SMPT protocol check of email address at preferred MX host or host.

This returns nothing if email is valid, or a nice descriptive error message. It will split out the domain, lookup the preferred mailhost, connect to it an try to deliver at the given address. If no MX record is found it will try to deliver directly at the SMTP port. Since most mailservers say that the given address has valid syntax the only more waterproof check would be to send mail and wait for a reply.



This is the fullest implementation

By : datasmid

<?php

function checkemail($email){
list($mailbox,$domain) = split('@',$email,2);
$state = 'domain';

// find preferred mailserver
if(getmxrr($domain,$mailhosts,$pref)){
asort($pref);
foreach($pref as $preferred){
$mailserver = $mailhosts[key($pref)];
break;
}
$state = "trying mailserver $mailserver";
$state = mailconnect($mailserver,$email);
}else{
// no mail exchange found try as host
$state = "No MX, trying $domain";
$state = mailconnect($domain,$email);
}
return $state;
}

function mailconnect($mailserver,$email){
$myhostname = $SERVER_NAME;
$connection = fsockopen($mailserver, 25);
if($connection){
$state = "connected to $mailserver";
// Nothing to do with greeting
//$smtpgreeting = fread($connection, 512);

//if($smtpgreeting){
fputs($connection, "HELO $myhostname\r\n");
$hello = fgets($connection, 512);
if($hello){
$state = "chatting to $mailserver: $hello";
fputs($connection, "MAIL FROM: <webserver@$myhostname>\r\n");
$youok = fgets($connection, 512);
if($youok){
$state = "chatting to $mailserver: $youok";
fputs($connection, "RCPT TO: <$newaddress>\r\n");
$recepient = fgets($connection, 512);
$state = "chatting to $mailserver: $recepient";
if(ereg('250',$recepient)){
fputs($connection, "QUIT\r\n");
$deliverable = true;
$state = false;
}elseif(ereg('220',$recepient)){
fputs($connection, "QUIT\r\n");
$deliverable = true;
$state = false;
}else{
$deliverable = false;
$state = "RCPT? $recepient $newaddress";
}
}
}else{
$state = "$mailserver not accepting mail now, please try again.";
}
//}else{
//$state = 'mailserver not greeting me';
//break;
//}
}else{
$state = "$mailserver not listening";
}
return $state;
}
?>

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