misunderstanding scale

Wed Mar 26 21:48:08 UTC 2014

If you can figure out how to store an address and a mask you can have any size entry you want.  Just like a routing table.  This is not insurmountable.

Steven Naslund
Chicago IL

> OTOH, a spammer with a single /64, pretty much the absolute minimum 
> IPv6 block, has more than 18 quintillion addresses and there's not a 
> computer on the planet with enough memory (or probably not even enough 
> disk space) to store that block list.
>

It only takes a single entry if you do not store /128s but that /64. Yes, RBL lookups do not currently know how to handle this, but there are a couple of good proposals around on how to do it.

This would also reduce the risks from cache depletion attacks via DNSxL lookups to IPv4 levels.

Sometimes scale is everything. host-based reputation lists scale easily to
> 3.2 billion host addresses. IPv6, not so easily.
>

As soon as we get away from host-centric-view to a network-block-view, things get pretty straightforward.

-- Matthias