[Mailman-Users] Avoiding DMARC unsubscribes by enabling VERP_PROBES

Mark Sapiro mark at msapiro.net
Sun May 18 03:18:55 CEST 2014

A post in another thread reminded me of something I had overlooked until

If you are a site admin and you are only concerned about users being
unsubscribed because of DMARC policy bounces, and you are not concerned
about the mail delivery issues - i.e., it's OK if they miss the
occasional post from a Yahoo or AOL user; someone else will quote it
anyway ;) - you can set


in mm_cg.py. I added a note about this to the FAQ at

This works because with VERP_PROBES enabled, a user whose bounce score
reaches threshold does not have delivery immediately disabled. Instead,
the user's bounce score is reset and a VERP like probe is sent to the
user. If the probe bounces, the user's delivery is then disabled, but if
the original bounces were for DMARC, the probe won't bounce because it
is From: the list.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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