get_ip.php

<?php

function get_ip() {

		//Just get the headers if we can or else use the SERVER global
		if ( function_exists( 'apache_request_headers' ) ) {

			$headers = apache_request_headers();

		} else {

			$headers = $_SERVER;

		}

		//Get the forwarded IP if it exists
		if ( array_key_exists( 'X-Forwarded-For', $headers ) && filter_var( $headers['X-Forwarded-For'], FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 ) ) {

			$the_ip = $headers['X-Forwarded-For'];

		} elseif ( array_key_exists( 'HTTP_X_FORWARDED_FOR', $headers ) && filter_var( $headers['HTTP_X_FORWARDED_FOR'], FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 )
		) {

			$the_ip = $headers['HTTP_X_FORWARDED_FOR'];

		} else {
			
			$the_ip = filter_var( $_SERVER['REMOTE_ADDR'], FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 );

		}

		return $the_ip;

	}