Not another infected PC or BotNet sending me spam... Well, maybe if you blocked the RATS at the SMTP level of your server, this would not be a problem. We have several lists of IP Addresses that have all the indicators of being RATS, and you can use them just like any of your favourite RBLs.
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Dynamic Regex - Dynamic Regular Expression Testing is part of our suite of tools, used to identify address spaces that are not meant to be mail servers.
MIPSpace - MIPSpace is a list of IP Addresses associated with known commercial marketing companies.