Python - Determine if ip is proxy or not

Is there any way how to find out, if ip address comming to the server is proxy in Python?

I tried to scan most common ports, but i don't want to ban all ips with open 80 port, because it don't have to be proxy.

Is there any开发者_运维百科 way how to do it in Python? I would prefere it before using some external/paid services.

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If it's a HTTP traffic, you can scan for headers like X-Forwarded-For.

But whatever you do it will always be only a heuristic.