SMTP ERROR: Failed to connect to server: Connection refused (111) – Directadmin Server Fix

By | March 29, 2018
0 Comment

Sometimes users need to send outgoing e-mails with external SMTP servers. Most popular example is PHPMailer with its ability to use free SMTP servers, for example Gmail. Here is the short piece of code, that allows to do this:

<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
 
require './mail/PHPMailer-master/src/Exception.php';
require './PHPMailer-master/src/PHPMailer.php';
require './mail/PHPMailer-master/src/SMTP.php';
 
date_default_timezone_set('Etc/UTC');
 
 
$milo="this is a test";
 
/**
 * This example shows sending a message using PHP's mail() function.
 */
 
//Create a new PHPMailer instance
$mail = new PHPMailer;
 
//Tell PHPMailer to use SMTP
$mail->isSMTP();
 
$mail->SMTPDebug = 0;
 
//Set who the message is to be sent from
$mail->setFrom('example@gmail.com', 'First Last');
//Set who the message is to be sent to
$mail->addAddress('support@example.com', 'John Doe');
//Set the subject line
$mail->Subject = 'PHPMailer test 2 smtp';
 
$mail->CharSet = 'UTF-8';
//Ask for HTML-friendly debug output
$mail->Debugoutput = 'html';
 
$mail->SMTPSecure = 'tls';
$mail->Host = 'smtp.gmail.com';
$mail->Port = 587;
 
//Whether to use SMTP authentication
$mail->SMTPAuth = true;
 
//Username to use for SMTP authentication
$mail->Username = "example@gmail.com";
//Password to use for SMTP authentication
$mail->Password = "yourpassword";
 
$mail->msgHTML($milo);
//Replace the plain text body with one created manually
$mail->AltBody = $milo;
 
//send the message, check for errors
if (!$mail->send()) {
    echo "Mailer Error: " . $mail->ErrorInfo;
} else {
    echo "Message sent!";
}
 
?>

If you have a Directadmin server with csf firewall installed, most probably you will get this message on execution:

SMTP ERROR: Failed to connect to server: Connection refused (111)

Let’s investigate what causes this error. First, we need to change debug level in our script to get all error messages:

$mail->SMTPDebug = 4;

Here is what we are getting:

2018-03-29 13:01:34 Connection: opening to smtp.gmail.com:587, timeout=300, options=array()
2018-03-29 13:01:37 Connection failed. Error #2: stream_socket_client(): unable to connect to smtp.gmail.com:587 (Connection refused) [SMTP.php line 326]
2018-03-29 13:01:37 SMTP ERROR: Failed to connect to server: Connection refused (111)
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

So the problem seems to be with opening port 587 – the script is even unable to connect. Let’s verify if we have this port blocked by firewall:

[root@server ~]# dmesg | grep 587

Most probably our output will look like this:

Firewall: *TCP_OUT Blocked* IN= OUT=eth0 SRC=62.210.90.101 DST=66.102.1.109 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=57285 DF PROTO=TCP SPT=50856 DPT=587 WINDOW=14600 RES=0x00 SYN URGP=0 UID=503 GID=505
Firewall: *TCP6OUT Blocked* IN= OUT=eth0 SRC=fe80:0000:0000:0000:fabc:12ff:fe48:effa DST=2a00:1450:400c:0c06:0000:0000:0000:006d LEN=80 TC=0 HOPLIMIT=64 FLOWLBL=0 PROTO=TCP SPT=45138 DPT=587 WINDOW=14400 RES=0x00 SYN URGP=0 UID=503 GID=505
Firewall: *TCP6OUT Blocked* IN= OUT=eth0 SRC=fe80:0000:0000:0000:fabc:12ff:fe48:effa DST=2a00:1450:400c:0c06:0000:0000:0000:006d LEN=80 TC=0 HOPLIMIT=64 FLOWLBL=0 PROTO=TCP SPT=45138 DPT=587 WINDOW=14400 RES=0x00 SYN URGP=0 UID=503 GID=505

Here’s the catch – our firewall is blocking outgoing connection through this port. We need to unlock it to continue. Here is the solution.

Open /etc/csf/csf.conf in any editor

Scroll to this line:

SMTP_BLOCK = "1"

Change it to

SMTP_BLOCK = "0"

Restart csf:

csf -r

Now you should be able to use your script without any issues.

Related Posts

Leave a Reply