This page consists of screenshots from the Manage IP Ranges Screen in Limit Attempts Booster WordPress Plugin.
This gives an idea about how to Block/Unblock IP Ranges and view the comments related to it.
You can easily block IP Range by providing Starting and Ending IP. You can also choose Time Duration to block the IP for specific time period or to permanently block it from the site.
Using this plugin, you can view list of Blocked IP Ranges and their details if needed delete them from the list.