(C++) SMTP under FreeBSD

I need a C++ software that can very fast perform the following action a) getting the mx record for a domain b) connecting to the smtp server (over port 25), sending mail command (the email where we are sending from) and sending a to command (the email where we are sending to) and there it should check for the response on the server. if it says for example mailbox full etc (all this can be handled by status codes that the smtp server sends! Afterall it should verify a big list of opt-in emails we have. Best way would be having it run multi-threading in some kind of way, so it connects to a couple of servers at the same time etc ... Thanks efp ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Complete ownership and distribution copyrights to all work purchased. ## Platform FreeBSD 4.x