Hello, 

I just installed Fiddler 4 on Windows 8 and when I run it I get a NullReferenceException at Fiddler.frmViewer.DoPostInitPreLoad(). There is a screen shot attached. I've been using Fiddler for years and this is the first time I've ever had a problem like this. I Googled the error but nothing seems to match. I'm really not sure how to proceed.

Any thoughts? Suggestions? 

Thanks, 

Mike

Hello,

Anyone had recent problems with a virus on fiddler 4.4.9.0?  I have been using fiddler as a proxy server to monitor web service traffic from several embedded devices that talk to my web service.  Recently I have been getting a flood of http packets from some unknown Chinese ip address.  I verified that somehow fiddler is the culprit by running wireshark and fiddler simultaneously.  When fiddler is running I start to get one or two Chinese ip address starting to hit my server.  Over time ( a few minutes ) it becomes a flood of http packets.  I record the chinese ip addresses with wireshark.  I then set the display filter in wireshark to trigger whenever one of these Chinese ip addresses hits the server.  When I run fiddler I get a flood of hits on wireshark.  When I shut down fiddler I get virtually no hits on wireshark.  The problem started a couple of weeks ago around the time when I upgraded fiddler 4.4.9.0.  However, I cannot be sure that the problem is due to 4.4.9.0.  I checked the location of the ip addresses using one of the popular web ip geolocators.  All them are originating from Shijianzhuang, Hebei, China.  The isp is China Unicom in Hebei.  Anyone else having the same problem?  Any fixes?  I will uninstall and re-download fiddler later today and see if the problem persists.

Best Regards,
Steve Mansfield 

I have been using 4.4.8 for a bit now.  I didn't do any config changes on it at all, has been working great.

I am debugging an app running on my local IIS set to run in SSL.  It makes calls out to web services on other machine and I use Fiddler to look at the SOAP in and out.

Today I saw the prompt so downloaded and installed 4.4.9.1 (by the way Symantic flagged it as being a possible threat, but I installed the file from Telerik.com)

After installing it all traffic for my application was showing as tunnel to... and nothing else. I searched around and found I needed to set it to decrypt the SSL, but I didn't have to do this with 4.4.8.

I can see the traffic for my app now, but I do not see the calls to the webservice.  The calls still happen, there's just nothing shown on Fiddler.

Again, this all just worked with 4.4.8, I had not needed to do any config changes.

I uninstalled 4.4.9.1 and reinstalled 4.4.8, but still the same.

Were there config changes made duning the install to 4.4.9.1?  How can I undo them so that I can see the SOAP calls again?

Hello,
Is it possible to install a official certificate (like a purshased VeriSign certificate) instead of the auto generated certifcate by fiddler ?
Thanks
Pascal

Hi! I've made a program on C# and it's work perfectly but stops on POST method to the page. When I use Fiddler as a proxy there is no errors. So I would like to know, what does fiddler to with my POST query so it works? What does Fiddler do with it.

Hi,
I'm pretty new to fiddler so I beg your pardon if I'm posting a silly (or well-known) question... but I searched cygWing and wget keywords without success

I tried to use Fiddler in a test environment, in order to capture Http traffic from a REST web-service application.
Test stimulus comes from a cygWin shell running a wget GET & POST requests, on a Win7 PC. The response is a plain json text.

Fiddler traces http traffic when I issue GET requests from Firefox and from Fiddler itself, but nothing gets tracked when I use Fiddler
with my test suites based on cygWin + wget.

In first place I'd like to know if I'm trying something out of the scope of Fiddler (e.g: because of cygWing+wget implementation, or some other reason).
If you tell me it should work, I'll invest in studying in more depth the topic and I'll find how to do....
....although any quick additional suggestion will  be welcome !

thanks in advance

So I have recently been struggling to get my .NET client working with mutual authentication. In the process of debugging with Fiddler, I noticed that if I make my public cert available to Fiddler, it adds it to the response I get from the server, and I am able to successfully complete my next request(instead of HTTP 401).

So my question is, what is the purpose of this functionality? Has someone experienced something similar?

The latest (and previous versions) of Fidler2setup.exe /S (for Silent) fail to install with Return Code 4444.

If there is a log I don't know where to find it and as NSIS is used there is no logging command line switch (a good enough reason to switch I'd have thought). A windows installer version would be much better (you could look at my free MAKEMSI tool, for easy command line msi building).

The required dot net version is installed:

ASoft .NET Version Detector Report
Download latest version at http://www.asoft.be

==== INFO ====
Created :2014/07/02 - 08:08:57
Computer:XD77038345AA0C

==== FOLDERS ====
<32Bit>
2.0.50727.42
  ->C:\WINNT\Microsoft.NET\Framework\v2.0.50727

==== Installed .NET Frameworks ====
.NET FW 2.0
==== END REPORT ====

Any ideas? Any other ways of installing it? I don't want to manually do it, has to be automated.

Hello,

I too am having issues with Fiddler, I've been using it for years as well and have downloaded the latest version (although the issue showed up earlier today in the previous version I had installed). I can't say when this started - other than most probably sometime in the last week, I tend to use Fiddler a lot but just noticed it today.

The symptoms are as follows...

If I turn capture on, all HTTP requests fail. If I try in Chrome, I can view more error details and see ERR_CONNECTION_RESET at the bottom of the screen. 

I have "Use Filters" unchecked.
I have clicked "Troubleshoot Filters" but my requests are not showing up in Fiddler.
I have tried both http://localhost:8888 and http://ipv4.fiddler:8888 when Fiddler is capturing and I receive nothing in Fiddler, and an ERR_CONNECTION_RESET message when I drill down into the error shown by Chrome.
I have checked proxy information, it is being set to 127.0.0.1:8888 as expected for both Http and Https when capturing. When not capturing the details in WinInet are blank (no proxy server).
I usually see a raft of logs when I have Fiddler enabled from my Win8 apps, now it's all completely clear - which leads me to believe that it's a system wide issue. I've reset the Win8 config but that made no difference.
I have tried Chrome, IE and FF but all exhibit the same behaviour.
The version I am running is v4.4.8.4, 10th June 2014.
Looking at my Firewall (Windows Firewall only) I see "FiddlerProxy" enabled with both Private and Public checked.
When running a new instance I see the following in the log...

14:24:45:8803 Fiddler Running...
14:24:45:9143 Windows 8+ AppContainer isolation feature detected.

I am on Windows 8.1.

Any suggestions you have will be greatly appreciated!

Cheers,

Morgan

I'd like to see GET arguments of a URL, not in the URL itself but parsed. Does Fiddler show those?