Question

I am using this IP Validation Function that I came across while browsing, it has been working well until today i ran into a problem.

For some reason the function won’t validate this IP as valid: 203.81.192.26

I’m not too great with regular expressions, so would appreciate any help on what could be wrong.

If you have another function, I would appreciate if you could post that for me.

The code for the function is below:

public static function validateIpAddress($ip_addr)
{
    global $errors;

    $preg = '#^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}' .
            '(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$#';

    if(preg_match($preg, $ip_addr))
    {
        //now all the intger values are separated
        $parts = explode(".", $ip_addr);

        //now we need to check each part can range from 0-255
        foreach($parts as $ip_parts)
        {
            if(intval($ip_parts) > 255 || intval($ip_parts) < 0)
            {
                $errors[] = "ip address is not valid.";
                return false;
            }

            return true;
        }

        return true;
    } else {
        $errors[] = "please double check the ip address.";
        return false;
    }
}

Answer 1

Well, why are you doing both regex and int comparisons? You are “double” checking the address. Also, your second check is not valid, as it will always return true if the first octet is valid (you have a return true inside of the foreach loop).

You could do:

$parts = explode('.', $ip_addr);
if (count($parts) == 4) {
    foreach ($parts as $part) { 
        if ($part > 255 || $part < 0) {
            //error
        }
    }
    return true;
} else {
    return false;
}

But as others have suggested, ip2long/long2ip may suit your needs better…