🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026
Affected versions: SUSE Linux Enterprise Server 15

📖 ~1 min read

Table of contents
  1. Symptom & Impact
  2. Environment & Reproduction
  3. Root Cause Analysis
  4. Quick Triage
  5. Step-by-Step Diagnosis
  6. Solution – Primary Fix
  7. Solution – Alternative Approaches
  8. Verification & Acceptance Criteria
  9. Rollback Plan
  10. Prevention & Hardening
  11. Related Errors & Cross-Refs
  12. References & Further Reading

Symptom & Impact

Browsers display certificate errors when connecting through HAProxy frontends.

Environment & Reproduction

Seen after certificate rotation or addition of new SNI hosts.

Root Cause Analysis

PEM bundles in `crt-list` are out of order or include a default certificate that overrides SNI.

Quick Triage

Inspect HAProxy stats and `haproxy -c -f /etc/haproxy/haproxy.cfg` output.

Step-by-Step Diagnosis

Use `openssl s_client -servername host -connect …` to confirm which cert is served.

Illustrative mockup for sles-15 — haproxy_cert-mismatch_terminal
Terminal diagnostics for HAProxy on SLES 15 serves wrong TLS certificate — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Rebuild the crt-list, ensure correct SNI mapping, and reload HAProxy gracefully.

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Illustrative mockup for sles-15 — haproxy_cert-mismatch_logs
Logs and evidence for HAProxy on SLES 15 serves wrong TLS certificate — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Use the `ssl-default-bind-curves` and modern cipher suite list to harden.

Verification & Acceptance Criteria

All SNI hosts present the correct certificate and chain.

Rollback Plan

Roll back to the previous crt-list backup if a misconfigured cert is deployed.

Prevention & Hardening

Automate certificate rotation with Salt or Cert-Manager.

Pairs with `unable to load SSL certificate` warnings on reload.

Related tutorial: View the step-by-step tutorial for sles-15.

View all sles-15 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

SUSE HAProxy configuration and TLS reference docs.

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