Pre-authentication failure with DVLS via Azure App proxy renders RDM unresponsive

Hello Joe,

Thank you for the detailed report.

Remote Desktop Manager should not become unresponsive when the Azure pre-authentication flow fails, so we will need a bit more information to isolate whether this is configuration-related or a client-side hang.
Please check the following:

• Test bypassing Azure App Proxy (connect directly to the DVLS URL on the internal network). Let us know if the hang only happens when going through the App Proxy.
• Confirm the published external URL is not at the root. The Azure pre-auth setup requires DVLS to be under a suffix path (for example, https://myserver.com/dvls, not https://myserver.com).

If the issue still occurs, please provide DVLS logs around the time of the hang:

• DVLS Data Source Logs (Reports – Data Source Logs) after enabling debug logging.
• If you can enable it briefly, DVLS HTTP logs (DPS_Main.log) to see the request/redirect/auth sequence during the failure.

Documentation:

• Azure pre-authentication to a Devolutions Server data source in Remote Desktop Manager
• https://docs.devolutions.net/rdm/kb/how-to-articles/azure-pre-authentication-dvls-rdm/
• View Devolutions Server logs
• https://docs.devolutions.net/server/web-interface/administration/logs/view-server-datasource-logs/
• Enable Devolutions Server HTTP logs
• https://docs.devolutions.net/server/kb/how-to-articles/enable-http-logs/
• Reverse proxy configuration (external URL settings behind a proxy)
• https://docs.devolutions.net/server/kb/how-to-articles/devolutions-server-docker-deployment/advanced-docker-configuration/#reverse-proxy-configuration

Best regards,

Hi Patrick,

Thanks for assisting with this.

I can reproduce the issue easily by switching to an Azure App Proxy data source, then clicking cancel on 'waiting for pre-authentication' dialog before doing any actual authentication in the browser. After this, its not possible to click anything in RDM.

As this is occurring before authentication succeeds, and the client connects to server, there is unlikely to be anything logged on DVLS.

Issue does not occur when accessing DVLS directly, and URL has /dvls.

If cancel button is not clicked, and authentication is successful, then RDM connects successfully. The problem is that if authentication fails for whatever reason, RDM locks up.

Are you able to reproduce on your end?

Joe

Hello Joe,

Thank you for this feedback.

Yes, after cancelling the preauth, RDM is no longer responsive.
I will open a ticket for this issue.

Best regards,