Xref: utzoo comp.mail.misc:777 comp.mail.uucp:923
Path: utzoo!utgpu!water!watmath!clyde!rutgers!cmcl2!brl-adm!umd5!uvaarpa!virginia!uvacs!edison!John
From: owens@vtopus.CS.VT.EDU (John Owens)
Newsgroups: comp.mail.misc,comp.mail.uucp
Subject: Re: Do `%' and `!' imply (Data link layer) connectivity information?
Summary: % is a local convention and can mean anything
Message-ID: <1273@edison.GE.COM>
Date: 6 Jan 88 17:43:18 GMT
References: <5165@elroy.Jpl.Nasa.Gov>
Sender: jso@edison.GE.COM
Lines: 19

The % sign in the local-part of an RFC-822 address can mean anything that
the domain wants it to mean.  (It could even be part of a username.)
On most systems, something%somethingelse@this-domain means that the
mailer for this-domain should send the mail to whatever it would take
something@somethingelse to mean.  If uunet wants user@host to imply
user@host.uucp, that's quite reasonable.  On one system I configured,
user@host (or user%host@that-domain) meant that host in the local domain.
In sendmail's delivery ruleset (S0), I would route the hosts via the
appropriate protocol for each.  Some would use UUCP, some SMTP, some
DECNET, etc.

In other words, it's all up to the destination.  (and user%host is much
nicer than host!user because there's no ambiguity of left-vs-right
precedence).

        -John Owens
        Virginia Tech Communications Network Services
        OWENSJ@VTVM1.BITNET    owens@vtopus.cs.vt.edu
        +1 703 961 7827                  vtopus!owens