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 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?

I have a job which executes few webservices. When executed manually I keep the Fiddler app on and it captures the traffic.

But if I am scheduling the aforesaid job via Jenkins then is it feasible to capture the traffic? If yes then how?

Hello, I am IT for our compnay. We have a developer who is using Fiddler on a macOS Ventura with Temp admin rights. The rights need to be engaged and only last for 60 minutes.

The developer says that Fiddler requires full admin all the time for Fiddler to adjust system proxy settings at startup.

The developer says that the mac has lost all internet connectivity because Fiddler does not have access to manage proxy settings at startup. Is this true?

Please advise. Notes from developer below

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Subject: Mac lost internet connection with Fiddler

Hi Russell, a similar situation happened again. Steps: - run "Grant admin privileges 60 min" - run "Fiddler Everywhere" - change system proxy settings
Then, after about 5-7 minutes, i got the message "Grant admin privileges 60 minutes" has expired.
I can't get "Grant admin privileges for 60 minutes" in self service. I can't restore system proxy settings without administrator.
For now i have an internet connection through Chrome and i'm logged in. Please advice on system recovery

 

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Subject: Mac lost internet connection with Fiddler

Hi R,

 

The software we have used was Fiddler 

https://www.telerik.com/fiddler

 

It has an option to “Act as system proxy on startup”.

 

So when Fiddler is launched – it requires to enter admin’s password to modify global system proxy settings. Also when you finish work and close it – once again admin’s password is required to remove global proxy settings.

 

Regards,

R

I would like to suggest that Fiddler products be added to the Progress Control Panel to allow better management of updates and installations.

我尝试了所有方法，但无法解密他的HTTPS。请帮助我。

网址：https://visa.vfsglobal.com/chn/zh/pol/

请尝试使用 F5 刷新页面，它会提示：对不起，您已被阻止。

谢谢。

Hi Team,

My requirement is to capture the Mobile traffic through fiddler which is installed on windows. I am unable to configure and unable to download fiddler trusted root certificate. Can you please give us a solution as soon as possible.

Thanks & Regards,

Eesufvali

Hey,

 

so I followed the Guides so far, Installed the Cert to my IOS Device (as user Profile and trusted it)

However, every URL I open in the Browser nor App tells me:

ERR_SSL_VERSION_OR_CIPER_MISSMATCH.

Is there any step I missed? 

I am using Fiddler Classic strictly for its FiddlerScript capabilities, and I have just learned that the Progress team no longer have any plans to add this awesome functionality to Fiddler Everywhere. This is very sad news for me, as I feel that probably Fiddler's most appreciated feature is dropped all together. I have just installed the Everywhere version, checked out its Rules tab, but I am most positive that all those hard-coded rules will not even come close to the functionality and the simplicity provided by a scripting language. The Rules tab in Everywhere may be a more easier and intuitive option for most users, but this comes at the price of loosing the flexibility and the powerful tools that only a script can provide. The web is becoming more and more complex with each day, and in order for Fiddler to stay on top of it, I believe it should give its users access to the most powerful tools available. Employing scripting capabilities is certainly one of it, if not the best one! Why restrict that?!

I would like to take this opportunity to kindly ask the design team to re-evaluate this decision of dropping this future. It sets Fiddler apart from all the other software out there, and dropping it all together would be a major downgrade for Fiddler, in my opinion. Having a Rules tab for those in need of a quick set-up, and preserving the current scripting capabilities for those looking for powerful functionality seems like the best way to go for me. With these two foundations, I have no doubt Fiddler will continue to stay relevant and grow in the years ahead.

Anyhow, in case no re-evaluation will be made and approved, I would like to know if you have any plans of dropping support/updates for Fiddler Classic in the future. This would be a second blow to all the 10 year+ Fiddler users.

I hope both versions will be offered to us for many years to come, no matter how much the web will be changing. So, please confirm if we can at least rely on Fiddler Classic, as some believe it is only a matter of time until it will be deprecated (including me). For the time being, hopefully the plans to add support for HTTP/2 and TLS 1.3 will indeed materialize (for Fiddler Classic).

If others feel like me on this whole issue, please do comment. Thank you!

Alex

Im trying to capture SSL traffic from an application where i dont own the source code, but im forced to use it currently. Since i would love to see what its actually submitting to the webserver, i installed fiddler to capture the ssl traffic. However i quickly realized, that its not that easy since the application is using python request libary, which ignores the windows certificate store. Is there any way to decrypt the traffic , even if the application wont check the windows application store and im unable to change the code of the application? OS im running the application on is Windows 10 if that matters.