This week’s problem was to make working Remote Desktop Gateway located behind a NAT. Here’s the lessons learned:

• Issue an SSL certificate with the subject matching public DNS name (FQDN)
• Use the default port 3389/TCP, otherwise SSL certificate’s name won’t match FQDN returning an error:
  

  The computer can’t verify the identity of the RD Gateway.

  or if you put it to current user’s Trusted Root Certification Authorities:

  Your computer can’t connect to the computer because the Remote Desktop Gateway server address requested and the certificate name do not match.

• Publish on the firewall, i.e. make available from outside, HTTPS port 443/TCP. Otherwise connection won’t be established returning another meaningless error:
  

  Your computer can’t connect to the remote computer because the RDG server is temporarily unavailable.

That’s all, folks!