In article <CAPt1N1k1wg9mbN-guuarFP0NvX7v-suOY-bP=TDEOCVhK-epmg@xxxxxxxxxxxxxx> you write: >And yet it is still happening, despite there being a great deal of >discussion in the archives... :/ Yes, because at this point, all of the solutions are worse than the problem. See this page for a roundup of DMARC mitigations: http://wiki.asrg.sp.am/wiki/Mitigating_DMARC_damage_to_third_party_mail The work on ARC is coming along fairly fast. There was a second compatibility event a couple of weeks ago among various implementations, and people tell me there should be usable libraries around the end of the year. Once there's an ARC addon for Mailman and we use that, the DMARC damage should drop considerably, without us having to change the way we use our lists. R's, John