RHEL 9 OpenSSH key authentication denied unexpectedly

📖 ~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 login fails while password login may still work.

Environment & Reproduction

sshd reports key refused, bad ownership, or no matching key type allowed.

Root Cause Analysis

Improper file modes, wrong authorized_keys path, unsupported key algorithms, or SELinux labels.

Quick Triage

Check ~/.ssh permissions, sshd_config directives, and client key algorithm compatibility.

Step-by-Step Diagnosis

Set user home, .ssh, and authorized_keys permissions to OpenSSH-safe values.

Solution – Primary Fix

Use journalctl -u sshd and client -vvv output to isolate exact rejection cause.

Solution – Alternative Approaches

Run restorecon -Rv on user home SSH paths when labels are inconsistent.

Verification & Acceptance Criteria

Ensure enterprise crypto policy and sshd accepted key types match generated keys.

Rollback Plan

After configuration edits, run systemctl reload sshd and retest.

Prevention & Hardening

Keep a console or break-glass admin account available during key auth changes.

Related Errors & Cross-Refs

Use configuration management to enforce correct key permissions and options.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Confirm key login success from trusted jump hosts and audit log cleanliness.