Detect VPN via C# or api

Question

I have a win app and I need to be able to help troubleshoot VPN issues that might be blocking my app. First I need to be able to tell if they have VPN or are connected to VP

Answer 1

Look for the presence of another style of adapters besides Ethernet, list all of the network connections and their types, unless they have a 56.6k modem, if they have a PPP style adapter, it would strongly indicate a VPN tunnel.