The problem isn&#x27;t unique to Tor. It&#x27;s anything that allows a spammer to use the same IP address as innocent people, including things that aren&#x27;t exactly legal, like compromised PCs and routers. Which means blocking Tor blocks the people who follow the law but not the people who break the law.<p>And the problem is going to get worse as a result of IPv4 address exhaustion because some ISPs are going to have to start using carrier grade NAT (and some already are). The answer to that is IPv6 as ever, but that has the opposite problem. IPv6 addresses are too cheap to meter and using a thing for proof of stake requires the thing to be scarce.<p>So the thing to show for it is that you can field test your solution prior to the day of Spam Armageddon when a spammer realizes they have a botnet with access to a million billion IPv6 addresses.