How to publish the MDaemon Mail Server and access on client's PC to send mail?
The Mdaemon works as a server when it's installed and needs to be configured properly before you can send emails. Luckily, the developers of the application provide a manual to learn how the server needs to be configured to run properly. I've seen that users reported replacing the Microsoft Exchange server successfully with the MDaemon one.
I recommend getting the manual to see exactly how the configuration needs to be done: http://files.altn.com/mdaemon/release/mdaemon_en.pdf