Date: 4 Aug 1996 21:39:14 -0000
Message-ID: <19960804213914.9783.qmail@koobera.math.uic.edu>
From: djb@koobera.math.uic.edu (D. J. Bernstein)
To: drums@cs.utk.edu
Subject: Re: MX loop example

> Would you relay mail via a site that randomly lost messages?

Would you relay mail via a site that always bounced your messages?

Your claim about costs is unsupportable. Show me a mailer that handles
unauthorized relaying by being irresponsible, and I will show you a
responsible mailer that handles unauthorized relaying LESS EXPENSIVELY.

> You said just a couple of messages ago that no modern mailers
> do that (reject at RCPT).

Please don't take things out of context.

We were talking about slow RCPT responses. A modern mailer will say OK
quickly rather than _taking time_ to verify a RCPT address.

At least two MTAs, qmail and exim, will quickly reject all unauthorized
relaying at the RCPT stage.

> There are lots of reasons why I can't do that in general

Um, how were you planning to decide which messages to throw away?

> The idea is to stop the mail coming anywhere near me.

Don't you think that a bounce will be more effective than silence?

---Dan