Rust

SMTP Inspection

See more SMTP Examples

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

let mailman = chilkat::MailMan::new();

mailman.set_smtp_host("smtp.example.com");
mailman.set_smtp_username("myUsername");
mailman.set_smtp_password("myPassword");

mailman.set_smtp_port(465);
mailman.set_start_tls(true);

let email = chilkat::Email::new();

email.set_subject("This is a test");
email.set_body("This is a test");
email.set_from("Alex <alex@example.com>");
let _ = email.add_to("Christoph", "christoph@example2.com");
let _ = email.add_bcc("Victor", "victor@example3.com");

// Generate the MIME that is sent when SendEmail is called
let mime_str = mailman.render_to_mime(&email).unwrap_or_default();
println!("{}", mime_str);

if mailman.send_email(&email).is_err() {
    println!("{}", mailman.last_error_text());
    return;
}

if mailman.close_smtp_connection().is_err() {
    println!("Connection to SMTP server not closed cleanly.");
}

// Examine the SMTP session log.
println!("----");
println!("Smtp Session Log:");
println!("{}", mailman.smtp_session_log());

// ---------------------------------------------------
// 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