Re: [Exim] callout suggestion

On Mon, 2004-02-23 at 13:50 +0000, Philip Hazel wrote:
> There is nothing in the ChangeLog that suggests this has ever been
> changed since recipient callouts were invented at the start of Exim 4.
> Now that I think about it some more, however, I suspect that "<>" was
> used so as to prevent the next server from doing yet another callout. If
> the current MTA has already called out to verify the sender address, it
> is wasteful - and discourteous - to callout-verify it again.

True. But let's paraphrase what you said earlier:

What Exim is trying to achieve is to get an answer to the question "Is
it likely that an attempt to deliver a message from $sender_address to
to this address will succeed?"

Since Exim sends its forwarded messages with sender "$sender_address",
that is what it should use for recipient verify callouts.

In the situation I've described, it's just _broken_ to use '<>'. I'd
rather be discourteous than broken. There are those who argue that _all_
callouts are discourteous -- I happen to disagree.

We could perhaps fall somewhere in the middle by using the easily
cacheable 'postmaster@$primary_domain'. But if the target address is
configured only to accept mail from _certain_ addresses, not including
our postmaster, then that's still broken. Less common I'll grant you --
but it's not good for us to assume that it's not the case.

--
dwmw2