Unable To Access DuckDuckGo with Fiddler Everywhere

[Tom]

Hi,
I'm unable to access DuckDuckGo with Fiddler Everywhere. I can connect to DuckDuckGo without Fiddler. I think it's because DuckDuckGo detects Fiddler. Other possibilities are that the Fiddler certificate also supports unsafe TLS 1.0 and TLS 1.1, and their server ignores the request, but I'm not sure. Can you connect to DuckDuckGo, or is this issue exclusive to me? Thanks

This is what I received in the response. 

[Nick Iliev]

Hello Tom,

 

Fiddler Everywhere will use older TLS versions only when the client or the server does not support the newer versions (specifics here), but that is not the case with the DuckDuckGo server and should also not be the case with the browser that acts as a client.

For example, here is what the output looks like while using the Google Chrome browser (also works with the DuckDuckGo browser) and the said endpoint

That said, we noticed that you are using HTTP 1.1, which also worked for us, but you can still explicitly enable HTTPP/2 support in Fiddler Everywhere through the Settings > Connections > Enable HTTP/2 checkbox.

You can also reinstall your Fiddler CA through the Settings > HTTPS > Reset option.

All of the above consider that the error "An existing connection was forcibly closed by the remote host" could be caused by multiple factors, including server throttling, anti-bot measures based on IP address, or it could be just a temporary issue with the server itself.

 

Regards,
Nick Iliev
Progress Telerik