brute force attack from local IPv6

I've installed an extra brute force protection with help of this link
http://help.directadmin.com/item.php?id=380
But today I can see the IP of 0:0:0:0:0:0:0:1 which is a local IPv6 is brute forcing my server without being blocked.
"Brute-Force Attack detected in service log from IP(s) 0:0:0:0:0:0:0:1"

How can I block such attacks?

You wouldnt want to block yourself. You are better to find out which account is causing the problem and fix it.