🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026
Affected versions: CentOS Stream 9

📖 ~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

Public-key auth fails with `Permission denied (publickey)`.

Environment & Reproduction

After moving home dirs or restoring backups.

Root Cause Analysis

Wrong perms on `~/.ssh`, `authorized_keys`, or SELinux labels.

Quick Triage

Run `ssh -vvv user@host` to see the auth steps.

Step-by-Step Diagnosis

Inspect `/var/log/secure` for sshd messages.

Illustrative mockup for centos-stream-9 — terminal_or_shell
SSH key-based auth denied diagnostics in terminal — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Set perms: `chmod 700 ~/.ssh && chmod 600 ~/.ssh/authorized_keys`.

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Illustrative mockup for centos-stream-9 — logs_or_journal
journal and log evidence for SSH key-based auth denied — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Run `restorecon -Rv ~/.ssh` to fix SELinux contexts.

Verification & Acceptance Criteria

Login by key succeeds, password fallback is no longer needed.

Rollback Plan

Re-enable password auth temporarily if locked out via console.

Prevention & Hardening

Use SSH certificates or centralized auth for fleets.

Linked to PAM, sssd, and home directory mount issues.

Related tutorial: View the step-by-step tutorial for centos-stream-9.

View all centos-stream-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

OpenSSH server documentation and SELinux ssh booleans.

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