https://www.cyberciti.biz/faq/how-do-i-block-an-ip-on-my-linux-server/

The Linux firewall can block the ip address using below command:

Block IP address:

# iptables -A INPUT -s 65.55.44.100 -j DROP

Unblock IP address:

# iptables -D INPUT -s 65.55.44.100 -j DROP

Note:

• The Server Agent need Java code to get List of IP address with 404 status and process Linux command to block IP address
• The block and unblock active immediately and no need to restart firewall