IBM AIX 7.2 – Common Problem 018 – 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

sendmail queue grows and mailq shows deferred messages.

Environment & Reproduction

IBM AIX 7.2 LPAR exhibiting sendmail / SMTP queue issues under standard PowerVM workloads.

mailq | head
lssrc -s sendmail

Root Cause Analysis

Outbound MX unreachable or sendmail run-as user lacks /var permissions.

Quick Triage

Confirm scope with errpt, recent changes, and subsystem state via lssrc.

errpt | grep mail
ls -l /var/spool/mqueue

Step-by-Step Diagnosis

Inspect mqueue, queue runners, and DNS MX lookup.

sendmail -bp
host -t MX example.com

Solution – Primary Fix

Force a queue run after fixing connectivity.

sendmail -q -v
refresh -s sendmail

Solution – Alternative Approaches

Relay through corporate smarthost defined in sendmail.cf.

Verification & Acceptance Criteria

Confirm subsystem returns to RUNNING state and errpt shows no new entries.

mailq
lssrc -s sendmail

Rollback Plan

Restore prior configuration from mksysb or alt_disk_install clone if the fix regresses.

stopsrc -s sendmail  # rollback config from backup

Prevention & Hardening

Encode the fix in NIM customisation scripts and monitor via topas/nmon.

smit sendmail  # rotate logs and define smarthost

Related Errors & Cross-Refs

errpt mailer timeouts; DNS resolver 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

AIX sendmail Administration