Mailio

For the purpose of message sending, one must connect to an SMTP server, create a message and send it over that connection. The chosen SMTP server further relays the message to the final destination. The well known port 25 is assigned for the unencrypted communication. Sometimes it does not even require authentication, but more often it requires username and password.

So, let's assume that there is an email SMTP server at smtp.server.com and port 25, which has the account mailio@server.com created with the password mailiopass. The non-encrypted connection is created by using the class smtp. Authentication beside the username and password requires also the authentication type as third parameter. The message is created as in the previous chapters. At the end, it is submitted over that connection:

try
{
    smtp conn("smtp.server.com", 25);
    conn.authenticate("mailio@server.com", "mailiopass", smtp::auth_method_t::LOGIN);

    message msg;
    msg.from(mail_address("mailio library", "mailio@server.com"));
    msg.add_recipient(mail_address("mailio library", "mailio@server.com"));
    msg.subject("Salut, tout le monde!");
    msg.content("Hello, World!");

    conn.submit(msg);
}
catch (smtp_error& exc)
{
    cout << exc.what() << endl;
}
catch (dialog_error& exc)
{
    cout << exc.what() << endl;
}

In case one does not need the authentication, the third parameter of smtp::connect() should be smtp::auth_method_t::NONE. Many servers support the plain connection over the port 587, so it can be used too.