====== iptables ======
===== BlockIP =====
  iptables -A INPUT -s IPADDRESS -j DROP
Remove the iptables rule
  iptables -D INPUT -s IPADDRESS -j DROP

===== Log the traffic =====
  iptables -A INPUT -s IPADDRESS -j LOG --log-prefix "Testing "
Then you find the log in /var/log/kern.log