Hi,
Introduction of ARC signing and a DMARC DNS record seem to have satisfied Google's bulk sender requirements again: the domain reputation has gone back to High (from Medium since mid-June). Also, mails to GMail addresses from our mailing lists are not being blocked by GMail anymore.
So far, so good. What's not working yet, is the mail forwarding service where users have an @common-lisp.net address where the forward address is hosted by Google. These mails are not being ARC signed; while Exim has an (experimental) feature to apply ARC signing to mails, the maintainer(s) at Debian will not consider enabling it ( https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1058808). There are mail-filters (milters) in the Debian ecosystem which *will* allow ARC signing for this mail flow, but Exim doesn't support milters under the pretense that it is sufficiently extensible not to need that. Which is probably true since they embed a Perl interpreter (why?!). On the other hand, since milters are a generally accepted extension mechanism for mail servers, the combination of positions taken by the Exim developers and the Debian Exim packagers, is rather unfortunately resulting in the fact that we can't forward mail to Google...
I'm open to ideas or options that I may have missed while doing my research for solutions.
Regards,