Reverse lookups for IPv6 addresses is a bit of a religious issue. IIRC someone (Johan Ihren?) gave a presentation at a RIPE meeting a few years ago and said it was best not to bother with any PTRs in the reverse zones for IPv6 space. I think his argument was the world was moving away from name-based access controls to things based on crypto tokens, making reverse lookups pointless. That said, my mail server does not accept inbound SMTP if the connecting host fails to have a working reverse DNS entry: this is remarkably good at spam suppression.
We for one welcome our new ID/LOC split overlords :) Still, you will need locator rDNS and the locator space will still be as big... ------------------------------------------------ David Freedman Group Network Engineering Claranet Limited http://www.clara.net