(C#) SMTP Inspection

See more SMTP Examples

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

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Chilkat .NET Framework

Chilkat for .NET Core

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