Cubed Root has it right on.

Most ISPs use a Dynamic IP system for all the routers on their network. They can change frequently and would leave people SOL once their's changed.


I think the best long term solution would be to have an automatic firewall tool. Some templates I would recommend would be fail2ban or denyhosts. These both use "After X attempts and Y failures" approach and is something that I could see being adapted for the mining server.