In your letter dated 25 Oct 2015 20:24:55 -0000 you wrote: >>No idea how flexible mailman is, but how hard would it be to write some >>code that ... > >Instead of guessing, five seconds of googlage found this informative page: > >http://wiki.list.org/DEV/DMARC I guess this is a complex way of saying, no mailman doesn't do that? >Re your suggestion, how many subscribers to IETF lists currently use >gmail? What would happen if they were all summarily ejected? My proposal was not to eject them but to mark them as second class citizens. People who use unresponsive big e-mail providers off load a lot of problems to the community. Using a constant from should be a good incentive to look for alternatives but does not provent people from contributing.