If the ip is the same, you can use this .htaccess to avoid connections:
<Limit GET HEAD POST>
order deny,allow
deny from 212.227.99.192
deny from 74.54.21.66
deny from 59.106.129.89
deny from 88.241.161.99
deny from 217.26.209.233
deny from 195.225.178.29
</LIMIT>
Did you install mod_security or bad_behaviour?
I have both and both are very useful to block intruders, spammers and hackers