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From: gregc@ucsfcgl.UUCP (Greg Couch%CGL)
Newsgroups: net.mail
Subject: parsing uusite!local@domain-spec - a partial solution
Message-ID: <423@ucsfcgl.UUCP>
Date: Wed, 9-Jan-85 03:59:12 EST
Article-I.D.: ucsfcgl.423
Posted: Wed Jan  9 03:59:12 1985
Date-Received: Fri, 11-Jan-85 23:47:35 EST
Organization: UCSF Computer Graphics Lab
Lines: 83


	How to generate uucp return addresses from the RFC 822 world

The basic problem:

	People want to use the RFC 822 domain addressing standard for all
mail addressing.  Most unix sites support uucp mail and many now support
the RFC scheme as well.  Return addresses given to uucp sites are often
generated assuming that the uucp site doesn't know about RFC 822, which
leads to an ambiguity when the uucp site does try to follow RFC 822.

	The return addresses is often generated as uusite!local@domain-spec.
It is parsed, ()'s for grouping:

	uusite!(local@domain-spec) by uucp-only sites (wanted behavior)
	(uusite!local)@domain-spec by RFC 822 sites - RFC 822 overrides
					(i.e. uusite!local is the local part)

Return addresses need to be generated without assuming that uucp sites
know or don't know about RFC 822.

	The only solution which is compatible with uucp and RFC 822 is not
to give uucp sites addresses with @'s in them.

	I am proposing the following syntax for uucp return addresses
from RFC conforming machines:

		uusite!domain-spec!local

		e.g. ucsfcgl!Berkeley.Arpa!gregc
		or ucsfcgl!ucsfmis.ucsf!gregc		(local top level domain)
		or ucsfcgl!gregc			(no domain-spec)

Why this particular syntax?

	It is a normal uucp address up to the first !.
	It's a RFC 822 conforming address (all local).
	It preserves the locality of the orignal local part.
	! is already special, why use another character?
	It avoids any problems a different special character would create
		since it may mean something special to some other site.
	It's easy to reconstruct the domain address.
	It doesn't break uucp mail.
	It appears to be what usenet uucp-mail project has decided upon
		(we will know soon, I hope).

What this fixes:

	Uucp return addresses are legal for both uucp-only sites and
	RFC conforming sites.

What this breaks:

	It may break sites that try to shorten chains of uucp addresses.
	Sites that use . as a special character with higher precedence
		than !.
	Any other program that parses uucp mail addresses as site!site!....

What this doesn't fix:

	The RFC 822 routing syntax isn't handled correctly, since
		routes can have more than one @.  The hack solution is
		to strip routing information until only one @ is in the
		address and hope that is a good enough (should be, but...).
	Uucp routing isn't solved.
	Mail that goes through sites that don't munge the From: and To:
		fields to RFC conforming site will still cause the mail
		to be unreplyable to.

In short:

	This proposal is only for generating return addresses for consumption
by uucp, it is not a general solution of mail addressing problems.  It is
designed for backward compatibility with uucp-only sites, but at the same
time, for compatibility with sites that are switching to the RFC notation.
I have a generic uucp/ethernet sendmail.cf file with this implemented and
tested, if anyone would like a copy, just send me mail.

Comments to:
			Greg Couch
			ucbvax!ucsfcgl!gregc
			ucsfcgl!gregc@Berkeley.Arpa
			gregc@ucsfcgl.Arpa (as soon as we're published)