Virtual machine lost network connectivity due to duplicate IP addresses
Article ID: 404707
Updated On:
Products
VMware vSphere ESXi
Issue/Introduction
• Virtual machine is unable to ping its gateway IP.
• Command ipconfig/all shows duplicate ip/same IP on multiple guestOS.
• To Isolate/Identify the MAC of the machine with the duplicate, with the mac information you can check on the host/s via "net-stats -l" command or via the switch CAM/MAC table to which switchport matches.
• When doing a ping or test connectivity to the VM, we observe that the source MAC address on the reply packets does not match the MAC address assigned to the target VM. Instead, the source MAC on the reply packets matches that of another VM (the one with the duplicated IP).
• Command ipconfig/all shows duplicate ip/same IP on multiple guestOS.
• To Isolate/Identify the MAC of the machine with the duplicate, with the mac information you can check on the host/s via "net-stats -l" command or via the switch CAM/MAC table to which switchport matches.
• When doing a ping or test connectivity to the VM, we observe that the source MAC address on the reply packets does not match the MAC address assigned to the target VM. Instead, the source MAC on the reply packets matches that of another VM (the one with the duplicated IP).
Environment
VMware vSphere ESXi
VMware vSphere vCenter
Cause
The same IP address has been assigned to two virtual machines in the same network
Resolution
• Change the IP of the duplicate VM to another one not overlapping.
• Configured the VM with the duplicate IP to use DHCP if avaiable
• Remove the vnic adapter for the VM
Feedback
Yes
No
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