Re: DKIM/DMARC test

[Thomas Huth <th.huth@xxxxxxxxx>]

Am Tue, 24 Jun 2025 10:50:54 +0200
schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:

> Le 24/06/2025 à 10:38, Uwe Seimet a écrit :
> > I have just contacted my ISP and they told me that they enabled DMARC for all
> > of their customers about 3 weeks ago. So now I know there was a recent
> > configuration change, indeed.
> > I mentioned to them that I did not get any information about the fact that an
> > email was rejected due to DMARC. They told me that the sending mail server
> > should handle this when an email was rejected, by sending me a separate email
> > telling me so. I don't know if this is the right solution, but even if it is,
> > I can probably not expect tuxfamily to do so (anymore).
> >   
> 
> Good to know, and maybe Eero has the same problem with his ISP.
> 
> This seems to be a common problem with DKIM and mailing lists and it can 
> be handled using ARC to add a chain of servers that signed the email
> 
> https://www.sympa.community/manual/customize/dkim-arc.html
> 
> maybe a possible workaround to test when you post a new message to the 
> mailing list if you want to enable DMARC again : add [hatari-devel] 
> yourself to the subject of the mail, I think the mailing list will then 
> not add a second [hatari-devel] in the subject and your mail will remain 
> unaltered wrt the DKIM signature :)

The "hatari-devel" string is configurable in the configuration panel of the
mailing list. We could try to see whether it works better if we disable the
prefix (done now) ... but of course that means that you cannot distinguish
mailing list mails from normal mails by looking at the subject anymore.

 Thomas