Random freezes (several minutes) in RDS applications

Question

A customer has stability problems with two applications published over RDS. The employees work the whole day with these applications, and one to three times a day, the applications freeze for 2 to 7 minutes each time. The employees don't get any error message, all open RDS applications just freeze. In addition, the clients (Win10, different versions) have a permanent direct access connection to the internal network.

What we have done and tried so far:

• Added IPv6 addresses to all RDS Servers in the farm, according the Microsoft documentation that exactly describes our environment: https://learn.microsoft.com/en-US/troubleshoot/windows-server/remote/remote-desktop-server-farm-not-available.
• Examined in detail the eventlogs on the clients and on the RDS servers for the exact period when a client has a freeze. There is not one warning or error event logged.
• On some Win10 clients, we set up a "ping -t <RDS Session host>" command running always. While the RDS applications freeze, the connection to the session hosts is not broken, and the Win10 clients always get ping replies from the session host.
• Tried different configuration options for accessing the RDS farm: We have configured direct access so that the RDS farm is reached only externally, and we have also tried a "force tunnel" configuration so that the RDS farm is reached only over the VPN/Direct Access tunnel. In this configuration, the client behavious like it is in the internal corporate network.
• Tried accessing the farm directly when connected to the internal network, and also the opposite, always accessing the RDS farm over the gateway.
• Have deactivated UDP on the gateway.
• The problem is a combination of RDS and direct access, or another VPN connection (we tried Fortigate VPN instead of direct access on a test client). When a client has no VPN connection to the corporate network, the problem does not exist. But the employees need a permanent VPN connection for accessing file server shares.

Have spent sveral days the last few weeks to solve this problem, and we are running out of ideas. Thank you all in advance for any advice.

Franz

Answer 1

Hi,

Thank you for posting your query. According to my research, some people have experienced the similar issue and resolved by turning off UPD on client PC. Maybe you can try this way.

Run Group Policy Editor.
Navigate to Computer Configuration > Administration Templates > Windows Components > Remote Desktop Services > Remote Desktop Connection Client. Set the "Turn Off UDP On Client" setting to Enabled.
GP update and no need to reboot.

Best Regards,
Grace

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Answer 2

Hi, have already deactivated UDP on the gateway. Have deactivated UDP on a test client as well, as you suggested. Unfortunately, this makes no difference. The employee had two "freezes" this afternoon, one of 2 minutes, one of five minutes.

Answer 3

Hi,
Thanks for your reply and detailed information above. As what we've discussed, this issue is beyond my help via forum. It is something related to your VPN and definitely need catching dump to do analysis, then solve this issue. Under this circumstances, it is highly recommended that you should look for more professional help from Microsoft to open a case. Here is the link you can refer to. Our team will help you futher with this issue.
https://support.microsoft.com/en-us/help/4051701/global-customer-service-phone-numbers

Best Regards,
Grace

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