C#

SMTP Inspection

See more SMTP Examples

Examine an SMTP session to view all communications sent to the SMTP server. C#

bool success = false;

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

mailman.SmtpHost = "smtp.example.com";
mailman.SmtpUsername = "myUsername";
mailman.SmtpPassword = "myPassword";

mailman.SmtpPort = 465;
mailman.StartTLS = true;

Chilkat.Email email = new Chilkat.Email();

email.Subject = "This is a test";
email.Body = "This is a test";
email.From = "Alex <alex@example.com>";
email.AddTo("Christoph","christoph@example2.com");
email.AddBcc("Victor","victor@example3.com");

//  Generate the MIME that is sent when SendEmail is called
string mimeStr = mailman.RenderToMime(email);
Debug.WriteLine(mimeStr);

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

success = mailman.CloseSmtpConnection();
if (success != true) {
    Debug.WriteLine("Connection to SMTP server not closed cleanly.");
}

//  Examine the SMTP session log.
Debug.WriteLine("----");
Debug.WriteLine("Smtp Session Log:");
Debug.WriteLine(mailman.SmtpSessionLog);

//  ---------------------------------------------------
//  Sample output:
//  ---------------------------------------------------

//  MIME-Version: 1.0
//  Date: Fri, 06 Mar 2026 16:21:00 -0600
//  Message-ID: <A5DC25990C93EC2676F4FBB2BB3BFA9EB34FF9D3@CHILKAT25>
//  Content-Type: text/plain; charset=us-ascii; format=flowed
//  Content-Transfer-Encoding: 7bit
//  X-Priority: 3 (Normal)
//  Subject: This is a test
//  From: Alex <alex@example.com>
//  To: Christoph <christoph@example2.com>
//  Bcc: Victor <victor@example3.com>
//  
//  This is a test
//  ----
//  Smtp Session Log:
//  220 smtp.example.com ESMTP Amazon WorkMail SMTP Service
//  EHLO MYCOMPUTER<CRLF>
//  250-smtp.example.com
//  250-8BITMIME
//  250-AUTH PLAIN LOGIN
//  250 Ok
//  AUTH LOGIN<CRLF>
//  334 VXNlcm5hbWU6
//  YWRtaW5AY2hpbGthdHNvZnQuY29t<CRLF>
//  334 UGFzc3dvcmQ6
//  {PasswordOrCredentials}
//  235 Authentication successful.
//  MAIL FROM:<alex@example.com><CRLF>
//  250 Ok
//  RCPT TO:<christoph@example2.com><CRLF>
//  250 Ok
//  RCPT TO:<victor@example3.com><CRLF>
//  250 Ok
//  DATA<CRLF>
//  354 End data with <CR><LF>.<CR><LF>
//  {388 bytes} <--- The MIME source of the email (examined via RenderToMime) was sent here.
//  <CRLF>.<CRLF>
//  250 Ok
//  QUIT<CRLF>
//  221 Bye