Resolving virtual machine IP address conflict issues

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

Most Microsoft Windows versions report duplicate IP address via pop-up error messages:

• The system has detected a conflict for IP address
• There is an IP address conflict with another system on the network
• The static IP address that was just configured is already in use on the network. Please reconfigure a different IP address

cannot-connect-vm cannot-manage-vm connect-vm manage-vm

Environment

VMware ESX Server 3.5.x
VMware ESX Server 3.0.x
VMware ESXi 4.0.x Installable
VMware ESX 4.1.x
VMware ESXi 4.1.x Installable
VMware ESXi 3.5.x Installable
VMware ESXi 4.1.x Embedded
VMware VirtualCenter 2.0.x
VMware vCenter Server 4.0.x
VMware ESXi 3.5.x Embedded
VMware VirtualCenter 2.5.x
VMware ESXi 4.0.x Embedded
VMware vCenter Server 4.1.x
VMware ESX 4.0.x

Resolution

Resolving IP address conflicts

To resolve IP address conflicts:

1. For network environments with statically assigned IP addresses, ensure each local host is configured with a unique IP address.
   
   If your computer has a dynamically assigned address, releasing and renewing its IP address can workaround IP address conflicts.
   
   
2. Clear the ARP table of the LAN switch

3. Assign a new IP address that has never been used if that option is available. First ping test the IP address before assigning it to confirm its availability.

Resolving TCP/IP stack issues on the virtual machine

To resolve TCP/IP stack issues on the virtual machine:

1. Remove and reinstall your virtual network adapter driver.
2. Verify, using the vSphere/ VI Client, that the ethernet adapter is connected and powered:
   
   
   1. Enable and disable the NIC and ping test.
   2. Uninstall VMware Tools and ping test.
   3. Connect to host using the vSphere/ VI Client.
   4. Turn off the virtual machine.
   5. Remove the ethernet adapter.
   6. Turn on the virtual machine. TCP/IP is not loaded.
   7. Turn off the virtual machine again.
   8. Add the ethernet adapter – at this point either auto assign a MAC or manually assign one.
   9. Assign a different IP address to eliminate the possibility of duplicate IP and do a ping test.
   10. Reinstall VMware Tools and do a ping test.

For related information, see Verifying virtual network adapter is present and connected to the virtual machine (1003786).

If there is a problems with assigning the IP address to the Virtual network adapter please see the following article Networking Error, IP Address Already Assigned to Another Adapter (1179).

Additional Information

Como solucionar problemas de conflito de endereço IP em máquinas virtuais
Resolución de problemas de conflictos de direcciones IP de máquinas virtuales
解决虚拟机 IP 地址冲突问题
仮想マシンの IP アドレスの競合問題を解決する