Duplicate emails using perl MIME::Lite with smtp

Question

I have an issue sending emails via MIME::Lite module. I have to set some header parameters (return-path and reply-to) therefore I have to use $msg->send('smtp', $SMTP_HOST);

If I understand right in this case the message now sent via Net::SMTP. Unfortunately it results that if an email address is included in both to and cc fields the message is delivered twice. I'm googling for a while now, but I can't figure out what is the reason behind. Can anyone please give me a hint on this?

Thank you in advance!

Answer 1

Mime::Lite just extracts all the recipients from the header, no matter if there are duplicates. They then get used in the dialog to the mail server (e.g. RCTP TO) and if the server sends mails twice if a recipient is given multiple times for the same mail is up to the mail server. Apart from that, why do you include the same recipient as Cc and To anyway?