Am Freitag, 4. Dezember 2020, 14:57:10 CET schrieb Per Jessen:
Hans-Peter Jansen wrote:
Am Freitag, 4. Dezember 2020, 13:36:38 CET schrieb Per Jessen:
Michal Suchánek wrote:
No, not really. If I received opensuse lists on my personal e-mail I would be pissed off right now.
Without this change, postings with your corporate address would be quarantined or rejeted by any server that implements DMARC.
That's the point, that I don't grasp, Per. Do you say, that adding a list tag to the subject my eg. mailman results in DMARC invalidation? I cannot find a reference to this in the DMARC description.
If this is discussed elsewhere, could you point me there?
Hi Pete
I think it has been described and discussed a couple of times, but it doesn't hurt to repeat it :-)
Thanks for your patience. Much appreciated.
when a domain (in this example "suse.com") uses DKIM signatures, a hash of the email contents is added to an email. The hash usually includes a selection of headers and the email body.
If any of those headers or the body is altered, the hash no longer matches (when checked on the receiving end) and we have a DKIM failure. With DMARC, the domain specifies what should happen in that case, quarantine or reject.
As others noted, it's mostly a matter of serializing any modification in a correct order, isn't it? Especially, given, that mailman adds a complete footer to every mail (for good reasons). Why is it okay to alter the body, but not the subject? Any alterations had to be done before calculating the hashes anyway. Cheers, Pete