Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!novavax!twwells!bill
From: bill@twwells.com (T. William Wells)
Newsgroups: news.newusers.questions
Subject: Re: What the % means (was Re: Converting Inter...)
Message-ID: <1990Jan14.132122.18687@twwells.com>
Date: 14 Jan 90 13:21:22 GMT
References: <325@fltk.UUCP> <2193@stealth.acf.nyu.edu> <1160@scorn.sco.COM> <1644@dsac.dla.mil> <21209@kuhub.cc.ukans.edu>
Distribution: usa
Organization: None, Ft. Lauderdale, FL
Lines: 36

In article <21209@kuhub.cc.ukans.edu> HUFF@kuhub.cc.ukans.edu (Steve Huff, U. of Kansas, Lawrence) writes:
: In article <1644@dsac.dla.mil>, nor1675@dsac.dla.mil (Michael Figg) writes:
: > What does the '%' do in an address like this? Is it saying noriega at
: > jail.usu.gov, which is a system that uunet.uu.net knows about?

Roughly.

The most important thing to realize about the '%' is that it does
not have *any* fixed meaning. There might be an RFC somewhere
that says something about it, but I don't know.

That means that in the address a%b@c, a%b is just a name like any
other name, so far as the machines sending your mail to c are
concerned. But once your mail gets to c, it may see the address
a%b and say `hmmmm, I guess I have to fiddle some more before
delivering this'. Typically, what it does then is to change the %
to an @ and then sends the message to the new address. On the
other hand, it might bounce your message with `I don't have a
local user a%b'. It all depends on the site.

As an example, some Bitnet sites, I'm told, have trouble dealing
with mail addressed to my site. If they try to send to
bill@twwells.com, it doesn't go through (in case anyone cares, it
is supposedly because their gateway doesn't understand MX
records, but that is a topic for another time). So, instead, they
mail to bill%twwells.com@uunet.uu.net. Mail to uunet works fine.
Uunet gets a `local' address bill%twwells.com, notes the %,
changes it to an @, and sends the mail off to bill@twwells.com.

In general, however, it is not a good idea to provide addresses
that contain a %. They should only be provided when the normal
addresses won't work for some reason or another.

---
Bill                    { uunet | novavax | ankh } !twwells!bill
bill@twwells.com