Troubleshooting a Broken Network Adapter in vSphere ESXi

You reboot a VM and 2 hours later you realise there’s no network connectivity on that VM.
You try to open the Network and Sharing Center console but the window just hangs and everything seems to be chugging along very slowly.

I’ve experienced a number of different scenarios where network adapters go AWOL in a VM – usually caused by a guest (Windows Update) or VM hardware update. For the latter it is best practice to update the VMware Tools first before upgrading the hardware version.

Things to Check

  • Check the vmware.log file to see if there’s anything obvious
  • Are you running an ‘enhanced’ network adapter such as VMXNET3? If so, make sure you have VMware Tools installed on the virtual machine and make sure it’s up to date
  • You can rule out the network adapter by using E1000 (which is basically a plug-and-play adapter on machines > Server 2003)
  • Completely remove the network adapter. Reboot the VM. Add the network adapter again and watch to see if Windows detects the hardware. Configure the IP settings and see if it works. If it does, reboot the VM and see if it continues to work (it sounds silly but when I removed and re-added the network adapter it worked but after a reboot it went back to being broken)
  • It the above still hasn’t fixed your problem then you can try rebuilding the TCP/IP stack in Windows by opening an elevated command prompt window and typing the following:

netsh int ip reset

Hope that helps!