A white list solution seems rather extreme, although white listing keyhashes might be a bit better, you can even hand out cd-keys and verify in a cryptographicl

A white list solution seems rather extreme, although white listing keyhashes might be a bit better, you can even hand out cd-keys and verify in a cryptographicly secure way server side that the client has the cd-key you've assigned. Using VPN detection techniques on TGE has really helped a great deal without having to jump all the way to white listing.