Path: utzoo!utgpu!watserv1!watmath!iuvax!mailrus!cornell!parmelee
From: parmelee@wayback.cs.cornell.edu (Larry Parmelee)
Newsgroups: comp.protocols.tcp-ip
Subject: %-Hack .vs. Route Address
Summary: Define it before you require it.
Message-ID: <35783@cornell.UUCP>
Date: 8 Jan 90 15:32:03 GMT
Sender: nobody@cornell.UUCP
Reply-To: parmelee@cs.cornell.edu (Larry Parmelee)
Organization: Cornell Univ. CS Dept, Ithaca NY
Lines: 32

Excuse me for jumping in in the middle of things...

In article <9001060126.AA11937@ucbvax.Berkeley.EDU>
craig@NNSC.NSF.NET (Craig Partridge) writes:
> 
> [...], I'd argue the gateway should have sent stuff
> out as user%hidden@host, [...] .
> 
> Craig

I still think the writers of the Host Requirements RFC screwed up when
they encouraged the "%-hack" over Route-Addresses.  Has anything been
published yet to officially state what the "%-hack" is?  In particular,
how does it relate to the other mail address operators "@" and "!"?
How do you interpret "foo!bar%baz@blef"?

RFC 976 defines how to translate back and forth between uucpish pure
"!" addresses and internet address form, including route-addresses; and
also defines the interpretation of "hybrid" forms containing both "@"
and "!".  It recommends avoiding "%".  I fully agree:  because the 
"%-hack" is not defined, hosts can handle it however they wish,
and what they do may not be what you intended.

Until something/someone officially defines the "%-hack", I will
strongly resist using it, prefering route-addresses as the only
un-ambiguous alternative.  Unfortunately, the Host Requirements RFC
will undoubtedly eventually cause trouble with this approach.  Hopefully
someone will come up with a unified definition of "%", "!", and "@"
before things get too bad.

-Larry Parmelee
parmelee@cs.cornell.edu