vCenter Server inaccessible after ESXi host motherboard replacement

Products

• VMware vCenter Server

Issue/Introduction

• Access to the vCenter Server Management Interface (VAMI) or vSphere Client fails following a hardware lifecycle event on the underlying ESXi host.
• This typically occurs when a motherboard is replaced, causing a mismatch in virtual-to-physical network mappings
• As shown in the image below, the default gateway value is 'Not Set' on the vCenter

Environment

• VMware vCenter Server 7.x
• VMware vCenter Server 8.x
• VMware vCenter Server 9.x

Cause

A physical hardware identifier change (motherboard replacement) can lead to the loss of Distributed Switch (vDS) port state persistence. The VCSA guest OS loses its carrier link, causing the runtime network stack to drop the default gateway.

Resolution

To restore network connectivity, you must bypass the Distributed Switch states by using a temporary Standard Switch.

1.  Deploy a Temporary vSphere Standard Switch (VSS)
   1. Log in to the ESXi host directly where the vCenter VM resides using the Host Client.
   2. Create a temporary vSphere Standard Switch (VSS).
   3. Assign an available, correctly trunked physical uplink to this switch.
   4. Create a Standard Port Group on this switch and assign the correct management VLAN ID (e.g., ####).
2.  Reassign the vCenter Network Adapter
   1. Edit the vCenter VM settings.
   2. Reassign the network adapter (`eth0`) from the Distributed Port Group to the temporary Standard Port Group you just created.
   3. Verify that you can now access the VAMI and the DCUI via the network.
3.  Remediate the Distributed Switch
   1. Log in to the vSphere Client once access is restored.
   2. Navigate to your Distributed Switch settings.
   3. Create a new, dedicated Distributed Port Group for vCenter management traffic and ensure you apply the correct VLAN policies.
   4. Migrate the vCenter VM network adapter from the temporary Standard Switch port group back to the new Distributed Switch Port Group.

Additional Information

The vCenter server fails to connect to its default gateway
Configuring Standard vSwitch (vSS) or virtual Distributed Switch (vDS) from the command line in ESXi