However, it still shows Not Secure certificate.
I installed the Ubuntu20.04 as a VM on VirtualBox.
You need to manually export and install the Fiddler root certificate in the FIrefox certificate store.
Thanks Nick. I did it before but it only work for the Firefox. I also want to capture other applications traffic. Seems it doesn't work for other applications.
By design, Fiddler Everywhere will try to set itself as a system proxy and install the trust certificate in the operating system certificate manager. You can check if that is happening, and if not, export and install the Fiddler certificate manually for the operating system. Additionally, if Fiddler is not being set as a proxy for the operating system, that would mean that something prevents it (check if you have administrative rights to change the operating system proxy settings).
Ensure Fiddler Everywhere is set as a system proxy (when Capturing mode is on) and that the root certificate is installed. Then you will be able to capture traffic from all applications respecting the system proxy settings.
Seems here is a KB https://docs.telerik.com/fiddler-everywhere/get-started/quickstart-linux#installing-fiddler-everywhere-on-your-machine. I followed the steps to manually add the cert. However, it doesn't work.
Can you clarify what happens after you try to install the certificate manually? Additionally, you can send us the Fiddler Everywhere logs in our private support thread so that we can investigate further.
Hi Nick, I just enable capture https traffic and save. Then, I enabled the Live Traffic button. I found that the exported root CA certificate is a der format. So, I can see some messy code in /etc/ssl/certs/ca-certificates.crt. Is that normal after I run dpkg-reconfigure to install the exported .crt file. Is that normal?
After manually exporting and installing the Fiddler root certificate (FiddlerRootCertificate.crt) through dpkg-reconfigure tool you should see the confirmation like the one below
Once the certificate is successfully installed, you can restart Fiddler Everywhere and re-activate Live Traffic capturing.
Not sure what you mean by "I can see some messy code in /etc/ssl/certs/ca-certificates" - the content of a CRT is not meant to be in readable form
Here is the cert I exported from Fiddler.
I thinks this the der format. Is it normal?
Yes, that looks totally fine (CRT in binary).
Sorry, the crt file you sent is like a pem format instead of a der format. I can see the exported root ca file is a der format which seems to be error.
BTW, I finished the step as you said "Once the certificate is successfully installed, you can restart Fiddler Everywhere and re-activate Live Traffic capturing." But it doesn't work for me.
Do you guys have some instant talk tools like MS teams? Maybe we can have a talk about this problem.
I've just provided some additional instructions on providing the application logs in our private thread. Use the personal thread to send the log files as these might contain possibly sensitive information that is not safe for public sharing.