go - Correct way of getting Client's IP Addresses from http.Request

Question

What's the correct way to get all client's IP Addresses from http.Request? In PHP there are a lot of variables that I should check. Is it the same on Go?

One that I found is:

req.RemoteAddr

And is the request case sensitive? for example x-forwarded-for is the same as X-Forwarded-For and X-FORWARDED-FOR? (from req.Header.Get("X-FORWARDED-FOR"))

Answer 1

Waitting for answers