[mrb]

I will also add the mentality of choosing to allow or deny access to your service for millions of IP addresses at a time based on some ill-defined rule or based on the service operator's whim is EXACTLY the same mentality that lead us to the current difficulty of running self-hosted email/outgoing SMTP servers.

"Oh because your dynamic IP address was assigned to and used by shady guys 2 years ago, now you cannot access my website, or all your emails will be flagged as spam."

Don't do that people.