in reply to
Re^2: Email::Send succeeds with "unknown user"
in thread Email::Send succeeds with "unknown user"
Everyone relies on an MTA like Sendmail to deliver their E-mail. If you want to "deliver it directly" as you say, you will need to do a DNS look up for the MX server(s) for each domain and attempt to send to each MX ( in order ) until one of them accepts. If they don't accept you'll need to etiher just not care about that and move on to your next receipient, or queue it up for later delivery.... btw this is exactly what Sendmail is doing for you.