Virtual Machine: Failure to connect via RDP or SSH — Network connectivity issue

Question

Virtual Machine: Failure to connect via RDP or SSH — Network connectivity issue

Dhaval-9536 0

Problem description

I am unable to connect to my Azure Virtual Machine running Windows via RDP or SSH. The VM does not respond to ping requests and cannot be reached through the specified ports. The connection attempt is made to the VM's private IP, and I have confirmed that there is no public IP associated with this access path. The issue started around 2026-11-04 18:30 UTC, with no recent configuration changes reported.

Environment

Azure Virtual Machine running Windows, failure to connect using RDP or SSH port, located in a region not specified in the case information

What I've already tried

I have reviewed the available case details and diagnostic information. The VM is reachable through Serial Console, and from inside the VM, it can ping other VMs on the same subnet. No configuration changes have been reported prior to the issue starting.

Current status

I am seeking assistance to diagnose and resolve the connectivity issue, specifically to understand whether the problem is within the VM's network configuration, firewall, or Azure network settings.

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1 answer

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Answer 1

Hi @Dhaval-9536

The Serial Console detail helps a lot. The VM is running and can reach its own subnet, so the break is either inside Windows (firewall or the RDP service) or on the path from your client to that private IP. One note first: ping isn't a reliable test, because Windows Firewall blocks ICMP by default, so "no ping" on its own doesn't mean the network is down.

Inside the VM (via Serial Console, open a CMD channel):

Run netsh advfirewall show currentprofile. If the network has flipped to the Public profile, inbound RDP can be blocked even though nothing was changed on purpose. Run netsh advfirewall firewall set rule group="remote desktop" new enable=yes to re-enable the RDP rules.
Run netstat -ano | findstr 3389 to confirm RDP is listening. If nothing shows, restart the service with net stop termservice then net start termservice.
Run ipconfig /all and check that the IP, gateway and DNS still match the NIC settings in the portal.

On the Azure network side (portal):

Use Network Watcher > IP flow verify with your client's IP as the source and the VM's private IP on port 3389. It names the exact NSG rule that allows or denies the traffic.
Check Effective routes on the VM's NIC. A new route through a firewall or NVA, or a change on the VPN/ExpressRoute side, would explain a sudden break without any change on the VM.

Where does the connection come from: another VM in Azure, or your office over VPN/ExpressRoute?

If RDP works again after this, please consider accepting it as the answer. If IP flow verify shows "Allowed" and it still fails, let me know and I'll be happy to keep helping.

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