Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!ames!pasteur!ucbvax!decwrl!decvax!ima!minya!jc
From: jc@minya.UUCP (John Chambers)
Newsgroups: comp.mail.uucp
Subject: Re: why you should say "-d rutgers -d sun" in your pathalias command line
Message-ID: <60@minya.UUCP>
Date: 9 Aug 88 03:07:15 GMT
References: <676@bacchus.DEC.COM> <881@vsi1.UUCP> <10135@e.ms.uky.edu>
Organization: (none)
Lines: 45

> The only excuse I've ever heard for this is that "replies along news paths
> are always sub-optimal", never mind that you're not ever supposed to use
> news paths for replies ...

You're wrong there.  For instance, try responding by email to this article.
You will use a news path.  Why?  Well, this machine has 4 neighbors, and 
the news (e.g., this article) is sent to all of them.  There is therefore
no mail path to this machine that is not a reverse news path, and if you
respond successfully, you will have used a news path.  Q.E.D.

> It seems appropriate to say somewhere in here that the only sites which
> have the right to use user@host.uucp are the ones who appear in the maps.

Huh?  I'll use any mail notation I can get my mailer to accept; it's my
machine (;-).  How are you going to tell what notation I used, anyway?
If my mailer converts the original notation to some canonical form, like
host.uucp!user, there's no way you can reconstruct what I typed, and I'll
have violated your rule with impunity.

> ... many lines deleted...
> [Sun rewrites the header to give a reference relative to some internet
>  host rather than leaving it as a bare thing which might or might not
>  be known at the recipients machine ... namely,
> 
> >	From: vixie!paul@Sun.COM
> 
> >This is EVIL and RUDE.  Sun doesn't talk to vixie.UUCP; replies to the
> >message are broken, Sun.COM bounces things that come to it looking like:

It is something even more sinful in a computing environment:  it is
ambiguous.  One of the truly general rules is that you should never
mix ! notation with @ notation.  Such a mail path inherently has two 
valid meanings, and you are trusting the mailer to pick the right one.  
Anyone who's successfully written even one program knows how likely
it is that the little monster will pick the meaning you intended.
(I've wasted a lot of my time illuminating email users as to the
consequences of such a path.  Most of them understand, and wonder
aloud how the email community allows such silliness to continue.)

Isn't email fun?  It's even more fun that theology!  [Though sometimes
I wonder if they aren't converging. ;-]
-- 
John Chambers <{adelie,ima,maynard,mit-eddie}!minya!{jc,root}> (617/484-6393)

[Any errors in the above are due to failures in the logic of the keyboard,
not in the fingers that did the typing.]