How to check if recipient's email address has no typo : <p>I need to send order confirmations to my customers. Sales people asks for customers email address. But if sales person makes a typo writing down email address, how can I check for it ?</p>

<p>I have a piece of code from php.net. It checks recipients domain and email format but not if email exists. </p>

<p>Let's assume customer's email is like this : someone@domain.com</p>

<p>Code outputs like this :</p>

<p>email someone@domain.com, 0= not ok, 1= ok : 1 &lt;-- correct</p>

<p>email someone@domain.co, 0= not ok, 1= ok : 0 &lt;-- domain typo</p>

<p>email somepne@domain.com, 0= not ok, 1= ok : 1 &lt;-- mailbox typo</p>

<p>It outputs 0 if domain has a typo, but 1 if mailbox part has a typo.</p>

<p>How can I add check for mailbox part in it ?</p>

<p>Code :</p>

<pre><code>&lt;?
/*
This script validates an e-mail adress using getmxrr and fsockopen

1. it validates the syntax of the address.
2. get MX records by hostname
3. connect mail server and verify mailbox(using smtp command RCTP TO:&lt;email&gt;)
When the function "validate_email([email])" fails connecting the mail server with the highest priority in the MX record it will continue with the second mail server and so on..
The function "validate_email([email])" returns 0 when it failes one the 3 steps above, it will return 1 otherwise
*/

$email = "someone@domain.com";
echo "email $email, 0= not ok, 1= ok : ".validate_email($email)."&lt;br&gt;";
$email = "someone@domain.co";
echo "email $email, 0= not ok, 1= ok : ".validate_email($email)."&lt;br&gt;";
$email = "somepne@domain.com";
echo "email $email, 0= not ok, 1= ok : ".validate_email($email)."&lt;br&gt;";

function validate_email($email){
   $mailparts=explode("@",$email);
   $hostname = $mailparts[1];

   // validate email address syntax
   $exp = "^[a-z\'0-9]+([._-][a-z\'0-9]+)*@([a-z0-9]+([._-][a-z0-9]+))+$^";
   $b_valid_syntax=preg_match($exp, $email);

   // get mx addresses by getmxrr
   $b_mx_avail=getmxrr( $hostname, $mx_records, $mx_weight );
   $b_server_found=0;

   if($b_valid_syntax &amp;&amp; $b_mx_avail){
     // copy mx records and weight into array $mxs
     $mxs=array();

     for($i=0;$i&lt;count($mx_records);$i++){
       $mxs[$mx_weight[$i]]=$mx_records[$i];
     }

     // sort array mxs to get servers with highest prio
     ksort ($mxs, SORT_NUMERIC );
     reset ($mxs);

     while (list ($mx_weight, $mx_host) = each ($mxs) ) {
       if($b_server_found == 0){

         //try connection on port 25
         $fp = @fsockopen($mx_host,25, $errno, $errstr, 2);
         if($fp){
           $ms_resp="";
           // say HELO to mailserver
           $ms_resp.=send_command($fp, "HELO microsoft.com");

           // initialize sending mail
           $ms_resp.=send_command($fp, "MAIL FROM:&lt;support@microsoft.com&gt;");

           // try receipent address, will return 250 when ok..
           $rcpt_text=send_command($fp, "RCPT TO:&lt;".$email."&gt;");
           $ms_resp.=$rcpt_text;

           if(substr( $rcpt_text, 0, 3) == "250")
             $b_server_found=1;

           // quit mail server connection
           $ms_resp.=send_command($fp, "QUIT");

         fclose($fp);

         }

       }
    }
  }
  return $b_server_found;
}

function send_command($fp, $out){

  fwrite($fp, $out . "\r\n");
  return get_data($fp);
}

function get_data($fp){
  $s="";
  stream_set_timeout($fp, 2);

  for($i=0;$i&lt;2;$i++)
    $s.=fgets($fp, 1024);

  return $s;
}

// support windows platforms
if (!function_exists ('getmxrr') ) {
  function getmxrr($hostname, &amp;$mxhosts, &amp;$mxweight) {
    if (!is_array ($mxhosts) ) {
      $mxhosts = array ();
    }

    if (!empty ($hostname) ) {
      $output = "";
      @exec ("nslookup.exe -type=MX $hostname.", $output);
      $imx=-1;

      foreach ($output as $line) {
        $imx++;
        $parts = "";
        if (preg_match ("/^$hostname\tMX preference = ([0-9]+), mail exchanger = (.*)$/", $line, $parts) ) {
          $mxweight[$imx] = $parts[1];
          $mxhosts[$imx] = $parts[2];
        }
      }
      return ($imx!=-1);
    }
    return false;
  }
}

?&gt;
</code></pre>
