Message-Id: <199602291814.NAA18575@jekyll.piermont.com>
To: djb@koobera.math.uic.edu (D. J. Bernstein)
cc: drums@cs.utk.edu
Subject: Re: comments from a newcomer 
In-reply-to: Your message of "29 Feb 1996 06:40:37 GMT."
             <19960229064037.17741.qmail@koobera.math.uic.edu> 
Reply-To: perry@piermont.com
Date: Thu, 29 Feb 1996 13:14:32 -0500
From: "Perry E. Metzger" <perry@piermont.com>


D. J. Bernstein writes:
> > The entire purpose of the 7-bit restriction was to prevent conflicts.
> 
> What is an SMTP relay supposed to do if it receives an 8-bit message?
> Rejecting (or corrupting) the message is a violation of ``be liberal
> with what you accept.'' Forwarding the message is a violation of ``be
> conservative with what you send.''

Dan;

Let us recall that it was not that long ago that many of us used
machines which did not have words that were multiples of 8 bits. On
PDP-10 class machines (including Dec-20s), which I still have a warm
spot in my heart for, ASCII was stored in seven bit bytes, packed up
tight in 36 bit words. Such a machine would have had real trouble with
8 bit data being sent to it, since it had no way to store such stuff.

Things have largely changed, but the historical convention was for
SMTP mailers to not assume that the counterparty had the capacity to
deal with 8 bit bytes. Because of that, lots of assumptions were made
over the years about the design of mailers to avoid screwing over a
counterparty.

We are, in fact, easing things up -- consenting ESMTP mailers can
indeed now send eight bit bytes. But we can't assume off the bat that
everything can. Hell, there are still some '20s and emulated '20s on
the net, you know!

Perry