-trust extract # RHEL/CentOS
- Force a compatible TLS version (useful for legacy servers)
curl --tlsv1.2 https://example.com
- Check cipher suite compatibility
openssl ciphers -v 'ALL:@SECLEVEL=1'
Automate the Fix with a Pre‑configured Script
You can run a ready‑made script that applies the above checks and patches common mis‑configurations. Download the pre‑configured script here.
Additional Resources
- Get the complete patch tool for automated remediation in CI/CD pipelines.
- Access the full repository fix to integrate directly into your infrastructure as code.
Conclusion
By systematically verifying the certificate chain, hostname, trust store, TLS version, and cipher suites, you can eliminate most handshake failures. Incorporate the provided script into your deployment workflow to keep environments healthy and secure.
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