> -----Original Message-----
> From: exim-users-bounces@??? [mailto:exim-users-bounces@exim.org] On Behalf Of Phil Pennock
> Sent: Friday, April 15, 2011 12:25 PM
> To: exim-users@???
> Subject: Re: [exim] DKIM and mailing lists
>
> Ideally, the mailing-list manager's local MTA will verify DKIM and the
> MLM will strip the inbound DKIM (or rename them to X-Old-*) and then
> sign the messages so that they're verified as coming from the list.
The MLM should definitely re-sign once it has prepared the message for distribution, but the jury's not in on the stripping of old signatures. There are some who believe that they might still contain useful information, assuming they do still verify (there are some MLMs that don't cause such mutations).
The DKIM working group has put forward for publication a document that focuses on DKIM and MLM issues. You might want to take a look if this is an area of interest.
http://datatracker.ietf.org/doc/draft-ietf-dkim-mailinglists/
It's in IETF last call now.
I imagine discussing the content of that is off-topic for this list, however.
-MSK