A good way to get the user's IP address in PHP_PHP Tutorial

REMOTE_ADDR can only obtain the IP set in the visitor's local connection, such as the 10. If you use a proxy server, you will not get the IP of the proxy server, but the real IP of the visitor's gateway. If this function is applied to a web page with restricted IP access, others will not be able to access the page even through the proxy server in the restricted IP access segment.

A function is provided below:

Copy the code The code is as follows:

// Define a function getIP()
function getIP()
{
global $ip;

if (getenv("HTTP_CLIENT_IP"))
$ip = getenv("HTTP_CLIENT_IP");
else if(getenv("HTTP_X_FORWARDED_FOR"))
$ip = getenv("HTTP_X_FORWARDED_FOR");
else if(getenv("REMOTE_ADDR"))
$ ip = getenv("REMOTE_ADDR");
else
$ip = "Unknow";

return $ip;
}

// Usage:
echo getIP();

?>

getenv("REMOTE_ADDR") is used to obtain the client's IP address, but if the client uses a proxy server to access, then What is obtained is the IP address of the proxy server, not the real client IP address. To obtain the client's real IP address through the proxy server, use getenv("HTTP_X_FORWARDED_FOR") to read it.

But if the client does not access through a proxy server, the value obtained with getenv("HTTP_X_FORWARDED_FOR") will be empty.

Copy code The code is as follows:

else if(getenv("HTTP_X_FORWARDED_FOR"))
$ip = getenv( "HTTP_X_FORWARDED_FOR");

means that if the value obtained by getenv("HTTP_X_FORWARDED_FOR") is not empty (that is, when the client uses a proxy server), the variable $ip is equal to getenv(" HTTP_X_FORWARDED_FOR") The real IP value obtained.

If the value obtained by the above else if(getenv("HTTP_X_FORWARDED_FOR")) is empty (that is, no proxy server is used), the following line $ip = getenv("HTTP_X_FORWARDED_FOR"); will not be executed. statement.

In this case, it has been confirmed that the client does not use a proxy server, so copy the code

through The code is as follows:

else if(getenv("REMOTE_ADDR"))
$ip = getenv("REMOTE_ADDR");

These two lines of statements obtain the client's IP address, which is also the real IP address.

http://www.bkjia.com/PHPjc/730059.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/730059.htmlTechArticleREMOTE_ADDR can only obtain the IP set in the visitor's local connection, such as 10 set by yourself on a university campus network. X.XXX.XXX series IP, and this function obtains the IP address of the LAN gateway export...