[ih] Design choices in SMTP

[Ralph Holz]

Hi everyone,

During a lecture today, the following question came up: SMTP requires quite
a few round-trips to deliver an email. Why was this design choice made,
i.e., why does a submitting client not just send everything to the server
in one RTT?

Apart from the client-server philosophy at play, I am wondering if that was
because we wanted a receiver to terminate the delivery process as early as
possible, i.e., before sending the body, if anything was amiss.

Does anyone have insights on that or maybe even know a nice write-up? I
checked a few sites that discuss the history of SMTP, but so far no luck
with this aspect.

Many thanks,
Ralph