Monday, January 18, 2016

VM not accessible/lost network connectivity after reboot

This past week as part some activity we powered off some Virtual Machines and after some time when powered on those VMs again, I was surprised when the network would not come up for two VMs. I tried to ping them but VMs were not reachable so I logged-in on one of the virtual machine via VM console to check the IP configuration etc and found Network Card was showing limited connectivity (yellow sign on NIC icon) however the IP information was correct, then tried to ping from inside the VM without success. I also the rebooted the VMs again but that didn’t fix the connectivity issue.

I did remember few months back we had faced a similar issue however at that time default gateway was not turned on and ipconfig was showing an APIPA address like 169.254.x.x. To fix that issue we had to reconnect the VM network card so tried the same here too and it worked.

To fix the issue what you need to do is, Select the affected VM and go to Edit VM settings => select the vNIC adaptor =>Deselect Connected => Now click OK to apply the setting



Now Navigate again to the Edit VM Settings => select the vNIC adaptor =>Select Connected => And click OK to apply the setting.
Once settings applied, VM came back to network again.

On another VM just to test if a cold reboot would work here, I powered off the VM and once it powered off, powered it on again and voila VM was accessible again. 

Thus we can fix this issue either by a cold reboot  or by reconnecting the virtual network card.

Update: Today I came across the same issue again, this time it was a MS Server 2012 R2 OS VM and a cold reboot didn't fix the issue, one more thing sometime in order to fix the issue, you may need to repeat the vNIC disconnect process.

Update2_25/02/2016: Sometime the above wouldn't work at all, then what you can do is: login to the affected server via VM console => Go to Network card properties and disable, re-enable the network card from inside the OS and hopefully server would come back to network again.
The other thing you can do is Change the IP assignment setting from Static to Dynamic, it would pick an IP from APIPA, then change it back to Static and it should work now.

Note: For further detail about the issue, you may refer to the related VMware KB#2012646.

That’s it... :)


9 comments:

  1. I got this issue after IP conflict and did the same thing.

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  2. Most of the time, Disable / Enable the NIC from inside OS fix the issue.

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  3. https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2012646

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    1. This kb article is already listed in this post...anyways thanks

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  4. I am also having the same problem. Did you ever find the cause and possibly a solution?

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    1. AFAIK all possible solutions are already listed here, except one related to reg edit...this issue is kind of we face once in months and not permanent...this is whats VMware thinks causing the issue, kb#2012646....This issue occurs because the IP address registry values are incorrectly overwritten by a newly added IP address, instead of the whole list of IP addresses.

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  5. I am having the same problem. Have you found out what's causing the problem? Or any possible solution?

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    1. this is whats VMware thinks causing the issue, kb#2012646....This issue occurs because the IP address registry values are incorrectly overwritten by a newly added IP address, instead of the whole list of IP addresses.

      Delete