I post messages from time to time to Spamassassin mailing list, and
several members have been complaining about my DKIM setup - they say
they can't receive my emails because of it. Specifically, the complaint
is that my Exim signs the List-* headers. Now I can't really figure this
one out. There don't seem to be any fine-grained DKIM signing options in
Exim. My messages to the list arrive looking like this:
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
d=open-t.co.uk; s=20170820; h=Content-Transfer-Encoding:Content-Type:
MIME-Version:Date:Message-ID:Subject:From:To:Sender:Reply-To: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;
bh=d0g337Alhc+FWBBtMm7w/Hn67G4jbr0RsFSBcWDK2fc=;
b=Nhn9sI6K1G8+vOfCsguSXGA8+6
0Aap3I3NcIZ3F21rrGivbp2eS+Gz42GAn/NvYrrz9RkYL5/PIqr5a6v8QhEio6KGSO1d/RIZVQMaf
V7qqFyvU8GB3MAYavZa+MsLAOmVgxSk3rSAbE+Bk2RER08QGjwLKxEOotKSy6vXzF25s=;
(sorry for the odd line breaks - it looks ok in the actual header of the
email)
My question is, the list of headers -
"h=Content-Transfer-Encoding:Content-Type:MIME-Version ...." - where
does that get generated? Is it on my Exim box - or further down the
line? Also, why is that preventing users of the mailing list from
receiving my messages?
My setup is fairly simple - Thunderbird -> Exim -> and then direct
sending to the recipient server.
Any hints or pointers to reading material would be much appreciated
