RTP Redirect by Country - Does it Use Inferred Country/IP Lookup?

Hello,

We're looking to redirect a single landing page based on the country the visitor arrives from. I'm curious to know if the location.country condition listed here works off of inferred IP (which I understand is an IP lookup) or if the visitor must be known and have delcared their country by providing that info in a form.

We're hoping it's the former and if the RTP redirect does not work in this way, we're definitetly interested in hearing alternative solutions.

Thanks!