Re: [ietf-smtp] DSNs

Sam Varshavchik <mrsam@courier-mta.com> Wed, 06 May 2020 00:09 UTC

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From: Sam Varshavchik <mrsam@courier-mta.com>
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Date: Tue, 05 May 2020 20:04:48 -0400
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Subject: Re: [ietf-smtp] DSNs
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Viktor Dukhovni writes:

> The internal mailstore topology is none of the sender's concern, but
> also I do not wish to be a source of backscatter if the envelope sender
> address is fake.

Suppressing DSNs won't entirely prevent that. For whatever reason the  
internal mail server may end up bouncing it. The edge server, having  
accepted it and rewritten the recipient address has no guarantees that the  
rewritten recipient's address is deliverable. So it can still bounce and can  
generate backscatter.