DKIM signature rejected

[Christian Brabandt]

On Thu, 20 Feb 2025, Matthias Apitz wrote:

> I've got a reject of an email to a public PostgreSQL mailing list due to
> an issue with my DKIM signature. Attached below. I've sent a test email
> to my company mailbox to see my resulting DKIM signature. It's:
> 
> DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=unixarea.de
> 	; s=blu3434000; h=Content-Transfer-Encoding:Content-Type:MIME-Version:
> 	Reply-To:Message-ID:Subject:To:From:Date:Sender:Cc:Content-ID:
> 	Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc
> 	:Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:
> 	List-Subscribe:List-Post:List-Owner:List-Archive;
> 
> What could be wrong with this and how do I fix this. mutt is sending the
> mail to the SMTP server of my provider 1blu, i.e.  I have in ~/.muttrc:
> 
> set smtp_url="smtps://XXXXXX-guru@smtp.1blu.de:465"

My guess is, adding those list-headers to your DKIM headers breaks DKIM 
verification, since the list server adds those headers and therefore 
your DKIM signature is no longer valid. You should be able to verify, 
that your message to the mutt list does not validate for this reason.

regards,
Christian
-- 
Sinners can repent, but stupid is forever.