Fiddler doesn't show Chrome interaction with proxy

[Andrii]

I am developing a Chrome extension that activates a proxy. When I enable the VPN and reload the page, the following steps should occur:

1. The Chrome browser makes a request to the proxy.
2. The proxy sends a response with a 407 code.
3. Chrome should call chrome.webRequest.onAuthRequired and provide credentials to the proxy.

However, I don't see any browser interactions with the proxy server.

Is it possible to observe the interaction between Chrome and the proxy using Fiddler?

[Nick Iliev]

Hello Andrii,

 

You should be able to chain Fiddler to the upstream proxy and thus it will act as an intermediate. Actually, this is how Fiddler Classic will try to work by design - it will try to chain to any pre-existing system proxy automatically. If we are not talking about system proxy, then you also have the option to set manual proxy configuration in Fiddler's gateway options.

That said, note that some VPN tools are not working well or at all with MITM proxies, which could be why your connection fails when there is an active VPN connection.

 

Regards,
Nick Iliev
Progress Telerik