IBM AIX 7.2 – Common Problem 238 – Diagnosis and Fix

📖 ~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

ssh login fails with Permission denied (publickey) despite a valid key pair.

Environment & Reproduction

Hit after copying keys with wrong permissions or HOMEDIR on a non-standard filesystem.

Root Cause Analysis

sshd refuses keys when ~/.ssh or authorized_keys are group/world writable.

Quick Triage

Check perms with ls -la ~/.ssh and tail /var/adm/messages or sshd log.

Step-by-Step Diagnosis

Run sshd -ddd -p 2222 in foreground to capture the rejection reason.

Solution – Primary Fix

Fix with chmod 700 ~/.ssh && chmod 600 ~/.ssh/authorized_keys && chown $USER:staff.

Solution – Alternative Approaches

If StrictModes is enforced, also ensure the home dir is not group writable.

Verification & Acceptance Criteria

ssh connects without password and sshd log shows Accepted publickey.

Rollback Plan

Restore previous authorized_keys backup and revert chmod if access broke.

Prevention & Hardening

Distribute keys via Ansible and audit perms with find ~/.ssh -perm /go+w.

Related Errors & Cross-Refs

Related to PAM failures, login.cfg restrictions, and LDAP user lookup issues.

Related tutorial: View the step-by-step tutorial for aix-7.2.

View all aix-7.2 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

IBM AIX 7.2 OpenSSH and PAM administration documentation.