Getting real client IP address in PHP

Many times we need the visitor’s ipaddress for validation, security, spam prevention, etc. Getting the Visitor’s ipaddress is very easy in PHP.

The simplest way to get the visitor’s/client’s ipaddress is using the $_SERVER['REMOTE_ADDR'] or $_SERVER['REMOTE_HOST'] variables. The variable in the $_SERVER array are created by the web server (like apache) and we can use them in PHP.

1 2	// Get the client ip address $ipaddress = $_SERVER['REMOTE_ADDR']

However, sometimes this does not returns the correct ipaddress of the visitor. This can be occur due to reasons like the user is behind a proxy, your apache server is behind a reverse proxy (e.g. varnish), etc. So we can use some other server variables to get the ipaddress.

You can use any of the following 2 functions. Both the functions are equivalent with the difference only in how and from where the values are retrieved. The first one getenv() is used to get the values from PHP’s environment variables and the second one $_SERVER is used to get the values from the web server (e.g. apache).

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// Function to get the client ip address function get_client_ip_env() {     $ipaddress = '';     if (getenv('HTTP_CLIENT_IP'))         $ipaddress = getenv('HTTP_CLIENT_IP');     else if(getenv('HTTP_X_FORWARDED_FOR'))         $ipaddress = getenv('HTTP_X_FORWARDED_FOR');     else if(getenv('HTTP_X_FORWARDED'))         $ipaddress = getenv('HTTP_X_FORWARDED');     else if(getenv('HTTP_FORWARDED_FOR'))         $ipaddress = getenv('HTTP_FORWARDED_FOR');     else if(getenv('HTTP_FORWARDED'))         $ipaddress = getenv('HTTP_FORWARDED');     else if(getenv('REMOTE_ADDR'))         $ipaddress = getenv('REMOTE_ADDR');     else         $ipaddress = 'UNKNOWN';     return $ipaddress; }

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// Function to get the client ip address function get_client_ip_server() {     $ipaddress = '';     if ($_SERVER['HTTP_CLIENT_IP'])         $ipaddress = $_SERVER['HTTP_CLIENT_IP'];     else if($_SERVER['HTTP_X_FORWARDED_FOR'])         $ipaddress = $_SERVER['HTTP_X_FORWARDED_FOR'];     else if($_SERVER['HTTP_X_FORWARDED'])         $ipaddress = $_SERVER['HTTP_X_FORWARDED'];     else if($_SERVER['HTTP_FORWARDED_FOR'])         $ipaddress = $_SERVER['HTTP_FORWARDED_FOR'];     else if($_SERVER['HTTP_FORWARDED'])         $ipaddress = $_SERVER['HTTP_FORWARDED'];     else if($_SERVER['REMOTE_ADDR'])         $ipaddress = $_SERVER['REMOTE_ADDR'];     else         $ipaddress = 'UNKNOWN';     return $ipaddress; }

getenv() is used to get the value of an environment variable in PHP
$_SERVER is an array contains server variables created by the web server.

Note: HTTP_X_FORWARDED_FOR sometimes returns internal or local IP address, which is not usually useful. Also, it would return a comma separated list if it was forwarded from multiple ipaddresses.

Note: This would work only on live site, because on your local host your ip would be one of the internal ip addresses, like 127.0.0.1

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