Getting a DNS error when trying to connect my Azure VM through Bastion

Hi,

the error dns_probe_finished_nxdomain means the bastion host name cannot be resolved in dns. In your screenshot the browser is trying to reach something like bst-…bastion.azure.com and dns is returning that the name does not exist.

So what I'm thinking, this usually happens for a few reasons. The Bastion resource was deleted or is still being provisioned. The public dns record has not propagated yet. There is a dns filter or proxy on the corporate network blocking resolution. Or the Bastion host is in a different subscription or region than expected.

at Azure portal check the Bastion resource state. It must be in succeeded state and not updating or deleting, then open it from the VM blade using the Connect and Bastion button instead of using a bookmarked URL so that a fresh session URL is generated.

If it still fails try from another network such as a mobile hotspot to rule out corporate dns filtering. You can also run nslookup for the bastion.azure.com hostname and see whether it resolves to an ip address.

If dns does not resolve at all then the issue is outside the VM and outside Bastion itself. It is a dns resolution problem between your browser and Azure public dns...

rgds,

Alex

Hello @ Michael Swierzbinski

Thanks for reaching out to Microsoft Q&A.

I have reproduced the issue and i was able to connect the VM through Bastian. Please find the below screenshot.

The issue could be caused by several factors.

1. Please try to connect through Bastian directly from portal.
2. Please check whether the RDP port is allowed through the local firewall.
3. Also, verify that the NSG inbound and outbound rules are configured correctly.
4. If you are trying to access the VM from an on-premises network, please try connecting from a different network (such as a mobile hotspot or home Wi-Fi).
5. Check the VM status by navigating to Boot diagnostics.

1. Additionally, you can run the Connection Troubleshoot tool in the Azure portal under VM > Help + Support to further diagnose the issue. Source is Azure VM and destination is your local VM IP address

If the above steps didn't resolve your issue, please check the private message and share us the requested details and share the connection troubleshoot result to investigate further

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