Storing sent mails is really one of the oldest problems of the SMTP/IMAP combination.
BURL [1] is an SMTP extension that allows to submit a mail that is already stored on an IMAP server. This still requires to make a separate connection to send the mail, but at least it does not require uploading it to both SMTP and IMAP only to store it in the Sent folder.
However, this extension is rarely implemented or deployed, although the RFC itself is already twelve years old. As an example, Dovecot started to support it by acting as a SMTP proxy [2] as of version 2.3 in 2017. I am not aware of any mail clients that support BURL.
Re:JMAP: Like IMAP but Not Really
by jasonmunro on Friday January 25, 2019 @04:30AM
(#18996700)
JMAP actually does support replacing both. My next TODO item for Cypht is integrating SMTP support with JMAP.
Just curious, did you build Cyrus yourself or there is beta server already?
Re:JMAP: Like IMAP but Not Really
by jasonmunro on Friday January 25, 2019 @11:54PM
(#19004836)
I checked out the git source and built it from there. It was non-trivial to get it built and configured properly for JMAP, but I wanted the latest as the spec is still in flux.
Why do you think you need a new protocol for this? Instead what you want is a different IMAP server.
It has been a long time since I looked at IMAP. Are servers that do this now commonplace? (None I could find used to.)
Can I know from a capability exchange if the remote server will send emails after adding to the "Outbox" folder?
No, not as far as I'm aware. But it's an idea I've also had. Upload the message to drafts, and then when you're ready to send, just move it to Outbox right?
That would be ideal. Keep SMTP as a server-to-server protocol only and IMAP as server-to-client.
Could JMAP replace SMTP as well as IMAP?