When accessing the nature website via fiddler, if you check Decrypt HTTPS traffic, error 403 forbidden will appear, unchecked resolve https can be accessed normally. As you can see in the picture below:

hi there

on windows 2022 server when i close fiddler or stop capture traffic

running apps can nor connect tls 1.2

i always get errors for service connecting until start capturing.

What should I do to make the system work properly when the program is closed?

 

Thaks for your help :)

I try many library, last library I try was global-tunnel-ng, but still have no result. Usually I use fiddler to trace various request, my Fiddler listen port 8888, therefore I try to use

I expected to see all request on Fiddler, but there are nothing any request on Fiddler panel. 'localhost' and '127.0.0.1' as ProxyURL also don't working. What I doing wrong?

I try many library, last library I try was global-tunnel-ng, but still have no result. Usually I use fiddler to trace various request, my Fiddler listen port 8888, therefore I try to use

 

  var globalTunnel = require('global-tunnel-ng');
  globalTunnel.initialize({
    host: 'ipv4.fiddler',
    port: 8888,
  });

  // my various request to Google, to AWS and more

  globalTunnel.end()
I expected to see all request on Fiddler, but there are nothing any request on Fiddler panel. 'localhost' and '127.0.0.1' as ProxyURL also 
don't working. What I doing wrong?
 

Hi

I am using Fiddler Classic v.5.0.20242.10753 for .NET 4.6.2 64-bit on Windows Server 2012R2 (don't ask!)

I am also using FiddlerScript in C# mode.  My use case is that I am trying to create a temporary fix for a legacy service that is responding with incorrectly derived values in an XML payload.  I can force all clients of this service to access it via Fiddler as a proxy, and I wanted to use FiddlerScript to modify the response to correct some of the data, as it can be derived from other parts of the response.

I did a very very rough PoC by catching the specific calls in OnBeforeResponse and making an arbitrary change.  What I have then tried to do is use the System.XML XmlDocument object, pass it the response body when instantiating, and working from there.

THE PROBLEM:  I have added "using System.XML;" to the script.  I have also added "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\System.XML.dll" to the References field in Fiddler under Tools -> Options -> Scripting and restarted Fiddler Classic.  However, when saving the script, I get an error "The type or namespace name 'XML' does not exist in the namespace 'System' (are you missing an assembly reference?)"

I have tried just about everything I can think of to make that reference:
 - adding directly to the dll in the Windows dir
 - copying the dll(s) to the same DIR as the Fiddler.exe (as suggested in your docs)
 - adding the XML dlls to the GAC

Nothing I do seems to solve this problem.  I thought it might be a .NET version issue, but I have 4.6.2 installed.

How do I properly reference other .NET assemblies that I want to use in script? 

Thanks,
Steve.

After update updating Edge browser to version 124.0.2478.51，when access website I get  "Your connection is not private" 

I have configured Windows to trust Fiddler's root certificate.

I set fiddler " !listen 8889 *.acs.org " and set " fiddler.network.https.SetCNFromSNI true"  It works well  before update edge browser.

After update edge when i access pubs.acs.org it is ok.

but when i access pubs.rsc.org i get   "Your connection is not private" 

 I think this is because someing make fiddler  cannot automatically match certificates .

Please help me fix it ,thanks so much!

 

I thought maybe I was imagining this, but I can consistently reproduce it. Problem started with Fiddler Classic, and I then tried Fiddler Everywhere only to see the same behavior:

My dev/debugging environment consists of MS Visual Studio, Postman, and Fiddler running on Windows 10. I always have MS Outlook, MS Teams, and SSMS running as well. I run both Visual Studio, Postman, and Fiddler as Administrator, though I've tried running them in normal mode as part of debugging this problem. It makes no difference.

Any time I start Fiddler, within approximately 15 minutes, Teams is the first app to go down... it suddenly reports "no internet connection" and I can't send or receive messages.

Shortly thereafter, Outlook will start throwing up "invalid security certificate" dialogues. Email send/receive is no longer possible after this point... The Outlook Icon in my taskbar shows a yellow triangle with a black exclamation mark.

Next to go is the ability to make https connections through, for example, Chrome or Edge.  I see errors such as the attached.

Has anyone else experienced this behavior? I've tested extensively making sure just the apps I've mentioned earlier were running. I can run for 24, 48, or more hours without the problem occurring. But if I fire up Fiddler (either Classic or Everywhere), 100% of the time, the networking issues occur. Always.

Any thoughts on what might be going on here? My assumption is that Fiddler is trying to be a proxy for everything on my machine, and it just can't do it for <reasons>. If I remember correctly I can manually tell Fiddler NOT to proxy for certain apps, but this seems tedious. I'm especially worried to suddenly see https disabled for Chrome or Edge, as the Visual Studio applications I'm debugging are APIs that use https...

 

 

I'm having this issue where fiddler will only capture traffic coming from 127.0.0.1:8888, any other traffic is CONNECT, I've tried everything to get it to capture normal.

Hello, when I examine facebook.com traffic, unfortunately fiddler cannot decrypt HTTPS traffic. Even though I click on it many times, I can't get any results. I don't have problems with other similar applications, but I have problems with Fiddler. How can I solve this?

 

1) Fiddler didn't hint for most top-level user class name anymore. For example, the following code:

• If I type code at **, it'll hint all system class without Xyz1 but it shows Xyz2.
• If I type "Xyz1." then it hint "Xyz3" so it seems to see fields/methods inside properly.

I use Fiddler in another PC (PC2) which report the exact same version (and editor's version), it hints my class properly.
*PC2 that works well has a bit lower WinNT part "WinNT 10.0.18363.0"

class Xyz1 { //Try both public, class
public static class Xyz3 {

}
}
class Handlers
{
static class Xyz2 {

}
public static function xx2(){
**
}
}

The scenario:

"Before this", I think Fiddler hint it in current PC (PC1) too. But it's abruptly missing so I try typing the new class. It hints the new class but not for the class I'll use. So I was dumbfounded and reset the script (delete the file) and retest. Because I know some pattern of code may break Fiddler format. Then "Handlers" is not in the list so I'm sure it's not about the format. I want to confirm that it normally hint top-level class name so I check it in my PC2, and it did. Then I completely uninstall-reinstall Fiddler in PC1. It fails it list any user class. I also try to swap the script to test between PC1 and PC2. PC1 always not work and PC2 always work. *I did not try to reinstall on PC2 though because it's heavily used. But it has the exact same version.

2) Script editor from "Customize Rules..." menu change after close and open it for the 2nd time - even without restart Fiddler Classic. Folding feature is missing and comment will be green instead of gray as after fresh install Fiddler Classic. I usually use this variant though, maybe because the gray comment version is found only once after fresh install. Embedded editor in tab is green with folding though. But problem 1) hint never work anywhere.