On 10/18/2024 7:38 AM, Bill Cole via mailop wrote:
The real original sender is preserved in the Reply-To here (and on
most lists using Mailman today.)
In other words, to get around DMARC fragility and false positive damage,
an intermediary must
1. Break DMARC, by changing the rfc5322.From address to be something
other than the original address
2. Break From semantics, since it no long has the address of the author,
3. Break any existing Reply-to semantics, so it no longer specifies an
address other than the author's, though that's what Reply-to was
define to permit.
Collateral damage abounds.
DMARC has turned the From field into what the Sender field was intended
to provide; it now primarily servies to specify the handling platform.
If the author address survives in the From: field, that is merely a
collateral benefit, but not required.
d/
--
Dave Crocker
Brandenburg InternetWorking
bbiw.net
mast:@dcrocker@mastodon.social
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