I want to write an email transfer service and need a MTU replacement of sendmail/postfix.
I'm not looking how to deliver to a transmitting SMTP server (like a postfix listing on a SMTP port). I also don't need the receiving part of the server, bounces etc. would go to a different existing postfix.
All of it in pure PHP. SMTP is a pretty easy protocol but this would require access to the MX DNS record and other lot of details that need to be taken care of.
Why do i need this? Because most shared internet providers have insane low limits for sending out emails like 500 per day. Thats almost nothing if you want to setup even the lowest traffic email list.
EDIT: Please Note: The code needs to connect to the receivers SMTP server and deliver the message with an adapted header set (removed BCC list, added Path route). If you see a SMTP class less then 5000 lines or requires you to configure a SMTP hostip and port then this is not the stuff i'm looking for.
It needs to do all the stuff sendmail is doing just as a PHP library.