On 7/1/24 12:58, Phillip Hallam-Baker wrote:
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.
Well, the existing anti-abuse system is itself effectively a DoS attack on email, so sooner or later people might start realizing that.
And associating reputations with 32-bit IPv4 source addresses, to the extent it works at all, becomes less and less viable every day.
So the reputation system can lose because there are too many different parties using a particular 32-bit source address, or it can lose because there are so many 128-bit source addresses that the bad guys can just keep using new ones. Either way, it loses, and valid mail doesn't get delivered far too often, and more and more people use something besides Internet email. Which, of course, has been happening already for many years now.
Really that's not an IPv4-vs-IPv6 question. Keith
