The MAC Address on Virtual Machine keeps changing

Products

• VMware NSX

Issue/Introduction

• VM is not accessible over the network
• Disconnecting and reconnecting the VM's NIC card restores network connection briefly
• Ping test to the IP address of the VM still replies when the VM's NIC is disconnected or VM is shut down
• Ping tests to the VM's IP address show that the MAC address on the reply packets does not match the MAC address assigned to the target VM
  
  • Using the arping command  arping -I <interface name> ip-address
  • 
• Traceflow in NSX UI from a source VM that is on the same network as the problematic VM shows that the packet is delivered to the target VM
• Traceflow in NSX UI from a source VM on a different network shows that the packet is delivered to the Edge Uplink

Environment

VMware NSX

VMware vSphere ESXi

Cause

Duplicate IP address - The same IP address has been assigned to another device on the same network

Resolution

• Identify the device that is responding to the pings for the IP address in question when the VM's NIC is disconnected or VM is shut down
• Assign a different IP address to the VM