IBM AIX 7.3 – Common Problem 210 – 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

Connectivity drops intermittently and errpt logs duplicate IP address detected.

Environment & Reproduction

Two hosts or interfaces share the same IP after LPAR clone or DR test.

errpt | head
arp -an
netstat -in

Root Cause Analysis

Another node on the LAN is using the configured IP, causing ARP conflicts.

Quick Triage

Confirm the duplicate using arp and external pings.

arp -an
ping -c1 ip_address
entstat -d en0 | head

Step-by-Step Diagnosis

Compare MAC addresses in ARP cache against expected adapter.

arp -an | head
entstat -d en0 | head
netstat -in

Solution – Primary Fix

Re-IP the offending host or reconfigure the duplicated interface and refresh ARP.

chdev -l en0 -a netaddr=newip -a state=up
arp -d ip_address
ping -c2 gateway

Solution – Alternative Approaches

Move the LPAR to a dedicated VLAN until duplicate IP is corrected on the peer.

Verification & Acceptance Criteria

errpt no longer shows duplicate IP entries and ping is stable.

errpt | head
netstat -in
ping -c3 peer

Rollback Plan

Revert to the original IP after the conflict is resolved on the peer host.

chdev -l en0 -a netaddr=origip
ifconfig en0 up
arp -an

Prevention & Hardening

Maintain an IPAM, use DHCP reservations, and test clones with cleared MAC/IP.

Related Errors & Cross-Refs

Related to NFS hangs, sshd login failures, and gratuitous ARP loops.

Related tutorial: View the step-by-step tutorial for aix-7.3.

View all aix-7.3 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

IBM AIX 7.3 TCP/IP configuration guide.