Check if an IP address is private

Question

I like to check if an IP address is in a private network. It doesn't work.

My code:

<?php
$ip = $_SERVER['REMOTE_ADDR'];

function _isPrivate($ip) 
{
    $i = explode('.', $ip);

    if ($i[0] == 10) {
        return true;
    } else if ($i[0] == 172 && $i[1] > 15 && $i[1] < 32) {
        return true;
    } else if ($i[0] == 192 && $i[1] == 168) {
        return true;
    }
    return false;
}
?>

The other one:

<?php
$ip = $_SERVER['REMOTE_ADDR'];

function _isPrivate($ip) 
{
    $ip = ip2long($ip);
    $net_a = ip2long('10.255.255.255') >> 24; 
    $net_b = ip2long('172.31.255.255') >> 20; 
    $net_c = ip2long('192.168.255.255') >> 16; 

    return $ip >> 24 === $net_a || $ip >> 20 === $net_b || $ip >> 16 === $net_c; 
}
?>

Any help would be much appreciated, thanks!

Answer 1

I think this should solve the problem.

filter_var used with the following validation rules will return false if the IP address is a private one.

$user_ip = '127.0.0.1';
filter_var(
    $user_ip, 
    FILTER_VALIDATE_IP, 
    FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE |  FILTER_FLAG_NO_RES_RANGE
)

Check the links above for the php documentation