[ih] SMTP History

[Dave Crocker]

On 3/28/2022 9:41 AM, Emiliano Spinella via Internet-history wrote:
> Lately, I have been looking for information regarding the history of SMTP
> but could not find much information.
> 
> Basically, I am interested in the initial Email system protocols and how
> SMTP got its final form. I imagine there must have been multiple protocol
> alternatives for Email but somehow SMTP became a standard.
> 
> Were there some relevant milestones that helped SMTP to become broadly
> adopted? I imagine there must have been some important institution or set
> of institutions that drove the adoption.
> 
> Also, is there any reason why POP3 and later IMAP were not part of SMTP?


Emiliano, hello.


1. A partial timeline of email milestones is at <http://emailhistory.org>

2. A far more complete timeline is under development, by Jake Feinler 
and John Vittal.  I don't know when it will be public.

3. There are a number of Internet mail history summaries available 
through online searches. Most of the ones that do not focus on purported 
invention in the late 1970s are reasonable.

4. In  the very early 1970s, the Arpanet FTP protocol -- which has 
mostly transferred to the Internet environment -- was under development. 
  I only went to its final meeting and don't remember whether email was 
in the version; from the RFC publication history, it appears not. 
However Abhay Bhushan, who was the document editor, some years ago told 
me it was always planned.

5. Ray Tomlinson created the first networked email in late 1971.  It 
used a proprietary arrangement, with sndmsg, readmail and cpynet user 
software and file transfer mechanism, specific to BBN's Tenex system. 
But since Tenex was popular around the Arpanet, this usage spread 
quickly within that community. Some years ago, before his death, Ray 
said that his effort on email was in response to discussions that were 
underway amongst the Arpanet folk, for a more elaborate -- and IMO far 
less useful -- protocol to support remote printing of interoffice memos, 
rather than online, person-to-person message exchange.

6. There is much written about the culture of developing Arpanet (and 
Internet protocols.)  The sequence that produced SMTP was an example of 
that culture.  The FTP-based mechanism was in use for about 10 years, 
before SMTP was specified.  There was an effort in the latter 1970s, to 
do an elaborate, multi-media protocol, but it didn't make much progress. 
  The SMTP effort was more modest -- hence the 'S' -- essentially 
seeking only to carve off the email transfer mechanism from FTP, and 
mostly just add the ability to specify multiple recipients, to save 
extra network transfers; it preserved that syntax and semantics of the 
email object that had been transfered in the 1970s.  Network bandwidth 
was a lot slower and more expensive, in those days.

7. Adoption of new protocols, in those days, wasn't very difficult, as 
long as people saw functional or operational benefit.  Small community, 
and easily shared code, and mostly simple protocols.

d/

-- 
Dave Crocker
Brandenburg InternetWorking
bbiw.net