Can it capture https that goes out from ubuntu running on windows wsl ?

[orma]

Hello

Yesterday I installed Fiddler, to test it.

I sniff https request to instagram.
(using the filter  CONTAINS   instagram)

Then I tried to do it for my python code, running in terminal window of Ubuntu, on windows wsl.
Nothing appears in the requests and response.

Today I thought to try again and I open the Fiddler, but it sniff NOTHING.
(Even if I clear the filter)

 

Any hints to those two issues ?

Thanks

[Nick Iliev]

Hello Orma,

 

Most terminals do not automatically respect the OS proxy settings, which means that you need to explicitly configure the terminal to use the Fiddler proxy address and port. With Fiddler Everywhere, you have two options:

- Use the Fiddler's terminal instance with preconfigured proxy settings.

or

- Use your own terminal and explicitly configure its proxy settings to point to the Fiddler Everywhere proxy (this option requires additional configuration).

You can also use the following dedicated article that suggests how to configure Fiddler to capture traffic from Python applications:

https://docs.telerik.com/fiddler-everywhere/knowledge-base/capturing-python-traffic 

As for the second issue (Fiddler is not capturing anything on the second run), it is hard to pinpoint what might be happening, but you could try to explicitly ensure that Fiddler Everywhere is set as a system proxy (when and if system capturing mode is used). Alternatively, you can use other capturing modes, like browser capturing mode or terminal capturing mode.

 

Regards,
Nick Iliev
Progress Telerik

[orma]

Hi Nick

Thanks for the answers.

I am not totally understand.

When I first install it, I went to view->prefferences->HTTPS and pressed the "Trust Fiddler CA"
Then I markd V on the "Capture HTTPS traffic" and things start running in the "live view window"

Now I read your articles and when I open a browser from inside Fiddler, or open Terminal, this thing captures data.
But it doesn't capture data from my regular Chrome window.
What went wrong ?

OK.
I found out that I need to move the "little blue button" near system proxy, to "on" so it will start capturing data.

Now:
I don't want to run python from Fiddler's terminal cause I have Windows WSL with Ubuntu on it, and there I installed Python with lots of libraries and stuff, so I don't want to install all of it from scratch on my windows.

How do I set the Fiddler to capture data from the ubuntu ??
(I guess I need to save the PEM file and use the export commands. Am I right ?)

Thanks a lot

Orma

[orma]

No
I had a mistake.
I still don't see anything running on the live view.
It was a browser that I opened from the Fiddler, that showed data "running".

when I user regular Chrom window, I still can't see a thing.

[Nick Iliev]

To capture system traffic from Google Chrome (or from any other application that respects the system proxy settings), use the system capturing mode ("System Proxy" switch toggled ON and with Fiddler CA exported, installed, and trusted).

To set up the system capturing mode (including installation of the Fiddler certificate authority) follow the instructions from the following articles:

https://docs.telerik.com/fiddler-everywhere/installation-and-setup/trust-fiddler-ca#install-the-fiddlers-certificate-authority-manual-approach 

https://docs.telerik.com/fiddler-everywhere/installation-and-setup/quickstart-linux 

Note that the system capturing will capture traffic from browsers but won't automatically capture traffic from some terminal application. For example, setting up a proxy for WSL and Python requires explicitly setting up the http_proxy and https_proxy environment variables (as shown here).

 

[orma]

Hi Nick

Thanks a lot

Now everything is understood and working.

I wish you a very good day

Orma