Block UDP 1434 to the server using a firewall
Using the Server Network Utility, you can open the properties on the TCP/IP net-lib and remove all net-libs. This will essentially block all network connections to the SQL Server but local connections are still possible because of the shared memory netlib which can be used by specifying '(local)' or a period (.) for the server name. For automated configurations you can clear the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\MSSQLServer\SuperSocketNetLib\ProtocolList. (For named instances use HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\(instance name)\MSSQLServer\SuperSocketNetLib\ProtocolList). A restart will be required.