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From: earle@jplopto.uucp (Greg Earle)
Newsgroups: comp.mail.misc,comp.mail.uucp
Subject: Do `%' and `!' imply (Data link layer) connectivity information?
Message-ID: <5165@elroy.Jpl.Nasa.Gov>
Date: 6 Jan 88 02:45:42 GMT
Sender: news@elroy.Jpl.Nasa.Gov
Reply-To: earle@mahendo.JPL.NASA.GOV (Greg Earle)
Organization: Rockwell International Science Center, Thousand Oaks CA
Lines: 26

(Pardon me if this is explicit in RFC-822, but my copy of that is in a
 storage locker right now awaiting my impending move - sorry)

Does a bang path vs. use of `%' imply any connectivity information?  In
other words, I have more-or-less been assuming that a `%' in a path implied
IP-level connectivity between the primary host and the secondary; e.g.
`foo%bar@blat.Some.DO.MAIN' implied an IP-level link between `blat' and `bar'.
Maybe even implying SMTP service between them.  I also always assumed that
a bang path implied UUCP level connectivity (at least), and possibly IP-level
as well (e.g., those sites running 4.3BSD UUCP over TCP/IP links), but that
part not implied.  But recently I've been seeing things like
	roy%phri@uunet.UU.NET
which threw me for a loop, as I assumed that phri had a UUCP link (perhaps
over Telenet) to uunet, but not an IP-level link.  I assumed that this
setup was definitively described by `phri!roy@uunet.UU.NET' and not with `%'.
Something like `roy%phri.UUCP@uunet.UU.NET' would make more sense, I can
parse this into someone (perhaps on the Internet) wanting to get mail routed
to phri and deciding to let uunet handle the `smart' routing on the UUCP
side, and thus merely specifying the final destination in Internet form.
But `roy%phri' alone is quite a different matter; thus my confusion.

Can someone speak authoritatively to this issue?

	Greg Earle		earle@jplopto.JPL.NASA.GOV
	Indep. Sun consultant	earle%jplopto@jpl-elroy.ARPA	[aka:]
	Rockwell Science Center	earle%jplopto@elroy.JPL.NASA.GOV
	Thousand Oaks, CA	...!cit-vax!elroy!smeagol!jplopto!earle