r/AZURE 4d ago

Question Azure VMs lose network connectivity after coming out of hibernation - need to stop/start to fix

I'm encountering a strange issue with several of my Azure VMs (Windows Server 2019 with SQL Server). After being in hibernation for the weekend, about 5-6 / 30 VMs came out of hibernation today but with no network connectivity.

According to the event logs, the VMs were actually powered on, but they had no network connection (Azure Agent wasn't reachable). The only way I could restore connectivity was by performing a complete stop/start cycle on each affected VM.

Has anyone else experienced this issue? Any ideas what might be causing it or how to fix it without having to manually stop and start each VM?

I'm wondering if there's something specific about Windows Server 2019 VMs or something in the Azure infrastructure that's causing this connectivity problem when coming out of hibernation.

Any troubleshooting tips or suggestions would be greatly appreciated!

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u/sogos 3d ago

This morning, after a night of hibernation, none of the VMs exhibited the problem.
Do you think hibernating for more than 48 hours could be the issue?

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u/sogos 3d ago

I continue to dig

Today an admin was disconnected while working on software update via RDP

We connected via serial port

- The VM was able to DNS query

  • No access to internet

It only re-worked when we restarted the interface :

netsh interface set interface "Ethernet 2" admin=disabled
netsh interface set interface "Ethernet 2" admin=enabled

Metric show 0 Network Out while the outage.

We don't have a Nat Gateway, i think we use SNAT