How to bind a computer to username?

Question

Information Security

Good afternoon, there is exchange 2008, they work via IMAP, how can I bind a mail account to a host? to ensure that the letter is sent only from the identified user, enabling smtp authorization is not an option.

Answer 1

Issue personal certificates to employees and sign letters with them. The server is not involved at all. S/MIME is supported. Is it fancy enough?

Answer 2

Well, try implementing S/MIME encryption. But it will be easier to deal with SMTP authorization :)