PHP obtains the proxy server ip address used by the user, that is, the real ip address.

PHP gets the proxy server ip used by the user, that is, the real ip from the http://www.phpchina.com/bbs/thread-12239-1-1.html
Use $ _ SERVER ["REMOTE_ADDR"] in PHP to obtain the client IP address

However, if the client uses a proxy server to access

The IP address of the proxy server is obtained.

To obtain the real IP address of the client through the proxy server

Use $ _ SERVER ["HTTP_X_FORWARDED_FOR"] to read

However, not every proxy SERVER can use $ _ SERVER ["HTTP_X_FORWARDED_FOR"] to read the real IP address of the client.

Some of the messages read by this method are still the IP address of the proxy server.