RE: Distributed spam-based DoS in progress

["Dave Hart" <davehart () davehart com>]

> From: Hugo van der Kooij [mailto:hvdkooij () vanderkooij org] 
> Sent: Tuesday 18 February 2003 06:48
[...]
> If a message is undeliverable it will be bounced BUT if the 
> bounce message 
> can not be delivered it will be discarded immediatly to 
> prevent double 
> bounce loops.
>
> See also RFC 2821 section 4.5.5

Would you care to cite where it's said that NDRs and other MAIL FROM:<>
messages must be discarded immediately if the first delivery attempt
fails?  The various mailers I have used continue to retry transmission
until configured timeouts, as with any other outbound message.  When the
mail is an NDR being sent to a bogus domain (such as in response to spam
with a forged sender email), it does clog up the queue for that timeout
period.

Regards,
Dave Hart

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