Update .NET web service to use TLS 1.2

We actually just upgraded a .NET web service to 4.6 to allow TLS 1.2.

What Artem is saying were the first steps we've done. We recompiled the framework of the web service to 4.6 and we tried change the registry key to enable TLS 1.2, although this didn't work: the connection was still in TLS 1.0. Also, we didn't want to disallow SLL 3.0, TLS 1.0 or TLS 1.1 on the machine: other web services could be using this; we rolledback our changes on the registry.

We actually changed the Web.Config files to tell IIS: "hey, run me in 4.6 please".

Here's the changes we added in the web.config + recompilation in .NET 4.6:

<system.web>
    <compilation targetFramework="4.6"/> <!-- Changed framework 4.0 to 4.6 -->

    <!--Added this httpRuntime -->
    <httpRuntime targetFramework="4.6" />

    <authentication mode="Windows"/>
    <pages controlRenderingCompatibilityVersion="4.0"/>
</system.web>

And the connection changed to TLS 1.2, because IIS is now running the web service in 4.6 (told explicitely) and 4.6 is using TLS 1.2 by default.

Add the following code before you instantiate your web service client:

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

Or for backward compatibility with TLS 1.1 and prior:

System.Net.ServicePointManager.SecurityProtocol |= SecurityProtocolType.Tls12; 

if you're using .Net earlier than 4.5 you wont have Tls12 in the enum so state is explicitly mentioned here

ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;

Three steps needed:

1. Explicitly mark SSL2.0, TLS1.0, TLS1.1 as forbidden on your server machine, by adding Enabled=0 and DisabledByDefault=1 to your registry (the full path is HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols). See screen for details

   

2. Explicitly enable TLS1.2 by following the steps from 1. Just use Enabled=1 and DisabledByDefault=0 respectively.

NOTE: verify server version: Windows Server 2003 does not support the TLS 1.2 protocol

3. Enable TLS1.2 only on app level, like @John Wu suggested above.

   System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

Hope this guide helps.

UPDATE As @Subbu mentioned: Official guide

For me below worked:

Step 1: Downloaded and installed the web Installer exe from https://www.microsoft.com/en-us/download/details.aspx?id=48137 on the application server. Rebooted the application server after installation was completed.

Step 2: Added below changes in the web.config

<system.web>
    <compilation targetFramework="4.6"/> <!-- Changed framework 4.0 to 4.6 -->
    <!--Added this httpRuntime -->
    <httpRuntime targetFramework="4.6" />
</system.web>

Step 3: After completing step 1 and 2, it gave an error, "WebForms UnobtrusiveValidationMode requires a ScriptResourceMapping for 'jquery'. Please add a ScriptResourceMapping named jquery(case-sensitive)" and to resolve this error, I added below key in appsettings in my web.config file

<appSettings>
      <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
</appSettings>