Could not connect to SMTP host

Question

SMTP Error: Could not connect to SMTP host. Message could not be sent.

Mailer Error: SMTP Error: Could not connect to SMTP host.

I can't seem to find a way to make PHPMailer work under CentOS. Mail work just fine under Windows with XAMPP but I always get this error under Linux.

The SMTP server is a Lotus Domino listening on port 25, CentOS machine has NO firewall at all and the strange thing is that even mail() does not work. It returns nothing (while on Windows returns 1). If I send an email through telnet via CentOS server it works just fine so I don't think it is a network problem. It must be related to PHP but I don't know how.

<?php
require("class.phpmailer.php");
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->Host = "192.168.x.x";
$mail->SMTPAuth = false;
$mail->From = "[email protected]";
$mail->FromName = "XXX";
$mail->AddAddress("[email protected]");
$mail->IsHTML(true);
$mail->Subject = "Test";
$mail->Body    = "Test";
if(!$mail->Send())
{
   echo "Message could not be sent. <p>";
   echo "Mailer Error: " . $mail->ErrorInfo;
   exit;
}
echo "Message has been sent";
?>

Just to clarify the code above works on XAMPP (Windows).

I debugged the error on PHPMailer and error happens here (class.smtp.php method Connect()):

$this->smtp_conn = @fsockopen($host,    // the host of the server
                             $port,    // the port to use
                             $errno,   // error number if any
                             $errstr,  // error message if any
                             $tval);   // give up after ? secs
// verify we connected properly
if(empty($this->smtp_conn)) {
  $this->error = array("error" => "Failed to connect to server",
                       "errno" => $errno,
                       "errstr" => $errstr);
  if($this->do_debug >= 1) {
    echo "SMTP -> ERROR: " . $this->error["error"] . ": $errstr ($errno)" . $this->CRLF . '<br />';
  }
  return false;
}

It looks like it can't open the Socket...

UPDATE: Using $mail->SMTPDebug = 2; as suggested by Alvaro produced this output:

SMTP -> ERROR: Failed to connect to server: Permission denied (13)

There are none. What do you mean by the way? You mean set them as ""? — raz3r
FYI tryed $mail->SMTPAuth = true; $mail->Username = ""; $mail->Password = ""; just now, no luck. — raz3r
Can you paste SMTP info from your php.ini file or phpinfo() ? — GBD
The only two SMTP related variables that I can see with phpinfo() are SMTP (localhost) and smtp_port (25). They have the exact value on Windows as well. I tryed changing SMTP according to my actual IP but it changed nothing. Do I have to restart Apache when I change these values? — raz3r

Álvaro González Álvaro González · Accepted Answer · 2012-11-21T08:54:38

You can enable debug mode with the SMTPDebug property, e.g.:

$mail = new PHPMailer();
// 1 = errors and messages
// 2 = messages only
$mail->SMTPDebug  = 2;

Error messages will be echoed to screen.

Update:

A permission denied error message using fsockopen() suggests that the user PHP runs as is not allowed to open a socket. If you'd double-checked that there's no firewall, it's possible that's a SELinux problem :-?

Could not connect to SMTP host

2 Answers