China trying to break in my SQL server

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http://serverfault.com – I maintain a server with Window 2008R2, SQL Server 2008R2, Bitwise SSH server and IIS7. The applications that use the SQL server are either websites located on the same machine or use a SSH tunnel to connect to it. Within the windows firewall I have the remote desktop login bound to a series of IP addresses which are allowed to get in. I have done the same with the same IP addresses for the SQL server firewall rules. Yet, I still see some Chinese IP trying to get in my SQL server. How can I block all access to the SQL server for IP addresses that are not in my list? (HowTos)