Banning IP Addresses
If you are having problems with a particular visitor, you can ban their IP address on WordPress so they can’t leave you any comments.
1. Log in to your WordPress dashboard.
2. In the sidebar, go down to Settings and select Discussion.
3. On this page, scroll down to Comments Blacklist.

Here you can type in any IP addresses that you want to ban from leaving comments. Make sure you leave a line between each IP address.
4. Then click save changes and done.
