Re: [Exim] MX Record points to non-existent host

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Author: Greg Louis
Date:  
To: Exim Users Mailing List
Subject: Re: [Exim] MX Record points to non-existent host
On 20030222 (Sat) at 1806:43 -0500, Greg A. Woods wrote:
> [ On Saturday, February 22, 2003 at 15:16:43 (-0500), Greg Louis wrote: ]
> > Subject: Re: [Exim] MX Record points to non-existent host


> Do you expect your customers to be able to send you e-mail over the
> Public Internet even if they spell your domain name wrong?


"Expect?" If I had a way to make sure they could do that, you can bet
I'd want to apply it. One of my biggest pains is that not even our own
employees can spell the damn thing!

> Sure you can
> go out an register all the obvious mis-spellings, but that just makes
> the problem worse because by doing so you set expectations that you can
> _never_ meet.


Agreed.

> Do you expect your customers to be able to send you e-mail even if they
> operate a broken, or worse, proprietary, TCP stack?


That would be nice :) Look, the point you're making here is valid, I
understand it, I agree with it, but I decline to be the only one in the
whole damn 'net (except for people who can afford to throw away email
from important correspondents) to stand up and try to enforce it!

> Where do you draw the line? I'll tell you where you must (from the
> point of view of all the rest of the members of this community) draw the
> line: right where the RFCs tell you to draw the line.


Gladly -- as long as everyone else in our situation does likewise more
or less simultaneously.

> If you do not do that then you create a huge amount of animosity amongst
> the rest of the Internet community -- among those of us who are not
> willing to put up with an infinite number of subtly incompatible systems
> that are clearly violating all the standards we have agreed upon.


I have found that most members of the Internet community with whom I have
come in contact are reasonable people who recognize the necessity of
living in the world as it is, and not in some imaginary Utopia. They
may deplore, as I do, the need to accomodate the errors of Some Big
Firm and its customers, but they do not (in general) airily demand that
I antagonize our customers, our agents, our suppliers, our employees
and my boss in a Quixotic attempt to achieve the Utopia single-handedly.

> Sure, but here the real problem is exactly the other way around. Only a
> few of the customer you're trying to attract are likely to be running
> with a broken setups.


I wish. I've not sat down and done the arithmetic, but I'd guess we're
looking at around five percent. In the first six days of operating
exim with reasonably tight constraints, I accumulated several _dozen_
user complaints of emails gone astray.

> You are effectively proposing that all the rest of the world should
> break their software too just so that you don't hurt their poor
> ignorant IT guy's feelings.


Not really. I'm saying _I_ want software that is as tolerant of other
peoples mistakes as I can get. What anybody else does is their
business.

> Sure, you can do whatever the heck you want with your systems. However
> if you even suggest to someone that because their broken systems can
> send e-mail to your broken systems then they should be able to send
> e-mail anywhere, and if someone like myself finds out about this, you're
> the one who's really going to get "corrected".


And when did _you_ stop beating your wife?

I will reiterate that all I want is for emails to us to arrive and
emails from us to arrive in the greatest possible number of cases. The
point has been made in this thread that, in the long term, the way to
achieve that is to enforce the standards. I do not disagree, but I
will not assume the role of cannon fodder. (BTW, you may have missed
it: I do _not_ work for an ISP. My employer manufactures and sells
stuff. My users are my fellow employees. Our customers are, for the
most part, not computer people.)

As a matter of fact, I have been preaching RFC conformance to anyone
who will listen for as long as I've been on the 'net (only 8 years or
so, but still...) and I'm not going to stop doing so. But only to
those who evince a willingness to listen. Cold-calling our customers
is not an option.

> The global public Internet really is a community effort. If you want to
> be a member of this community in good standing then you'll seek out and
> help those of your customers who are stumbling along with broken setups.


If someone needs help and knows it, sure, I'll do what I can. I don't
offer driving lessons to the idiots on the road, and I don't offer
networking lessons either. (Even if I knew as much about it as you do,
I would still believe in minding my own business except when explicitly
asked for help.)

> > They just say "everyone else gets our mail." Worse, my users
> > say, "everyone else gets their mail."
>
> Then they are all wrong, perhaps by omission, even if they don't know
> it. You need to correct them and educate them and help them.


Cheap and easy words. The "everyone" is wrong, of course, but the
spirit of the comment is valid. Restricting one's traffic in the way
you would wish results in loss of important communications. That is
the consequence, and the only consequence, unless it were part of an
Internet-wide revolt. It may be somebody else's fault, but it's we who
suffer.

> As for people who buy and use broken software out of ignorance, well the
> same thing applies: They need to be made aware of their poor choice and
> its consequences; and the software company should be informed of the
> problem too (and if they refuse to fix it then perhaps public pressure
> can be brought to bear upon them).


Worked well so far, hasn't it?

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