Unable to ping a virtual machine (VM) after reverting a snapshot.

Products

• VMware vCenter Server

Issue/Introduction

• After reverting to an older snapshot, a VM loses external network connectivity, making it unreachable via pings. Active Directory user logins fail, while local accounts like root or Administrator still function.

Environment

• VMware vCenter Server

Cause

• The network connectivity failure is caused by a change in the Virtual Distributed Switch (vDS) Port Group between the time the snapshot was taken and when it was reverted. When the VM is reverted, it is reconnected to its original, now-outdated vDS Port Group, which no longer provides external network access. This loss of external connectivity also prevents the VM from communicating with the Active Directory server for user authentication.

Resolution

• To restore network connectivity and Active Directory functionality, perform the following steps after reverting the snapshot:

1. 1. Change the assigned port group from the old, incorrect one to the new, current vDS Port Group, referring to document Change the Virtual Machine Network Adapter Configuration
   2. After the VM reconnects to the correct port group, external pings and Active Directory logins will resume functionality.