Which of the following code parameters does php obtain the user IP address?

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  Especially in getenv! I have not found the parameters of these constants in the PHP manual !!!! Where is the information about these parameters?

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  Especially in getenv! I have not found the parameters of these constants in the PHP manual !!!! Where is the information about these parameters?

Http://cn2.php.net/manual/zh/reserved.variables.server.php
Are you sure you cannot find it? In addition, you directlyvar_dump($_SERVER)Isn't that clear. Finally this article has an explanation of your code: http://www.cnblogs.com/lmule/archive/2010/10/15/1852020.html

If you test it, you can only obtain'REMOTE_ADDR'.

However, the network environment is complex, browsers are also varied, and the ways to access the Internet are also refreshing.

As for the top'HTTP_X_FORWARDED_FOR'Obviously, this is set by the proxy. If you go through the wall, you should be familiar with it.

In addition, there are a variety of plug-ins, extensions, and so on, also send request headers.

A search engine has a lot of information.
Http://www.w3school.com.cn/php/php_superglobals.asp
Http://blog.csdn.net/shaobingj126/article/details/6794388
Http://baike.baidu.com/view/752598.htm? Fr = aladdin #3