Phillip Hallam-Baker writes: > I don't see that happening for SMTP because the big cost of managing SMTP > services is the anti-abuse system, in fact that is pretty much the only > cost. And going from 32 bits to 128 bits (or 64 if you want to look at it > that way) is simply too much leverage to hand over to the attackers. I'm not sure that's entirely true. ip6 means a near infinite number of addresses per host, but almost always those come out of a local /64 LAN. So instead of doing reputation on ip4 /32s, you do it on ip6 /64s. The addresses get longer, but the number of entries you track is going to be similar. It would be ineresting to examine the "worst 10%" of a few ESP's ip6 bad reputation lists to see if this sort of clustering happens in reality. --lyndon
