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PHP - Advanced Method to Retrieve Client IP Address
<?php
function get_ip_address() {
$ip_keys = array('HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_X_FORWARDED', 'HTTP_X_CLUSTER_CLIENT_IP', 'HTTP_FORWARDED_FOR', 'HTTP_FORWARDED', 'REMOTE_ADDR');
foreach ($ip_keys as $key) {
if (array_key_exists($key, $_SERVER) === true) {
foreach (explode(',', $_SERVER[$key]) as $ip) {
// trim for safety measures
$ip = trim($ip);
// attempt to validate IP
if (validate_ip($ip)) {
return $ip;
}
}
}
}
return isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : false;
}
/**
* Ensures an ip address is both a valid IP and does not fall within
* a private network range.
*/
function validate_ip($ip)
{
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) === false) {
return false;
}
return true;
}
<?php
/**
* Retrieves the best guess of the client's actual IP address.
* Takes into account numerous HTTP proxy headers due to variations
* in how different ISPs handle IP addresses in headers between hops.
*/
function get_ip_address() {
// check for shared internet/ISP IP
if (!empty($_SERVER['HTTP_CLIENT_IP']) && validate_ip($_SERVER['HTTP_CLIENT_IP'])) {
return $_SERVER['HTTP_CLIENT_IP'];
}
// check for IPs passing through proxies
if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
// check if multiple ips exist in var
if (strpos($_SERVER['HTTP_X_FORWARDED_FOR'], ',') !== false) {
$iplist = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
foreach ($iplist as $ip) {
if (validate_ip($ip))
return $ip;
}
} else {
if (validate_ip($_SERVER['HTTP_X_FORWARDED_FOR']))
return $_SERVER['HTTP_X_FORWARDED_FOR'];
}
}
if (!empty($_SERVER['HTTP_X_FORWARDED']) && validate_ip($_SERVER['HTTP_X_FORWARDED']))
return $_SERVER['HTTP_X_FORWARDED'];
if (!empty($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']) && validate_ip($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']))
return $_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];
if (!empty($_SERVER['HTTP_FORWARDED_FOR']) && validate_ip($_SERVER['HTTP_FORWARDED_FOR']))
return $_SERVER['HTTP_FORWARDED_FOR'];
if (!empty($_SERVER['HTTP_FORWARDED']) && validate_ip($_SERVER['HTTP_FORWARDED']))
return $_SERVER['HTTP_FORWARDED'];
// return unreliable ip since all else failed
return $_SERVER['REMOTE_ADDR'];
}
/**
* Ensures an ip address is both a valid IP and does not fall within
* a private network range.
*/
function validate_ip($ip) {
if (strtolower($ip) === 'unknown')
return false;
// generate ipv4 network address
$ip = ip2long($ip);
// if the ip is set and not equivalent to 255.255.255.255
if ($ip !== false && $ip !== -1) {
// make sure to get unsigned long representation of ip
// due to discrepancies between 32 and 64 bit OSes and
// signed numbers (ints default to signed in PHP)
$ip = sprintf('%u', $ip);
// do private network range checking
if ($ip >= 0 && $ip <= 50331647) return false;
if ($ip >= 167772160 && $ip <= 184549375) return false;
if ($ip >= 2130706432 && $ip <= 2147483647) return false;
if ($ip >= 2851995648 && $ip <= 2852061183) return false;
if ($ip >= 2886729728 && $ip <= 2887778303) return false;
if ($ip >;= 3221225984 && $ip <= 3221226239) return false;
if ($ip >;= 3232235520 && $ip <= 3232301055) return false;
if ($ip >= 4294967040) return false;
}
return true;
}
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