4.9.3. Check outgoing mail via SMTP

To check for a secure connection, replace mail.adm.tools with ssl://mail.adm.tools and 25 with 465 on line 34.

flowchart LR h[Hosting account]-->|Port 25|mail.adm.tools mail.adm.tools-->|Message|Recipient

Using file manager or any FTP client in the site root directory, create a smtp_test.php file with this code:

<?php

$login = 'from@example.com'; // instead of from@example.com specify the address of the mailbox created on hosting
$password = 'password'; // instead of password, specify the password of the mailbox created on hosting
$to = 'to@example.com'; // instead of to@example.com, specify the recipient's address

$text = "Hi, checking the SMTP connection."; // message content

// function for getting the server response code
function get_data($smtp_conn) {
    $data = "";
    while ($str = fgets($smtp_conn, 515)) {
        $data .= $str;
        if (substr($str, 3, 1) == " ") {
            break;
        }
    }
    return $data;
}

// forming the header of the message
$header = "Date: " . date("D, j M Y G:i:s") . " +0300\r\n";
$header .= "From: =?UTF-8?Q?" . str_replace("+", "_", str_replace("%", "=", urlencode('Test script'))) . "?= <$login>\r\n";
$header .= "X-Mailer: Test script hosting Ukraine.com.ua \r\n";
$header .= "Reply-To: =?UTF-8?Q?" . str_replace("+", "_", str_replace("%", "=", urlencode('Test script'))) . "?= <$login>\r\n";
$header .= "X-Priority: 3 (Normal)\r\n";
$header .= "Message-ID: <12345654321." . date("YmjHis") . "@ukraine.com.ua>\r\n";
$header .= "To: =?UTF-8?Q?" . str_replace("+", "_", str_replace("%", "=", urlencode('To the recipient of the test message'))) . "?= <$to>\r\n";
$header .= "Subject: =?UTF-8?Q?" . str_replace("+", "_", str_replace("%", "=", urlencode('check'))) . "?=\r\n";
$header .= "MIME-Version: 1.0\r\n";
$header .= "Content-Type: text/plain; charset=UTF-8\r\n";
$header .= "Content-Transfer-Encoding: 8bit\r\n";

$smtp_conn = fsockopen("mail.adm.tools", 25, $errno, $errstr, 10); // connection to mail.adm.tools mail server via port 25
if (!$smtp_conn) { print "Server connection failed"; fclose($smtp_conn); exit; }
$data = get_data($smtp_conn);

fputs($smtp_conn, "EHLO ukraine.com.ua\r\n"); // starting of greeting
$code = substr(get_data($smtp_conn), 0, 3); // check if the server returned an error
if ($code != 250) { print "EHLO greeting error"; fclose($smtp_conn); exit; }

fputs($smtp_conn, "AUTH LOGIN\r\n"); // start of authorization procedure
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 334) { print "Server did not allow to start authorization"; fclose($smtp_conn); exit; }

fputs($smtp_conn, base64_encode("$login") . "\r\n"); // sending the login of the mailbox (on hosting it coincides with the name of the mailbox)
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 334) { print "Error accessing such user"; fclose($smtp_conn); exit; }

fputs($smtp_conn, base64_encode("$password") . "\r\n"); // sending password
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 235) { print "Incorrect password"; fclose($smtp_conn); exit; }

fputs($smtp_conn, "MAIL FROM:$login\r\n"); // sending a MAIL FROM value
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 250) { print "The server refused the MAIL FROM command"; fclose($smtp_conn); exit; }

fputs($smtp_conn, "RCPT TO:$to\r\n"); // sending the recipient's address
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 250 AND $code != 251) { print "The server did not accept the RCPT TO command"; fclose($smtp_conn); exit; }

fputs($smtp_conn, "DATA\r\n"); // sending the DATA command
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 354) { print "Server did not accept DATA"; fclose($smtp_conn); exit; }

fputs($smtp_conn, $header . "\r\n" . $text . "\r\n.\r\n"); // sending message body
$code = substr(get_data($smtp_conn), 0, 3);
if ($code != 250) { print "Message sending error"; fclose($smtp_conn); exit; }
if ($code == 250) { print "Message sent successfully. Server response $code"; }

fputs($smtp_conn, "QUIT\r\n"); // end the sending with QUIT
fclose($smtp_conn); // connection closing
?>

⚠️ Be sure to substitute in the script:

Instead of from@example.com — name of the mailbox.
Instead of password — password of the mailbox.
Instead of to@example.com — recipient's email.

Run the created script by accessing it via a browser at an address like example.com/smtp_test.php.
Check to see if the test message is in the recipient's mailbox.

Important points:

To connect to your Gmail mailbox, use app password, not your Google account password.
The script and library from the example do not collect access data or Google account information.

flowchart LR h[Hosting account]-->|Port 587|Gmail Gmail-->|Message|Recipient

Connect to the hosting via SSH.
Go to the directory of the site where the test script will be located (instead of example.com/www specify your data):
```
cd ~/example.com/www/
```
Install PHPMailer library:
```
composer require phpmailer/phpmailer
```
Create] app password to access your Gmail mailbox.

Using file manager or any FTP client in the site root directory, create a gmail_test.php file with this code:

<?php

$login    = 'from@gmail.com'; // instead of from@gmail.com, specify your Gmail address.
$password = 'app_password'; // instead of app_password, specify the created app password
$to       = 'to@example.com'; // instead of to@example.com, specify the recipient's address

use PHPMailer\PHPMailer\PHPMailer; 
use PHPMailer\PHPMailer\SMTP; 
use PHPMailer\PHPMailer\Exception;
require_once __DIR__ . '/vendor/phpmailer/phpmailer/src/Exception.php'; 
require_once __DIR__ . '/vendor/phpmailer/phpmailer/src/PHPMailer.php'; 
require_once __DIR__ . '/vendor/phpmailer/phpmailer/src/SMTP.php';

$mail = new PHPMailer(true);
try {
    $mail->SMTPDebug = SMTP::DEBUG_SERVER;
    $mail->isSMTP();
    $mail->Host = 'smtp.gmail.com';
    $mail->SMTPAuth = true;
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port = 587;
    $mail->Username = $login;
    $mail->Password = $password;
    $mail->setFrom($login, 'Hosting Ukraine user');
    $mail->addAddress($to, 'John Doe');
    $mail->addReplyTo($login, 'Hosting Ukraine user');
    $mail->Subject = "Gmail SMTP test";
    $mail->Body = 'Hi, test Gmail SMTP connection';
    $mail->send();
    echo "Email message sent.";
} catch (Exception $e) {
    echo "Error in sending email. Mailer Error: {$mail->ErrorInfo}";
} finally {
    $mail->smtpClose();
}

Run the created script by accessing it via a browser at an address like example.com/gmail_test.php.
Check to see if the test message is in the recipient's mailbox.