IBM AIX 7.2 – Common Problem 239 – 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

AIX clock drifts and Kerberos/LDAP authentication fails with clock skew errors.

Environment & Reproduction

Triggered by stopped xntpd, blocked UDP 123, or wrong /etc/ntp.conf servers.

Root Cause Analysis

AIX is not syncing with any upstream NTP source, so the hardware clock drifts.

Quick Triage

Run lssrc -s xntpd and ntpq -p to see peer reachability and offset.

Step-by-Step Diagnosis

Inspect /etc/ntp.conf and confirm UDP 123 outbound is allowed by firewalls.

Solution – Primary Fix

Fix peers in /etc/ntp.conf and restart with stopsrc -s xntpd; startsrc -s xntpd.

Solution – Alternative Approaches

If drift is large, run ntpdate -u server first then start xntpd to keep sync.

Verification & Acceptance Criteria

ntpq -p shows a * peer and offset stays within a few milliseconds.

Rollback Plan

Restore previous /etc/ntp.conf and restart xntpd to revert configuration.

Prevention & Hardening

Use 3-4 stratum-2 peers and monitor with ntpq -p via cron.

Related Errors & Cross-Refs

Related to Kerberos GSSAPI errors and LDAP auth failures on AIX clients.

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 xntpd and ntpq documentation.