I'm configuring a printer to use Fiddler Classic as a remote proxy on a Windows 11 machine to monitor the printer communication with a cloud service.  The printer downloads a print document (several MB) then immediately returns an error to the cloud service saying there's some problem with the document.  It works fine with Fiddler Everywhere.  This will not be fixed on Classic?  Telerik says that Fiddler Classic is no longer being maintained yet new releases (including bug fixes) still seem to be coming out on a regular cadence.

I sned frequent requests between https://gym.whu.edu.cn/api/GSStadiums/GetAppointmentList?Version=2&SportsTypeId=21&AppointmentDate=2024-06-04 and https://gym.whu.edu.cn/api/GSStadiums/GetAppointmentList?Version=2&SportsTypeId=21&AppointmentDate=2024-06-05, I set up an auto-save to txt function,I can see the response in the fiddler,  in the firtst two request ,i can see the response in the txt,but in the following request,  the txt do not update,until over several times , i do it again ,it can be updated, I do want to know why this happen. Addly,if i do the request https://gym.whu.edu.cn/api/GSStadiums/GetAppointmentList?Version=2&SportsTypeId=21&AppointmentDate=2024-06-04  and https://gym.whu.edu.cn/api/GSStadiums/GetOftenList?Version=2 ,i can see the update in real time.
I want to add that I do the request by my manual click. In first way, i just click two buttons on the same interface. in the latter one, i keep opening the screen to return to the previous screen to do the request

Hey guys!

I noticed the Low-Level Capture Support for MacOS and I saw it planned for Windows as well.
So I am curious if there are already some details.

Out of curiosity, I think, we could look over to HTTP Debugger, which sadly was never updated anymore.
But HTTP Debugger captures every traffic on a Low-Level. 

I think modifying outgoing Requests is not possible there, but you can modify responses, which can bypass some limitations. 
(Like Cert verification on Fiddler)

So I am curious what the current plan could be.

I recently upgraded fiddler classic to the latest version, but after the upgrade, my extension file dll did not take effect. Its function is to decrypt traffic, which may be related to the upgrade of fiddler. I read the upgrade description and it seems to be a security-related issue. please help me.

I looked through the documentation and found nothing of value: https://docs.telerik.com/fiddler/extend-fiddler/extendwithdotnet

Fiddler classic the lastest version information:

5.0.20243.10853 [16/05/2024]
fixes:
 Check for updates fails in the beta channel.
 Update third party dependencies to mitigate potential security vulnerabilities.

How to set a dark theme on Fiddler Classic?

Hello, i have app using fiddler, and i have problem like in Subject. Proxy in windows settings turn on like normal but i can't see result of fiddler proxy. Im using windows 11. There's any way to fix that? Thanks! :) 

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!

 

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:

Is there currently a way to get the Filter back?

When I try to enable the System Capture it says: Capturing not enabled, please try again! 
I removed the Filter manually, but now I cannot add it back, I won't get asked. I checked if there is some local Storage, but couldn't find any.

Hi everyone,

I have an .net framework 4.7.2 C# WPF app running which also has a little .net 3.5 app inside it.

This is running 1500 computers in australia and has been for 18 months.

Today we started getting reports of computers having 'crashes'

Debugging has provided this info:

section: created rest options System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.

What we have now found out is that it is Windows 7 clients all being affected.

Importantly:

Postman and google chrome can access the api

JUST the .net seems ot be having issues.

After seeing this I have downlaoded fiddler (for first time) and we are seeing a handshake issue:

fiddler.network.https> HTTPS handshake to www.mydomain.com.au (for #710) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326


But then when i booted fiddler im also seeing the same issue:

[Fiddler] The connection to 'api.getfiddler.com' failed.  <br />System.Security.SecurityException Failed to negotiate HTTPS connection with server.fiddler.network.https&gt; HTTPS handshake to api.getfiddler.com (for #1) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. &lt; The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326                                       

 

 

So maybe the fiddler API is in fact having the same connection issue as I do, but maybe thats not really going to be noticed because its an update checker for their API but mine is my whole app??

 

Any ideas would be appreciated.