1. Log into your cPanel account.
2. In the "Security" section, click on "IP Blocker" Icon.
3. Under "Add an IP or Range" you should enter the IP Address you wish to block.
4. Click on the "Add" button.
Here is Example:
Single IP Address: 192.168.0.1
Range: 192.168.0.1-192.168.0.40
Implied Range: 192.168.0.1-40
CIDR Format: 192.168.0.1/32
Implies 10.*.*.* -- 192.