On Wed, Nov 12, 2008 at 11:33:46AM -0800, Randy Presuhn wrote: > Huh? Concrete, real example: I send a message to an IETF mailing list. > A list subscriber's ISP rejects the forwarded message. IETF's mailman > drops the subscriber, because this has been happened multiple times. > I can't notify the subscriber, because their ISP also rejects my email. This is not a DNSBL problem. This is a problem with the subscriber's ISP, which is not operating their mail system per de facto best practices -- which include making sure that rejection notices provide an alternate-channel means of contacting them in order to discuss apparently-erroneous blocking. There are a sizable number of techniques for doing this; I happen to think the best ones are quite simple, e.g.: reject=550 5.7.1 <fred@xxxxxxxxxxx>... Mail refused - [201.45.252.2] listed by Spamhaus (http://www.spamhaus.org) - forward this message to nov-13-2008@xxxxxxxxxxx if you believe this is a mistake of course nov-13-2008@xxxxxxxxxxx needs to be exempted from the same blocking and should forward to the postmaster/abuse staff at example.com. There are many other ways to accomplish the same thing at minimal effort and cost; the unifying factor they all share is that recognize that all anti-spam setups have non-zero FP rates, so it's a good idea to be prepared to deal with those situations when they arise. ---Rsk _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf