Swift Mailer can address be banned for mass mailing?

Question

I need to send over 2000 mails and I am using Swift Mailer library for it.

We have own server and it has both SMTP and sendmail transports. I am using SMTP:

$transport = Swift_SmtpTransport::newInstance('localhost', 25);

All mails are send fine to few people, but I'm afraid that we will be banned when we send mass mail. I don't really know what means "banned" and how it looks like, but I'm afraid about the aftermath.

So, is it true, that such "ban" exists and how to implement mass mailing with Swift Mailer in a right way?

P.S.: My code looks like:

    // Create the Transport
    $transport = Swift_SmtpTransport::newInstance('localhost', 25);

    // Create the Mailer using your created Transport
    $mailer = Swift_Mailer::newInstance($transport);

    // Create a message
    $message = Swift_Message::newInstance($message_theme)
      ->setFrom(array($sender => $name))
      ->setTo($emails)
      ->setBody($message_text,"text/html")
      ;
    try {
        // Send the message
        $result = $mailer->send($message);
    }
    catch(Exception $e) {
        echo "Error: ".$e->getMessage();
    }

Answer 1

As I'm hoping you will not use this for spam!!!

Here are some things to do:

• try to same different Emails (change name of the recipient in body)
• send emails once every 3-4 seconds and not 100 emails/second - it should send 2000 emails in about 2-3 hours.