User warnings for IP 220.245.178.137 

Just thought I should inform you that this IP address is an ISP proxy server in Australia, there are several ban warnings posted under "User Talk" for it. The ISP does give each user a directly internet addressable IP but they are dynamically allocated (IP is DHCP assigned at login, however the subnet does remain the same for a given user as far as I can tell. If possible you may want to switch to x.x.x.0/24 subnet bans behind the proxy using HTTP_FORWARDED_FOR_X to get the range).