PHP Is Ipv 4 Adress
function isIPv4Address($inputString)
{
    $a = explode('.', $inputString);
    foreach ($a as $k => $v) {
        if ( ! is_numeric($v) || $v > 255 || $v === '' || $v !== (string)(int)$v) {
            return false;
        }
    }

    return count($a) === 4;
}

This splits the string by dots and validates each part as a normal IPv4 octet.