Determine if an IP address is coming from a local network.

gistfile1.aw

/**
 * Is this a local IP?
 * @param {string} $ip The IP address you wish to checkk.
 * @return {boolean} Whether the IP is visiting from a local network.
 */
function isLocalIp($ip){
    // Some local IP ranges.
    $ranges = Array(
        Array('10.0.0.0','10.255.255.255'),
        Array('172.16.0.0','172.31.255.255'),
        Array('192.168.0.0','192.168.255.255')
    );

    // Convert IP to long.
    $ip = ip2long($ip);
    
    foreach($ranges as $i){
        // Check if IP is between the predefined IP ranges.
        if($ip >= ip2long($i[0]) && $ip <= ip2long($i[1])){
            return true;
        }
    }
    return false;
}