Various Alternatives to SMTP

I was excited to stumble into this article which showed a brief list of available open source web mail options:
http://www.roseindia.net/opensource/open-source-web-mail.shtml

It can ceate multi-part rich emails which allows you to send encoded images so you don't have to raise security red alerts by referencing images from the web.  The technology it uses to do this is an open-source library named  DotNetOpenMail

SMTP Standards

• WIKIPedia entry for SMTP seems very informative, and guaranteed to be up-to-date.
• 2001 SMTP Standard draft from the The Internet Engineering Task Force (IETF).

Tracking messages using the message-id headeer

I am looking for ways to track email messages using some sort of heading which should be reported in each smtp-log entry. Below is a possible method I plan on experimenting with.

// The Message-ID email header field is treated somewhat specially by the
// Chilkat email component.
// Many SMTP servers will consider emails as duplicates if the Message-ID is identical,
// even if the other parts (subject, body, etc.) are different.  These SMTP servers
// may silently drop duplicates.
// The Chilkat mailman's SendEmail method automatically replaces the Message-ID header
// field in the outgoing email with a unique value.  This behavior can be turned off
// by setting the MailMan.AutoGenMessageId property = false.
// Your program may set a custom Message-ID by calling the Email.AddHeaderField method.

private void custom_message_id()
{
    // Create an instance of the mailman for the purpose of unlocking.
    Chilkat.MailMan mailman = new Chilkat.MailMan();
    mailman.UnlockComponent("Anything for 30-day trial");

    // Turn off the auto-generate message-id feature.
    mailman.AutoGenMessageId = false;

    // Create a new email object...
    Chilkat.Email email = new Chilkat.Email();
    email.Subject = "This is a test";
    email.Body = "This is the mail body";
    email.AddTo("Chilkat Support", "support@chilkatsoft.com");
    email.From = "Chilkat Sales ";

    // Set our own Message-ID
    // The AddHeaderField method will replace a header field if it already exists.
    email.AddHeaderField("Message-ID", "4387ty6wer7g8745e8rtg");

    // Send the email.
    mailman.SmtpHost = "smtp.comcast.net";

    bool success = mailman.SendEmail(email);
    if (!success)
    {
        MessageBox.Show(mailman.LastErrorText);
    }
    else
    {
        MessageBox.Show("Mail Sent!");
    }

}

Kudos to http://www.example-code.com/csharp/message-id-header.asp

How to detect email failures and trying again

See this article for more on the topic