This solution will allow you to take a large list of access rules and apply them to an IIS website. Additionally this is done in a file so there is no need to manually add records.
Collect your List of Rules
I used the following as a general blacklist of malicious and spammer client's to block. There are other sources or you may have your own list. Compile all the lists into one file and don't worry about duplicates, the script later on will resolve those.
Convert the Rules to Web.config Equivalents
Ensure you have the Features Installed
Next log onto your server and make sure that you have the Web Server > Security > IP and Domain Restrictions role installed. You may need to add it as it's not selected by default.
Apply your new Rules
Finally open up the web.config files for each of your main sites and add the generated text to the system.webServer/security/ipSecurity section. Save and reload the website to ensure it's working.