RDS 2019 with Azure App Proxy - lots of lag, and disconnects

Question

I've got an RDS 2019 setup with published desktops and remoteapps, configured to use the Azure AD Application Proxy.

I've followed all steps here- https://learn.microsoft.com/en-us/azure/active-directory/manage-apps/application-proxy-integrate-with-remote-desktop-services
and here https://learn.microsoft.com/en-us/azure/active-directory/manage-apps/application-proxy-add-on-premises-application

I've configured it for pre-auth, but since this wasn't compatible with the Mac RDS clients we switched back to pass-through, so the proxy is just operating as a simple web-proxy and really not doing anything fancy.

Through consistent testing both through the published address that uses the Azure AD Application Proxy and an address that routes right into my network via IP address I've confirmed considerable lag spikes through the proxy that do not exist when going through the direct address. Also users get significantly more short disconnects throughout the day. Also occasionally the RDS Web Access Portal (IIS website) becomes inaccessible through the proxy for a few seconds at a time, whereas these drops do not occur through the direct address (we setup alerts on both to monitor).

I've monitored my organizations bandwidth usage at the times when the lag and disconnects occur (they happen in spikes and the lag can linger for long periods of time but there does not seem to be any consistent pattern to the times or regularity that they occur at) and we are well below our highest traffic at these times (200mbps pipes, with around 80-100 users in RDS we're usually only using between 20-30 mbps)

I'm stumped. I read on an old forum post that the Azure Application Proxy didn't handle UDP properly for RDS, is that the case? I pushed for the proxy in our architecture and have asked for patience in my organization while we worked on this because it's a Microsoft support product and configuration, I'm baffled that I'm not finding more about this anywhere (either the configuration, troubleshooting techniques, or this particular issue).

I have the gateway, connection broker, webserver and licensing components on one server, and around 8 servers operating as Session Hosts with different applications and configurations. All of these servers are filthy rich with resources on high end newish hyper-v servers, and as I said have no issues with performance either inside of my network or outside of it connecting through the direct address, these issues ONLY occur when routing through the Azure AD Application Proxy.

Thanks!

Answer 1

My issue ended up being about connectors installed on machines that were turned off. Apparently as the azure app proxy tried to load balance it would send connections to these turned off machines causing disconnects or lag. Moving my always on connector VM's to their own connector group resolved the issue.

Answer 2

Hi,

According to your description, the issue comes from the Azure AD Application Proxy. It seems there is no much problem with RDS at the moment.

In that case, we will first delete the RDS tag. Appreciate your patience to wait for our Azure expert to investigate the issue for you.

Thanks,
Eleven

Answer 3

Since all of these issues are around RDS experience, and this is about the configuration of an RDS server farm integrating with the App Proxy I do think this is RDS related. At least I was hoping for some other users who followed the Microsoft instructions for RDS configuration with this service to chime in as to whether they had similar problems or if their configurations worked, or an answer to this question "I read on an old forum post that the Azure Application Proxy didn't handle UDP properly for RDS, is that the case". That doesn't seem a likely outcome since this new forum system seems even less trafficked than the old Technet forums.

Either way if and when I don't hear back about this from anyone in relation to the Azure AD Application Proxy (is no one using it?) where should I followup? Is this somethings I should open an azure support ticket for?

Answer 4

Should I just assume that the Azure AD Application Proxy doesn't actually work for anything that requires high throughput and stability? There doesn't seem to be much documentation or really any support on the product as far as I can find.