Azure Virtual Desktop RDP Shortpath and NAT Gateway not working

Question

Hey there,

We have a Azure Virtual Desktop (AVD) environment where we use a outbound NAT Gateway in Azure to ensure all of our sessionhosts are using the same outbound IP addresses. We want to use RDP Shortpath, but we don't get it to work in combination with the NAT Gateway.

I have tested to put a specific host outside of our subnet with has a NAT Gateway attached, there the MSRDC client says it has been using UDP but when placing the sessionhost back behind the NAT Gateway, it wont work.

I have already ran the following script: https://learn.microsoft.com/en-us/azure/virtual-desktop/troubleshoot-rdp-shortpath
And it returns the following:

Checking DNS service ... OK
Checking STUN on server 20.202.68.48:3478 ... OK
Checking STUN on server 13.107.17.41:3478 ... OK
STUN works, but your NAT type appears to be 'symmetric'.
Shortpath for public networks is very unlikely to work on this host.
See https://go.microsoft.com/fwlink/?linkid=2204021 for more information.

Is there anyone who knows why this isn't working?

Answer 1

Hello @JustinVer,

Thank you for reaching out to the Microsoft Q&A platform. Happy to answer your question.
It is failing because short path doesn't work with NAT gateway. It is documented here https://learn.microsoft.com/en-us/azure/virtual-desktop/rdp-shortpath?tabs=public-networks#network-configuration

Hope this helps.
Please accept as answer and upvote if the above information is helpful for the benefit of the community.

Answer 2

RDP Shortpath for public networks (UDP) will work with Nat Gateway. You will need to go into the properties of the Host Pool and set the switch next to "Validation Environment" -> Yes.