netstat -nt | grep ‘:1521’ | awk ‘{print $5}’ | awk -F: ‘{print $1}’ | sort | uniq -c
iptables -L -n
iptables -A INPUT -s 192.168.0.1 -j DROP
iptables -A INPUT -s 192.168.0.1 -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 80 -j DROP