Cannot set app to use system default TLS version by adding appcontext settings in web.config

Question

According to .net guidance of TLS protocol programming, it suggests to config security via appcontext switch when your project targets on .net 4.6. This way works when add appcontext in app.config for console application. However, it doesn't work when add appconext switch in web.config for website project.

This is the config I add.

<runtime>
   <AppContextSwitchOverrides value="Switch.System.Net.DontEnableSchUseStrongCrypto=false;Switch.System.Net.DontEnableSystemDefaultTlsVersions=false"/>
</runtime>

Jalousie

Answer 1

AppContext switches usage in web config file:

<appSettings>
    <add key="AppContext.SetSwitch:Switch.System.Net.DontEnableSchUseStrongCrypto" value="false" />
    <add key="AppContext.SetSwitch:Switch.System.Net.DontEnableSystemDefaultTlsVersions" value="false" />
</appSettings>

https://github.com/dotnet/docs/issues/6675

Jalousie

while this works, setting <httpRuntime targetFramework="4.7.2" /> may also work. https://mcmap.net/q/668551/-tls-1-2-not-negotiated-in-net-4-7-without-explicit-servicepointmanager-securityprotocol-call – Submerge