Is it reasonable to expect that a residential ISP, that provides a generated reverse resolution to a home IP address, will also provide a matching forward resolution that goes back to the same IP?
I would say that it's entirely reasonable to expect them to match, otherwise attempts to connect to some services will experience delays or failures. Of course, for cheap cookie-cutter consumers you wouldn't want to provide a management interface to allow them to change it, but (if they want it) I would delegate to the users themselves: $ORIGIN ZZZ.YYY.XXX.in-addr.arpa. $GENERATE 0-255 $ NS $._rdns $GENERATE 0-255 $._rdns A XXX.YYY.ZZZ.$ I arranged this as a trial at Ihug/Vodafone; I wonder if it's still there. We would simply assign the user a static IP (*1) in a particular range if they wanted to manage their own DNS, or from a general pool if they did not. -Martin (*1: Of course, they were paying extra for the static IP.)