// Block ip
iptables -I INPUT -s xxx.xxx.xxx.xxx -j DROP
// Blocked list
iptables -L INPUT -x --line-numbers
// Unblock ip
iptables -D INPUT -s xxx.xxx.xxx.xxx -j DROP
// Unblock ip (by rule number)
iptables -D INPUT 33
// Range block
iptables -I INPUT -s xxx.xxx.xxx.xxx/24 -j DROP
