Send an SMTP NOOP Command

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Demonstrates the Chilkat MailMan.SmtpNoop method, which sends an SMTP NOOP command to the server. NOOP does nothing except elicit a positive response, which is useful for keeping a connection alive or verifying it is still responsive. This example opens an SMTP connection, sends a NOOP, and closes.

Background: When holding an SMTP connection open across many sends (see OpenSmtpConnection), an idle stretch can cause the server to time out and drop the socket. A periodic NOOP keeps the session active and confirms the server is still responding, so the next SendEmail doesn't fail on a silently-closed connection.

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bool success = false;

//  Demonstrates the MailMan.SmtpNoop method, which sends an SMTP NOOP command to the server.
//  NOOP does nothing except elicit a positive response, useful for keeping a connection
//  alive or verifying it is still responsive.

Chilkat.MailMan mailman = new Chilkat.MailMan();

//  Configure the SMTP server connection.
mailman.SmtpHost = "smtp.example.com";
mailman.SmtpPort = 465;
mailman.SmtpSsl = true;
mailman.SmtpUsername = "user@example.com";
mailman.SmtpPassword = "myPassword";

//  Open the SMTP connection.

success = mailman.OpenSmtpConnection();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

//  Send a NOOP to keep the connection alive.
success = mailman.SmtpNoop();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

success = mailman.CloseSmtpConnection();
if (success == false) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

Debug.WriteLine("SMTP NOOP succeeded.");