Description:
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The checkdnsrr and getmxrr functions don't work with domain's that only have a single zero preference MX record.

Reproduce code:
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    $Domain = "gostoni.net";
    echo $Domain;
    // That MX(mail exchanger) record exists in domain check .
    // checkdnsrr function reference : http://www.php.net/manual/en/function.checkdnsrr.php
    if ( checkdnsrr ( $Domain, "MX" ) )  {
        echo "Confirmation : MX record about {$Domain} exists.<br>";
        // If MX record exists, save MX record address.
        // getmxrr function reference : http://www.php.net/manual/en/function.getmxrr.php
        if ( getmxrr ($Domain, $MXHost))  {
                echo "Confirmation : Is confirming address by MX LOOKUP.<br>";