VM experiencing loss of network connectivity on vSphere Distributed Switch (VDS)

Products

• VMware vSphere ESXi

Issue/Introduction

A Virtual Machine (VM) connected to a port group on a vSphere Distributed Switch (VDS) and specific VLAN experiences complete network connectivity loss and is unable to ping its default gateway. Other VMs located on the same port group and residing on the same ESXi host can successfully ping the default gateway.

Packet captures reveal ARP packets successfully reaching the Distributed Virtual Port (DV port) ID, but they fail to traverse or reach the ESXi host physical uplink. Inspection of the DV port statistics shows the droppedTx packet counter continuously incrementing.

Environment

VMware ESXi

Cause

The VM network connectivity loss is caused by a configuration database synchronization failure, where the Distributed Virtual Switch (VDS) port state is out of sync with the vCenter Server database. This database discrepancy prevents proper packet forwarding, resulting in an increasing count of transmit drops (droppedTx) at the DV port layer.

Resolution

 

• Refer to KB 317923: ESXi hosts showing out of sync with Distributed Switch for detailed steps to resynchronize the Distributed Virtual Switch (VDS) database configuration across affected ESXi hosts.

• As a temporary workaround to restore immediate VM connectivity, perform the following steps:

  1. In the vSphere Client, navigate to the affected Virtual Machine.

  2. Select Actions > Edit Settings.

  3. Locate the Network Adapter connected to the affected port group and change its Port ID to assign it an available port ID.