> On Mar 13, 2017, at 10:41 PM, Phillip Hallam-Baker <phill@xxxxxxxxxxxxxxx> wrote: > > Perhaps we should just recognize the fact that SMTP does not really support mailing > lists, it never has and never will. This is absurd, perhaps we can recognize that Yahoo does not support mailing lists, ... SMTP works with lists just fine. In any case, the issue at hand is not even about lists, Gmail imposes more strict constraints on IPv6 senders than IPv4 senders. For now I prefer to send over IPv4 rather than reduce the deliverability of my mail when some fragile "authentication" mechanism fails. Thus no SPF, or DMARC for my domain at present. This trade-off is subject to periodic reassessment, for now that's what works best for me. Some day I may enable outbound DKIM signing, and perhaps (much) later as a last resort SPF. So far, neither have been needed. -- Viktor.