php - 使用 PHP EHLO 进行 SMTP 验证

Question

我正在尝试进行电子邮件验证，但似乎无法进行。目前它会与域建立连接，但之后似乎超时。有人知道为什么吗？好像卡在这里:

$res=fgets($connection, "EHLO $mydomain\n");

谁能告诉我这是为什么？我的代码如下:

if(isset($_POST['email']) && filter_var($_POST['email'], FILTER_VALIDATE_EMAIL))

{

 // Could get this from the php ini? 
  $from="xxxx@xxxx-int.net";
 $to=$_POST['email'];
 $subject="Test";
 $message="Testing";
 list($me,$mydomain) = split("@",$from); 

 // Now look up the mail exchangers for the recipient 
 list($user,$domain) = split("@",$to,2); 
 if(getmxrr($domain,$mx,$weight) == 0)  return FALSE; 

 // Try them in order of lowest weight first 
 array_multisort($mx,$weight); 
 $success=0; 

 foreach($mx as $host) { 
  // Open an SMTP connection 
  $connection = fsockopen ($host, 25, $errno, $errstr, 1); 
  if (!$connection) 
    continue; 
  $res=fgets($connection); 
echo $res;
  if(substr($res,0,3) != "220") echo $res;

  // Introduce ourselves 
  fputs($connection, "EHLO $mydomain\n"); 
  $res=fgets($connection); 
echo $res;
  if(substr($res,0,3) != "250") echo $res; 

  // Envelope from 
  fputs($connection, "MAIL FROM: $from\n"); 
  $res=fgets($connection); 
echo $res; 
  if(substr($res,0,3) != "250") echo $res; 

  // Envelope to 
  fputs($connection, "RCPT TO: $to\n"); 
  $res=fgets($connection); 
echo $res; 
  if(substr($res,0,3) != "250") echo $res;

  // The message 
  fputs($connection, "DATA\n"); 
  $res=fgets($connection); 
echo $res; 
  if(substr($res,0,3) != "354") echo $res;

  // Send To:, From:, Subject:, other headers, blank line, message, and finish 
  // with a period on its own line. 
  fputs($connection, "To: $to\nFrom: $from\nSubject: $subject\n$message\n.\n"); 
  $res=fgets($connection); 
echo $res; 
  if(substr($res,0,3) != "250") echo $res;

  // Say bye bye 
  fputs($connection,"QUIT\n"); 
  $res=fgets($connection); 
echo $res; 
  if(substr($res,0,3) != "221") echo $res;

  // It worked! So break out of the loop which tries all the mail exchangers. 
  $success=1; 
  break; 
 } 
 // Debug for if we fall over - uncomment as desired 
 // print $success?"Mail sent":"Failure: $res\n"; 
 if($connection) { 
  if($success==0) fputs($connection, "QUIT\n"); 
  fclose ($connection); 
 } 
 return $success?TRUE:FALSE; 
}

Answer 1

  fputs($connection, "EHLO $mydomain\n"); 

你只在最后发送换行，但是smtp rfc需要 CRLF。这会导致您的脚本“挂起”，因为电子邮件服务器不会响应您的无效行结尾。你必须将其更改为

  fputs($connection, "EHLO $mydomain\r\n");

等等

请注意，在许多情况下，电子邮件验证将不起作用，即使您让脚本与 RFC 兼容的 SMTP 对话。许多服务器简单地接受(然后退回)所有发给无效收件人的邮件。其他人在数据阶段进行收件人验证，而不是 rcpt to (exchange 2013..sigh) 等。