[ih] principles of the internet

[Dave Crocker]

On 6/3/2010 12:34 PM, John Day wrote:
> At 11:10 -0700 2010/06/03, Dave Crocker wrote:
>> It's worth noting that check-point restart was a later addition to
>> FTP. My impression is that it's had limited uptake.
>
> Really. Later when? It was in the 1973 version. Also in the UK color
> books which actually had a sliding window.

ahh.  forgot that.

>>
>> Email later added data integrity, through MIME Content-MD5, and as a
>> side-effect of content protection through PEM, PGP or S/MIME and, more
>> recently, DKIM, if one is loose about the function. It also added
>> delivery confirmation and error reporting via DSN and MDN
>> notifications. It had non-standardized non-delivery notices pretty
>> much from the start; these were later standardized. These all provide
>> a pretty good platform for developing a re-transmission mechanism, if
>> the sender wishes to pursue it.
>
> Integrity, yes. But not reliability. There is no MPL for mail.

Please re-read the last sentence of my paragraph.


>> (email relaying was also a later value-added mechanism, first through
>> Parc's internal conventions, UUCP such as at Berkeley and CSNet at
>> Udel; later standardized through DNS MX records, but let's not go down
>> that... path.)
>
> Correct. Mail was originally two commands in FTP, but that must have
> been later.

It was also later than initial SMTP, although domain names were built into the 
email work of 1982.  MX wasn't developed and viable for 3-5 more years.

d/

-- 

   Dave Crocker
   Brandenburg InternetWorking
   bbiw.net