Date: 29 Feb 1996 19:54:33 GMT
Message-ID: <19960229195433.20101.qmail@koobera.math.uic.edu>
From: djb@koobera.math.uic.edu (D. J. Bernstein)
To: drums@cs.utk.edu
Subject: Re: comments from a newcomer

> Requiring SMTPs to suddenly become 8-bit was felt to be unacceptably
> harmful to the installed base.

But the current 7-bit requirement is so harmful that thousands, perhaps
millions, of people are forced to _ignore it completely_.

(It wouldn't be so harmful in a completely MIME-ified world---it'd be a
small waste of bandwidth, nothing more---but that's not the real world.)

Why are you deliberately making de jure standards that don't match the
de facto standards?

> Relaying an 8-bit message was known to 
> cause failures or other undesirable behavior in MTAs which were 
> perfectly compliant with the spec in only accepting 7-bit messages.

I've heard this rumor too, but can you find any hosts now that choke
on 8-bit messages?

If I can crash a mailer by sending a few cleverly chosen bytes across a
TCP connection, that mailer is a security disaster. I question the
wisdom of basing standards upon security problems.

> unless you care to argue
> that such conversions should be forbidden outright by the standard, 

The job of an MTA is to communicate. Users understand this, and yell
at people who corrupt messages. Unfortunately, those people use your
7-bit restriction as an excuse for continuing the corruption.

> 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.

Right, but that's no reason for artificial dissonance between SMTP and
the underlying transport protocol.

If you're running SMTP over a 36-bit protocol, for example, you should
be allowed to transmit 36-bit data. Anything else is poor engineering.

A relay shouldn't have to worry about conversions when it has the same
transport protocol on input and output.

---Dan