In internet explorer I open a website. Then click on a button on the web page which makes a secure call to an api located on a 3rd party server.
Is there any way to check what version of ssl/tls is used by internet explorer to make this api call?
I know that I can see IE file-> properties, but this gives me the current connections (web page's) ssl/tls version. Where as I want to see the ssl/tls version used to make the api request (on button click).
The TLS parameters are negotiated during the TLS handshake (when you initially connect to the site) and depend on the browser and server capabilities.
Therefor there is no way to check the capabilities of the browser regarding TLS only from within the browser itself. You need at least to make a https connection to some server which then echos the information from the successful handshake back to you.
For example, in .NET, you can view its version information through ServicePointManager.SecurityProtocol Property. Starting from .NET Framework 4.7, the default value of this property is SecurityProtocolType.SystemDefault. For more information, you can refer to this document.