NSX Host Preparation or Reconnection fails due to Duplicate IP Address Conflict

Products

• VMware NSX

Issue/Introduction

When attempting to reconnect a failed host or prepare a new Transport Node in NSX, the operation fails. The NSX Manager UI or logs may report the following errors:

• Error: Credentials for host need to be specified. (Error code: 26208)

• 26210: Node <Node-ID> with same ip <IP-Address> already exists. Check the state of existing transport node.

Syslog Error (nsx-manager /var/log/proton/nsxapi.log):

• desiredStateErrorMessage = 26210: Node <Node-ID>... with same ip 192.##.##.## already exists. Check the state of existing transport node. If it is a failure in deletion then use force option to delete previous transport node and retry the operation.

Environment

NSX 4.x

Cause

This issue is triggered by a duplicate IP address on the management network. When another device shares the same IP as the ESXi host, it creates an ARP (Address Resolution Protocol) conflict. 

Resolution

 

1. Identify the conflict by checking the ESXi host CLI /var/log/vobd.log. for duplicate IP triggers.

2. Look for an entry such as: [vob.net.ip.duplicate] Duplicate IP address detected for 10.10.##.## on interface vmk#, current owner being 00:50:56:##:##:##.

3. Use vSphere Client to search for the specific MAC address found in the log to identify the conflicting VM, host, or interface.

4. Resolve the IP conflict on the network to ensure the Management IP is unique to the intended ESXi host.