Can't connect with FiddlerCore

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stan.f...@gmail.com

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May 18, 2018, 9:47:13 PM5/18/18
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Hello, I've downloaded the FiddlerCore package and am trying to use the Demo program in the package. I've un-commented some existing code in the Demo program to view and modify some basic English words being returned within HTTP responses within websites. I've compiled the code using Visual Studio 2017. 

When I use this Demo program on simpler sites, even those with SSL/TLS, the words are modified on web pages as expected. However, when I try apparently more security-conscious websites I get the following message: 

This site uses HTTP Strict Transport Security (HSTS) to specify that Firefox may only connect to it securely. As a result, it is not possible to add an exception for this certificate.

Can someone please explain what's happening and is there something I can do in the Demo program (or to some FiddlerCore configuration perhaps?) to fix this?

If a code change is required, it would be awesome if some details about the code change (as opposed to a more abstract description) could be provided. :) I'm still learning FiddlerCore and would appreciate the functions, flags, etc. that may need to be changed. 

Thank you, regards,

Stan

EricLaw

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May 24, 2018, 9:34:57 AM5/24/18
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My guess is that you haven't yet configured Firefox to trust FiddlerCore's root certificate. You need to do that (instead of clicking through a certificate error page). If you're just playing around, you may find Chrome/IE/Edge easier because they use the system's default certificate store for which FiddlerCore has methods to update.


Jerry Lee Daniel

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Dec 18, 2023, 4:26:09 PM12/18/23
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