Unique identifying information in HTTP requests?

Question

From the perspective of a wireless router on a wall in a coffee shop, can my computer be uniquely identified via an HTTP request? I think it get's my MAC adress doesn't it?

Next question, from the perspective of a remote server that I send an HTTP request to, can I be uniquely identified? In this case, the server doesn't get my MAC address, but someone else's that is past me, right? What other information could make my HTTP request uniquely identifiable? The IP address doesn't help either, because that would just narrow me down to the coffee shop I'm setting in, right? And I could always move to a different router. I suppose cookies would work here, but we can't guarantee that people won't flush their cookies. How close can we get to unique identifiability? What strategies can be used.

Answer 1

Your best option are HTTP Headers, you can take at this list for some headers already in the wild. I don't know what you are trying to achieve, but I suppose you want to create an identifier for every user. So you have two options, implement this on router or gateway or on the client side.