.NET Framework 3.5 and TLS 1.2

Question

I currently have a web application using the .NET 3.5 framework, and I am wondering if it is compatible with TLS 1.2. No, where in our code we dictate the TLS version. This is an outdated application, and recompilation is not on the table now. I do not find much information about whether you can or not, but I got the impression that compatibility is more dependent on the OS version. It looks like a minimum of 2008 R2. The goal is to get PayPal to communicate properly from July 1st.

Answer 1

As you can see from the docs , TLS 1.2 is not in the listing for SslProtocols, it was added to the listing in .NET 4.5 (thanks @orhun).

TLS 1.2 .NET 3.5.

, .NET 4.5 , TLS 1.2.

10/11/17

. 2017 Microsoft TLS 1.2 .NET 3.5.1.

Answer 2

.net 3.5.1 TLS 1.2; , @Paulina.

VS 2008 .net 3.5.30729.4926. , :

:

Imports System.Security.Authentication
Imports System.Net

(#):

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

VB.net:

Const _Tls12 As SslProtocols = DirectCast(&HC00, SslProtocols)
Const Tls12 As SecurityProtocolType = DirectCast(_Tls12, SecurityProtocolType)
ServicePointManager.SecurityProtocol = Tls12

: https://support.microsoft.com/en-us/help/3154518/support-for-tls-system-default-versions-included-in-the-.net-framework : , , cs .

Answer 3

TLS 1.2 Framework 3.5.

Microsoft .

.

• TLS Framework 3.5 :

https://support.microsoft.com/en-us/help/3154518/support-for-tls-system-default-versions-included-in-the-.net-framework-3.5.1-on-windows-7-sp1-and-server-2008-r2-sp1

2. • regedit

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\v2.0.50727]

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft.NETFramework\v2.0.50727]

• .reg( , )

( 64- ) ( 32- )

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\v2.0.50727] "SystemDefaultTlsVersions" = DWORD: 00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft.NETFramework\v2.0.50727] "SystemDefaultTlsVersions" = dword: 00000001

• "" ,

  4. , -

, .

Answer 4

I have the same problem as the OP-old.net 3.5 code, which should connect to an external service using tls 1.2.

As mentioned in the accepted answer, there is a patch for tls1.2 released by MS.

After that, they released a patch for Server 2008 (not R2): https://cloudblogs.microsoft.com/microsoftsecure/2017/07/20/tls-1-2-support-added-to-windows-server-2008/

Thus, it should be possible to upgrade to tls 1.2 while server 2008 is still running.