Message-Id: <199603120518.AAA23239@wilma.cs.utk.edu>
From: Keith Moore <moore@cs.utk.edu>
To: John Gardiner Myers <jgm+@cmu.edu>
cc: drums@cs.utk.edu, moore@cs.utk.edu
Subject: Re: Free insertion of linear-white-space 
In-reply-to: Your message of "Mon, 11 Mar 1996 18:19:04 EST."
             <AlF=HcW00WBwA12HhU@andrew.cmu.edu> 
Date: Tue, 12 Mar 1996 00:18:02 -0500
Sender: moore@cs.utk.edu

> Keith Moore <moore@cs.utk.edu> writes:
> > > > This is an (unmentioned) incompatible change in syntax which would
> > > > outlaw  "this".is."legal".under."RFC822"
> >
> > I've certainly used this syntax before when mapping DECnet mail addresses 
> > to RFC822.  I changed to use the percent-hack when I found that one or two 
> > SMTP  servers wouldn't accept it in a RCPT command.
> 
> Looks like you ran into the exact problem I was trying to fix.  The
> above local-part, while legal in 822, is *not* legal in 821.
 
Yes, this must be resolved.  Should it be made legal in SMTP, or 
made illegal in 822?  The number of SMTP serves that enforce
this restriction has always been small (in my experience), 
those few implementations were significant because they were the
MTAs most often used to gateway between BITNET and Internet.
This isn't as big a problem as it used to be.

> Requiring 822bis parsers to handle that syntax will necessarily
> require a large number of them to *convert* such addresses into legal
> 821 syntax.  This has a relatively high cost.

Maybe not.  If your system generates addresses of the form "foo".bar@domain, 
it's reasonable to expect that your SMTP servers will accept those addresses,
so replies are no problem (modulo routing of outgoing mail through firewalls
or other MTAs not designated by the recipient's domain).  The problem comes
when you want to use such an address as your return address and send mail to
one of the restrictive SMTP servers, which won't accept the MAIL FROM.
But this isn't a burden on UAs that simply want to be able to parse
messages containing such addresses for the sake of backward compatibility.

This is probably one of those issues where the sense of the group (and
its collective experience) is better than that of any one person.  My 
intuitive sense is that we should keep the current local-part syntax, 
(because it is useful), but I won't lose any sleep if the larger part
of the group decides to change it from

word *( "." word )

to

atom *( "." atom )

Keith