Mail exchange without SMTP server

Is there any way to create a mail server application without using SMTP ser开发者_StackOverflow社区ver in c#?

That depends on what you mean by "mail server". If you mean you want to send and receive mail to other users on different systems, then NO. SMTP is the only protocol in use for this.

If you mean a server that clients connect to, to retrieve the email the server has already received, then there are several protocols, and there is probably room for new ones should they have compelling reasons to use them.

Well, there are other protocols, like IMAP. Here's a couple of IMAP libraries for C#:

http://interimap.codeplex.com/
http://hellowebapps.com/products/imapx/

In fact, from a client's perspective, SMTP typically only works with outgoing messages; you don't receive anything with SMTP (you'd probably end up using POP to receive messages).

Be more specific as to what you are trying to accomplish.

If you are trying to use protocols for what most people refer to as email, then your choices are (AFIAK):

• SMTP for sending mail
• POP/IMAP for receiving mail