Native OLE DB\SQL Server Native Client 10.0 does not list out the available databases

This held our work for few hours. When we tried to make a connection to SQL Server 2008 server with “Native OLE DB\SQL Server Native Client 10.0” provider from a developer’s machine through SSIS, it did not list out available databases, and did not allow to connect to a database even the name of the database is just typed in the “Select or enter a database name” input box. We doubt that the problem was related to some network problem or to some installed components but, since it allowed to connect with “Native OLE DB\Microsoft OLE DB Provider for SQL Server”, thought that it is related to “SQL Server Native Client 10.0”. We spent hours to find the reason but could not find any issue related to SQL Server components. Though the connection can be established with “Microsoft OLE DB Provider for SQL Server”, since it does not allow to run some of the new TSQLs and specially it does not recognize “Date” data type properly, we had to dig deeper…. Finally, my colleague Buddhika found the issue. Windows Firewall Settings was blocking the Native Client 10.0 requests. Once it is turned off, connection could be established. Again, turning off the settings is not a good practice, we tried to find a way to make a connection while Firewall Settings is on, and we found. Simply, the TCP port 1433 added as an exception for the Firewall Settings. It worked. So, in shorter form, if you cannot make a connection to SQL Server 2008 with Native OLE DB\SQL Server Native Client 10.0” provider, make sure that the SQL Server listening port is added as an exception with Windows Firewall Settings. I am sure that we will be getting the same with Analysis Services too, and adding TCP port 2383 as an exception might solve the issue.