Quoth Dave Cinege on Mon, Mar 13, 2000:
> Paul Walsh wrote:
> > I've been asked by "upstairs" if it's possible, when rejecting mail
> > on the basis of a failed reverse-DNS lookup, to send a message back
> > to the originator explaining why the mail has been rejected and
>
> It is anal retentive and I believe a violation of RFC to do this.
> Not all of us can afford to buy connections that we can get rev-res control.
The ISP should set the reverse DNS entries for its dialup lines.
If it doesn't, well, the customers have got a problem.
OTOH, the customers should send their mail through the ISP's mail
hubs, which must have reverse DNS entries _and_ permit mail from
dialups be relayed through them (unless the said ISP is _really_
clueless).
As to the original question: you probably shouldn't send mail in
this case. The error message Exim generates is usually (and
_certainly_ _must_ be) included in the error message ("bounce")
that the remote (client) MTA generates. So, if the server MTA
generates error such as:
550 User unknown.
... the client MTA must (and almost always does) include
something like the following in the error message:
Could not deliver message, remote MTA said:
<<< 550 User unknown.
So, the short answer is: don't bother. Just generate custom
error messages on the SMTP level. RTFM for details.
Vadik.
--
A fool's brain digests philosophy into folly, science into
superstition, and art into pedantry. Hence University education.
-- G. B. Shaw
