Re: [ietf-smtp] DSNs

Laura Atkins <> Mon, 27 April 2020 08:23 UTC

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Date: Mon, 27 Apr 2020 09:23:02 +0100
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Subject: Re: [ietf-smtp] DSNs
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> On 27 Apr 2020, at 00:56, Sam Varshavchik <> wrote:
> John Levine writes:
>> Not necessarily.  It might be forwarded, it might bounce later.
> It's already known that if you are going to forward your mailbox, you want to get your bounces go somewhere else. The bouncing on forwarded mail are mostly useless to the original sender. The original sender can't do anything about them.
> In this situation I would considering forwarding to be a secondary act that has no bearing on the original mail. The message was delivered to the recipient. The fact that it was forwarded by the recipient's mailbox is a out of scope for DSNs.

Forwarding can happen before the message hits the recipient’s mailbox (sieve, procmail). Also, recipients may have per-user filters to /dev/null mail, before the MUA gets it or afterwards - most MUAs allow for blocking. Often, these are solutions implemented to avoid harassment or abuse and there is a significant security / escalation risk for the people implementing the blocks if the blocks are discovered. 


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