Just a suggestion & mileage may vary...
If you have another PC available on the same network as the client machine [surely everyone has a couple of old spares floating around/hidden in the loft?!] - then you could maybe try running a tool such as PingPlotter & point it at the GPL server address as indicated in iGOR race list. There is a free version available at
https://www.pingplotter.com/products/free.html.
Granted, this is not sending 'proper' race traffic, but may give an indication of potential issues & whether it's a local network or somewhere in the middle.
If the GPL server is not replying to ping requests [most likely if the firewall feature set on the remote side is doing its job too well & silently dropping them] then the endpoint will show as non-responsive/100% loss, but the details from the previous hop may still give an indication of overall health.
Cheers,
Dave.