This is what I found (by Jon S. Stevens jon@clearink.com with
Copyright 1998 Jon S. Stevens, Clear Ink)
function validateEmail ($email){
global $SERVER_NAME;
$return = array(false, "" );
list ($user, $domain) = split( "@", $email, 2);
$arr = explode( ".", $domain);
$count = count ($arr);
$tld = $arr[$count - 2] . "." . $arr[$count - 1];
if(checkdnsrr($tld, "MX")) {
if(getmxrr($tld, $mxhosts, $weight)) {
for($i = 0; $i < count($mxhosts); $i++){
$fp = fsockopen($mxhosts[$i], 25);
if ($fp){
$s = 0;
$c = 0;
$out = "";
set_socket_blocking($fp, false);
do {
$out = fgets($fp, 2500);
if(ereg( "^220", $out)){
$s = 0;
$out = "";
$c++;
}
else if(($c > 0) && ($out == "")){
break;
}
else {
$s++;
}
if($s == 9999) {
break;
}
} while($out == "");
set_socket_blocking($fp, true);
fputs($fp, "HELO $SERVER_NAME\n");
$output = fgets ($fp, 2000);
fputs($fp, "MAIL FROM: <info@" . $tld . ">\n" );
$output = fgets($fp, 2000);
fputs($fp, "RCPT TO: <$email>\n");
$output = fgets($fp, 2000);
if(ereg( "^250", $output )) {
$return[0] = true;
}
else {
$return[0] = false;
$return[1] = $output;
}
fputs ($fp, "QUIT\n");
fclose($fp);
if($return[0] == true){
break;
}
}
}
}
}
return $return;
}
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hope it helps you...