Hi I'm creating a game and I would like to be able to tell if a user is using a proxy. If they are than it basically puts a flag on their account. I can make it do the flag and all but I'm not exactly sure how to tell if a user is using a proxy. I've seen you can use headers but I'm not exactly sure which to look for and how you would check if a user "has" a header (besides the normal http_referrer and what not).

Any help is greatly appreciated.