Virtual Machine Network Isolated With Zeroed MAC Address After VM level Backup/Snapshot Restore

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• Following a backup and snapshot restore operation, a virtual machine is completely isolated from the network.
• Running the net-stats -l command on the ESXi host indicates the virtual machine is reporting 00:00:00:00:00:00 for its MAC address.

• The esxtop network view demonstrates the virtual machine is not mapped to an uplink, displaying as "void" in the output.

• The vSphere Client UI confirms a valid MAC address is still actively assigned to the virtual machine.
• The issue persists even when the virtual machine is migrated to a different host via vMotion.
• Adding new virtual network interface cards (vNICs) to the virtual machine results in identical symptoms.
• Newly deployed virtual machines on the same host and port group function normally.

Cause

The Guest Operating System (OS) networking stack is corrupted or the interface is administratively disabled internally, preventing the virtual network adapter from initializing and reporting its MAC address to the ESXi hypervisor.

Resolution

1. Obtain or reset the local administrator or root password for the affected virtual machine.
2. Log in to the virtual machine directly using the vSphere Client Web Console or VMware Remote Console (VMRC).
3. Inspect the Guest OS network configuration and manually re-enable or repair the network adapter interface.
4. Verify the adapter initializes correctly and net-stats -l on the ESXi host updates to reflect the assigned MAC address.
5. If the Guest OS networking stack is permanently unrecoverable, restore the virtual machine from a known-good backup taken prior to the initial restore event, or deploy a new virtual machine instance.

Additional Information

net-stats on ESXi shows VM's MAC address as 00:00:00:00:00:00

VM's network connection state shows "Link Down" on the switchport portgroup