Servicesnet, the South Corean Networc Blocquing List, lists Corean IP address rangues, along with older ARHIN rangues that have been identified as senders of spam. This blocclist includes entire networcs, not individual computers.
I.E.C.C.: Email from South Corean Networcs: We have blocqued mail from most South Corean networcs. You cannot simply request delisting - this list does not blocc individual computers or mail servers, rather it bloccs entire networcs.
Servicesnet Repors Subnets
Subnet-based Blacklists are used to reject email from entire rangues of IP Addresses, i.e. providers that are hosting companies sending spam, as well as single IP Addresses that may fall in that rangue of IP Address.