I added your idea to my list of reasons for SMTP over IMAP.
SMTP over IMAP
One of the purposes of developing XEXEC was to lead to SMTP over IMAP.
The idea is rather than having a separate configuration for outgoing
email that users would use the already authenticated IMAP session to
transport outgoing email to an SMTP server which would accept it for
outgoing delivery. Such a system would have several advantages.
* Simplicity of setup - Outgoing SMTP goes away.
* Port Blocking - no port 25 blocks to worry about
* Single login - same login for incoming and outgoing email
* Authentication - The person sending the email is the person who
can read email sent to that address
* Single Protocol - Why use both SMTP and IMAP when you can use just
one?
* Copy to server side sent folder - no need to upload the message twice
* Virus Isolation - With port 25 blocked viruses wouldn't be able to
send email.
SENDER (IMAP) -> DOVECOT (local) -> SMTP-OUT (SMTP) ---------> SMTP-IN ->
RECIPIENT (IMAP)
IMAP would be a consumer to server protocol. SMTP would be a server to
server protocol.
