Path: utzoo!lsuc!ncrcan!ziebmef!cks
From: cks@ziebmef.uucp (Chris Siebenmann)
Newsgroups: comp.mail.uucp
Subject: Re: re/routing (was: why you should say "-d ru)
Message-ID: <1988Aug9.130308.18881@ziebmef.uucp>
Date: 9 Aug 88 17:03:07 GMT
References: <676@bacchus.DEC.COM> <881@vsi1.UUCP> <3674@palo-alto.DEC.COM>
Reply-To: cks@ziebmef.UUCP (Chris Siebenmann)
Organization: Ziebmef Public Access BBS/Unix, Toronto, Canada
Lines: 159
In article brisco@pilot.njin.net (Thomas Paul Brisco) writes:
>
>] = vixie@palo-alto.DEC.COM (Paul Vixie) <3674@palo-alto.DEC.COM>
>> = lmb@vsi1.UUCP (Larry Blair) <886@vsi1.UUCP>
>} = kehres@tis.llnl.gov (Tim Kehres) <22350@tis.llnl.gov>
>
>]This depends on what you mean by "all your routing".
>
> What I mean by "all my routing" is all my routing. I only
>have to say "rutgers!foo!user" and let the rutgers mail look
>up the path to site foo. So, it literally does *all my routing*. (I
>don't know how else to say it).
This is a good thing to do. What large numbers of people dislike is
sites that take site!a!b!c!d!e!user (when they talk to a) and reroute
it to be foo!bar!e!user (rerouting it this way is also evil even if
site doesn't talk to a; it should restrict itself to finding a route to
a and leave the rest alone).
>>I have NEVER heard a single good
>>reason for a site to reroute. Rerouting saves the offending site nothing.
>>In fact, they end up having to process the same mail twice when it bounces!
>>[That is a perverse justice]
>
> This is more than a perverse justice. Isn't it logical to you
>that if site A talks to site B then we can infer that site B talks
>to site A? (I've heard rumors that there is a theory stating that
>they both also talk with the same bandwidth, but I'm not sure that
>it's been proved yet ;-)
[A digression:]
This depends by what one means by 'talking' and where the ! path is
coming from. There used to be a site (I know because I used it) that
generated a Path: line on outgoing articles that could not be used for
replies (the mailer on the next-hop machine didn't know it by the name
it was sticking on the Path: line).
> I'm not sure what site you mean by ``the offending site'', but
>I believe that rerouting is a big win for all sites involved.
>
> Let's assume that there exists the following links:
>
> A -> B (local, 9600 baud, direct)
> A -> C (long distance, 1200 baud, daily)
> B -> C (long distance, 9600 baud, hourly)
>
> The obvious thing for the casual user (on A) to send a letter to a
>user on C to do is to route a letter thus: C!user. The routing
I hope not. The obvious thing to do is to send the letter with an
address of user@C.UUCP (or user@C). The mail transport system will
then helpfully figure out how to route the letter, and send it to
B!C!user.
> [proposes A rewrite this as B!C!user, since B advertises cheap
> connections with C, and suggests that this is a win.]
>
...
>] is never nec'ily the same person as . <<>>
>]can be contextual: and aren't nec'ily the same machine.
>]
> baz!bar!user foo!bar!user
> ^ ^
> | |
> +-------------------------------+
>
> What the maps and registry are for is to ensure that they *ARE*
>the same hosts, and consequently the same user. Looks like you've
>been bit by the people that I was flaming originally. Either baz
>or foo are advertising a black hole and should fix their maps.
This is only true for registered hosts. There is no requirement for
registering all the hosts in a bang path; if there were, we could get
rid of bang paths entirely and just use user@site.UUP syntax (except
when the maps are outdated).
In fact, I can think of a local example. My site, ziebmef, talks to a
machine called seeker. It's a local Amiga, and not registered in the
maps (the map coordinators have said in the past that they do not want
personal computer map entries). Since seeker isn't registered, ziebmef
doesn't mention a connection to it in its map entry (a good thing,
too). There's also a seeker in Florida, which is in the UUCP maps.
Now, you decide you want to send mail to the Toronto seeker, and send
it using a bang path (which you have to, since smail sites like
ziebmef don't understand the % hack) such as
rutgers!uunet!mnetor!lsuc!ncrcan!ziebmef!seeker!wjr
(for the sake of argument, assume rutgers has a direct uunet connection)
rutgers comes along and says 'aha! by my magic powers of deduction, I
know this is going to wjr@seeker.UUCP', looks up seeker, and routes it
to Florida, where the Florida seeker will bounce it (if you're lucky
-- if you're not, the Florida seeker also has a user called 'wjr').
> According to the maps, it is *not* doing a `wrong thing', but
>is only reflecting the bogosity in the maps written by either
>the administrator at site foo or site baz.
What if foo's map entry doesn't show their connections to bar? This
is legal (and might be done, for example, because bar is really
bar.hiho.com, and there's already a different bar machine in the
maps).
>(thanks, Tim). The only thing I've seen so far is that if you don't
>care enough about the net to keep your maps updated, or complain to
>the people who don't keep their maps updated, OR simply prefer
>to do the wrote/repetitive tasks that computers were designed for
>(like figuring out a path between site foo and baz) - then you
>should not use the routing information available to you.
The mail transport agent should use the routing information available
to it -- but only when handed an address, not a route. If I know
enough to specify a route, I probably have a pretty good reason to do
so. Perhaps the message I'm sending to C!user (to use the first
example) is sensitive business correspondence, or a large file that B
won't appreciate spending LD changes on, or B is down for a few days
and the administrator on A hasn't bothered updating the path database
yet.
Once I specify a route as opposed to an address, by gollee, I don't
want it rewritten. Sure, bounce it -- that's fine. But don't reroute
my mail for Ontario to Florida.
> It seems that if we lived in the "best of all possible
>worlds" (i.e. where all admins kept their maps updated) then the
>arguments that I've heard would fall to the ground. If
>you choose to mark rutgers dead (and it sounds like you'll be marking
>mcvax dead soon, too), I'm sure they'll be very happy to not have
>your mail passing through their machines.
It can take up to two months to have a map change propagate out
through the uucp maps in comp.mail.maps. What do you propose we do in
the mean time?
> Yes - it is very frustrating to have a letter disappear
>down a black hole. I do not, however, think that this means that
>I should do my routing by hand - I tend to blame the person advertising
>a bogus route.
This is why people should use addresses, instead of routes. Routes
are a last resort when you can't get a working address; when you're on
your last resort, it's very irritating to have rutgers bounce your
mail because it thought it knew more than you did.
In this day of wide smail and sendmail availability, there is no
reason why any system can't have a system that uses '@' addresses.
There's not even a requirement for uucp-only sites to keep around the
full maps (smail will punt unknown addresses to a defined host for
you). Given this, we should treat bang paths as what they are, namely
routes, instead of a form of addresses.
--
"Oh BLESS you, sir! The ANGEL OF DEATH was after me just as SURE as
you're standing there, yes he WAS!"
Chris Siebenmann uunet!utgpu!{ontmoh!moore,ncrcan}!ziebmef!cks
cks@ziebmef.UUCP or .....!utgpu!{,ontmoh!,ncrcan!brambo!}cks