FYI, I migrated to Mailman 2.1.18-1 shortly after Yahoo decided to break every mailing list on the Internet for no good reason. (It certainly has done nothing to mitigate the ongoing flow of spam, phishing and other abuse coming from Yahoo, which continues pretty much as it has for many years.) I can't recommend it, and I don't say that to denigrate the work of the Mailman developers, which has been (as usual) outstanding, even under duress. The problems I've encountered are that the changes in headers are confusing to lot of subscribers and I still see [some] rejections based on DMARC failures despite using the appropriate settings (supported by dnspython-1.11.1, which is required for 2.1.18-1 to work). I suppose I'd describe it in operational practice as "rickety" or "unreliable", at best. Yahoo has inflicted this on themselves by making an abrupt, ill-advised, unilateral decision without consulting with their peers and considering the large-scale implications of said decision. I don't see a good reason for NANOG's mailing list admins to go through a *lot* of work (including what will likely be user confusion/questions, if my experience is any guide) in order to accomodate this. I think a better approach would be to recommend that mailing list participants who want to actually participate should utilize a mail service appropriate for the purpose. ---rsk