sql-server-2008-r2 .net-3.5 tls1.2 sqlclr

How to enable TLS 1.2 support in SQLCLR 2?

I need to force the usage of TLS 1.2 in SQLCLR assembly which is installed on SQL Server 2008 R2. I have read the answer explaining how to enable TLS 1.2 programatically.

Unfortunately, adding System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolTypeExtensions.Tls12; causes the error The requested security protocol is not supported, even though the Windows Server (2008 R2) is up-to-date (so mentioned Microsoft's hotfix is included).

Does anybody use the same approach in SQLCLR assembly? Is there any other way to support TLS 1.2 in such assembly?

The target framework of the assembly is set to: .NET Framework 3.5

Solution

The answer you linked to actually has the following code, which looks similar to what I have tried myself and gotten to work, and is effectively the same thing as using SecurityProtocolTypeExtensions:

Add this to my code (C#):

public const SslProtocols _Tls12 = (SslProtocols)0x00000C00;
public const SecurityProtocolType Tls12 = (SecurityProtocolType)_Tls12;
ServicePointManager.SecurityProtocol = Tls12

Did you try exactly that? Also, if SQL Server is running on Windows Server 2008 R2, what SP level is the OS at? Reading through the KB article on "Support for TLS System Default Versions included in the .NET Framework 3.5.1 on Windows 7 SP1 and Server 2008 R2 SP1" (linked in the answer you linked to), there are a few possibilities for the "System.NotSupportedException: The requested security protocol is not supported" error:

hotfix is not installed (have you rebooted the OS since updating .NET?)
you SQL Server is running on Windows Server 2008, not 2008 R2

If neither of those are the case, then perhaps explicitly targeting .NET 3.5.1 might work (though I didn't think it was necessary). While you did mention already targeting 3.5.1, I suspect you did this in the app.config file for your project, in which case it will have no effect since SQL Server has no knowledge of that file. SQL Server uses its own app config file located at:

"C:\Program Files\Microsoft SQL Server\MSSQLxx.yyyyy\MSSQL\Binn\sqlservr.exe.config"

where:

"xx" = 2-digit SQL Server version: 2008 / 2008 R2 = 10, 2012 = 11, 2014 = 12, and so on.
"yyyy" = instance name. Default instance name is "MSSQLSERVER".

After making a change to that config file, you at least need to reload user app domains via DBCC FREESYSTEMCACHE(N'ALL');. That should be enough. However, to be 100% certain you can restart the SQL Server instance.