See what rules are already configured
iptables -L
Edit iptables
/etc/iptables.test.rules
Activate these new rules
iptables-restore < /etc/iptables.test.rules
Check the diffÂ
iptables -L
Save the new rules to the master iptables file
iptables-save > /etc/iptables.up.rules
iptables -A INPUT -s IP-ADDRESS -j DROP