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Re: Queued Mail or Unreturnable Mail?

2008-05-04 18:40:36

Hi all,

Before this discussion goes further, I want to just get this bit sorted 
out, just in case people don't see a relationship between the two 
contenders in this dilema (as indicated in the Subject line) ...

On Fri, 02 May 2008 05:11:33 -0400, Hector Santos 
Sabahattin Gucukoglu wrote:
1.  I am naive enough to receive mail from non-verifiable senders. 

Yes. <g>

To be sure, it sounds like the right thing to do.  As yet, though, there's 
no justification in doing it other than that queue clogging will often 
result if you don't.  Is it *semantically* correct to reject mail just 
because bounces for the sender are undeliverable?  If it isn't, fine - 
let's get to work on standardising a way for domains to indicate that they 
don't want mail, and they'll live happily ever afterward not knowing that 
mail they originated (or not, but that's irrelevant) didn't get through.  
We can try and fail to deliver our DSNs straight away, keep backup MXs 
working without fuss, etc, etc, and still have nice, clean queues without 
going to extraordinary, expensive lengths to verify sender addresses.

To relate to the original question, then: if we all agreed to keep from 
generating DSNs for mailboxes or hosts we take care of to the best of our 
abilities, and we can do that already using RCPT verification to whatever 
extent which is easy to set up and inexpensive, we'll have the DSN problem 
sorted.  If I accept mail for invalid senders, we can only hope that the 
senders help us out by telling us they don't want mail; we'll deliver mail 
from invalid senders in the usual way, but if we do have to generate a DSN 
it's for some legitimate reason and, should the sender not want them, we'll 
happily throw them away under direction from the sender's DNS.  That's the 
dilema: is our priority mail queues or is it the deliverability of errors?

We'd want deliverable errors, of course, but given a choice of having the 
mail and failing to return a DSN on those rare occasions when it's 
necessary and just not having the mail at all, I know which I'd go for: the 
first.  And since the DSNs are the problem here, destined for nowhere, we 
should, by cooperative increments of DNS zones by the people, gradually get 
rid of the long delays usually associated with queued DSNs.  The incentive 
for publishing whether or not you want mail can easily be that it could be 
used by those who want to reject senders who also happen not to receive, if 
desired.  Besides, you can't argue lost DSNs when the sender is invalid, 
any more than if it were <>; and that's often what these noreply-style 
sender addresses are for.  But somehow, you can argue that losing mail 
isn't cool.


Sabahattin Gucukoglu <mail<at>sabahattin<dash>gucukoglu<dot>com>
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