This question already has an answer here:
I understand that if I enable geolocation option in Firefox, then Netflix can learn where I am, and by comparing my actual location with my reported location, Netflix can deduce that I am behind a VPN.
If you consent, Firefox gathers information about nearby wireless access points and your computer’s IP address. Then Firefox sends this information to the default geolocation service provider.
But let's say if I disable that, will Netflix ( or other webservices) still be able to know that I am hiding behind a VPN? If yes, how?