Email delivery protocols / methods.

Grant Taylor cctalk at
Mon Jul 8 22:27:07 CDT 2019

I'm combining my replies into one message to avoid spamming the mailing 

Thank you all for intriguing responses.  :-)

On 7/5/19 3:28 PM, Dennis Boone via cctalk wrote:
>>  · FidoNet (FTN)
> As long as we're being silly, this isn't really one protocol. 
> There are a number of different ones, which can probably mostly be 
> characterized as thin wrappers (FTS-0001, Yoohoo(/2u2), etc) around 
> common file transfer protocols (zmodem, xmodem, and others).

Fair enough.

On 7/5/19 3:40 PM, Bill Gunshannon via cctalk wrote:
> Well, if the idea is to get that silly, UUCP isn't one protocol either. 
> And, technically. it isn't for moving email at all.  Like FTP it is 
> for moving files.  It is what happens after the files have been moved 
> that makes email, email.

Also fair enough.

On 7/5/19 4:06 PM, Peter Coghlan via cctalk wrote:
> It's not a holiday in most of the world, including where I am, however...


> BITNET isn't really a protocol.  Perhaps you mean NJE which was the 
> protocol used to implement the BITNET and related networks?

Uh … Ya!  I meant NJE.  ;-)

> Although I think BSMTP (batch SMTP) was usually used to transfer 
> mail over NJE networks.


> (Speaking of which, anyone want to join an NJE network?)

Where can I find out more?

> I have no idea what this one is. "Mail spool" could mean mean all 
> sorts of different things on all sorts of different systems.

I was thinking an MUA accessing files in the mail spool (traditionally 
/var/spool/mail as far as I know) and not using an intermediate protocol 
(POP3 / IMAP / etc.).

> Another one was the coloured book protocol used between academic 
> establishments over X.25 networks in the UK and Ireland and probably 
> elsewhere, Grey maybe, I forget which, probably for the best.


> Then there is DECnet and/or Mail-11…

I don't know how I missed that.

> …depending on what level of protocol you are talking about.

Valid question.  I don't have a distinction at the moment.

> And phonenet which I often heard about but never saw.

I think I have a term collision in my head.  I /think/ I'm thinking of 
Home Phoneline Networking Alliance.

> I worked for an email provider for about 15 years.  We used just 
> about every protocol you can think of to transfer mail to customers, 
> including those already listed plus Kermit / X/Y/Zmodem / Blast (a file 
> transfer package few seem to have heard of) wrapped up in protocols 
> we came up with ourselves which often also used stuff like Zip to 
> compress the data for transmission.  We used them to feed mail into all 
> sorts of email systems long since come and gone, for example CCmail, 
> Microsoft Mail and Pegasus Mail, to name but three from the 1990s.


I think that CCmail / Microsoft Mail / Pegasus Mail were email 
technologies that used shared access to a common "Post Office" 
(directory structure).

On 7/5/19 5:27 PM, Peter Corlett via cctalk wrote:
> I use rsync (over ssh) for transferring between a couple of my mail servers.


I'm curious to know more.  Are  you transferring / synchronizing mail 
boxes?  Or are you using rsync as an intermediate transport between and 
outgoing spool on one system and an incoming spool on another system?

On 7/5/19 5:40 PM, Jason T via cctalk wrote:
> I have vague memories of batch email transfer utilities from the 
> BBS world.  They were readers and/or transfer agents, but I imagine 
> some had their own transfer protocols and file formats. The only two 
> I can recall at the moment were QWK and Blue Wave.  This probably 
> has some tie-in to FIDOnet as well.

I've heard of QWK and "BinkP" is coming to mind for some reason.

On 7/6/19 12:57 PM, Paul Koning via cctalk wrote:
> There's the MAIL-11 protocol (end to end, no MTAs) and the DECmail 
> protocol which may be some OSI-like thing, I'm not sure anymore.

I guess I don't know enough about MAIL-11 to understand why you say 
end-to-end / no MTA.

Was DECmail the OSI X.400 email implementation that DEC produced (I 
think) in the '90s?

> For real strangeness there is the PLATO mail protocol, which involves 
> writing the mail into files, which are then extracted from PLATO into 
> the OS file system by a periodic batch job, then sent to another system 
> via file transfer (FTP or a predecessor), then pushed into the PLATO 
> file system, then picked up by a mail agent at that end.  Ugh.


On 7/6/19 1:33 PM, Chuck Guzis via cctalk wrote:
> Those who quibble about the ftp being a separate entity from mail 
> protocol would do well to look at RFC 524 from 1973.  There, the MAIL 
> command is implemented within the ftp structure (that is, it is an 
> ftp command).


Grant. . . .
unix || die

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