Web crawler-Does PHP identify the client's real IP is a pseudo proposition at all?

At present, the server anti-crawler, limit the number of user requests, are the use of restrictions on client IP policies, online about PHP recognition client IP is nothing more than crawl the following three kinds:
Http_client_ip
Http_x_forwarded_for
Remote_addr
And the first two can be arbitrary random forgery, the third can also use proxy IP spoofing server ... Does PHP really not recognize the real IP of the client? There's no way to crawl a spider?

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At present, the server anti-crawler, limit the number of user requests, are the use of restrictions on client IP policies, online about PHP recognition client IP is nothing more than crawl the following three kinds:
Http_client_ip
Http_x_forwarded_for
Remote_addr
And the first two can be arbitrary random forgery, the third can also use proxy IP spoofing server ... Does PHP really not recognize the real IP of the client? There's no way to crawl a spider?

In this words, it's like Java can recognize it.

There should be no way to identify fake IPs.

I didn't find out which one was fully identified.

Make a proxy server before the application server, and then use Http_x_forwarded_for to compare the points.
As for the "proxy server", it seems to be really a problem of no solution.

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