Hi

Because of the vulnerability found in the Log4j logging framework, the IT department in my company wants to know, if Fiddler is using Log4j?

.NET application show error message below when I close Fidler program on Windows Server (Production Environment)

System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:8888

If I open the Fidler program again, this error will be lost. I think this error occurred because the Filder does not roll back some settings after closing. So system still routes to 127.0.0.1:8888.

But after closing Fidler program I have checked the Internet option. It rollbacks properly (Use proxy server is unchecked).

Have other configuration that Fidler have changed? Or how to reset the proxy setting?

Currently, I work around by opening Filder program always.

Please help to solve this problem.

Hi there,

I have a browser application running on localhost:4200 (Angular) which is calling API methods on a remote host.

Using fiddler 4 I am intercepting the response and adding a cookie. I am also logging all the headers.

static function OnPeekAtResponseHeaders(oSession: Session) {
    oSession.oResponse.headers.Add("Set-Cookie","Test=MyCustomValue;");
    FiddlerObject.log(oSession.oResponse.headers);
}

In the logs I can see my Test cookie. I can also see a variety of other Set-Cookie headers being returned by the remote host.

However, none of them are being set in the browser, including my test cookie.

I have tried with different combinations of Domain, Path, SameSite, Secure etc, including removing these altogether, and I cannot get any cookies to be stored by the browser.

Any idea?

Hi, I use some VPN (Windows 10 x64) that works trough TAP-Windows Adapter V9, is there any way to capture traffic from process that proxied by this VPN? I tried turn on VPN then run Fiddler and when I run my Firefox with VPN on it I have an error in my Firefox:

Secure Connection Failed 

The connection to the server was reset while the page was loading.

Also tried add VPN url to Fiddler options > Connections > Bypass Fiddler for URLs that starts with. Still same issue is up.

So can I fix this somehow?

Im using fiddler every where V2.2.0, and this problem has been quite a while.

It's normal when i capturing data such as html/json/text(or it just too small to be noticed), but when it comes to image/video, fiddler every where will use up all memory very quickly, even if i didn't capture that huge amount of data. And there is no way avoid this, setting rules or click remove all doesn't help, the only solution is restart fiddler, which is annoying because in nearly 99% memory used, it's no possiable to do anything unless you want to wait several minutes for a simple file save location selecte window to pop up.

I've tried using the Rules(Do not capture/Graceful close/ Non graceful close), and it doesn't help.

Here's a screenshot when i capture tiktok's video info, taffic useage is only 50MB~, and data includes video/image/protobuf/json/html. With a time passed by, and some anaylize of thoes text body(no image nor video body), memory use 32GB.

What the h?

I used the eval function in fiddlerscript to dynamically load code from the server when fiddler was opened.But when using the eval function to process JSON, the program throws an exception.code show as below：

 //Operating normally
if(oSession.uriContains('https://xxxxxx.com')){
                var responseStringOriginal =  oSession.GetResponseBodyAsString();
                var responseJSON = Fiddler.WebFormats.JSON.JsonDecode(responseStringOriginal);
                responseJSON.JSONObject['data']['data1']['data2'] = 22;
                responseJSON.JSONObject['data']['data1']['data3'] = 1;
                responseJSON.JSONObject['data']['data1']['data4'][0]['type'] = 2;
                responseJSON.JSONObject['data']['data1']['data5'][0]['type'] = 22;
                var responseStringDestinal = Fiddler.WebFormats.JSON.JsonEncode(responseJSON.JSONObject);
                oSession.utilSetResponseBody(responseStringDestinal);
            }

eval("if(oSession.uriContains('https://xxxxxx.com')){var responseStringOriginal=oSession.GetResponseBodyAsString();var responseJSON=Fiddler.WebFormats.JSON.JsonDecode(responseStringOriginal);responseJSON.JSONObject['data']['data1']['data2']=22;responseJSON.JSONObject['data']['data1']['data3']=1;responseJSON.JSONObject['data']['data1']['data4'][0]['type']=2;responseJSON.JSONObject['data']['data1']['data5'][0]['type']=22;var responseStringDestinal=Fiddler.WebFormats.JSON.JsonEncode(responseJSON.JSONObject);oSession.utilSetResponseBody(responseStringDestinal)}")

（It says that Hashtable cannot cast to StackFrame）

Thanks for help.

I have Fiddler up and running on box A.  I can see all traffic from my local machine and my autoresponders are working as expected.

On my Android cell phone I have set up the network to use box A as proxy.  The pages are being rendered in the Android browser as expected and autoresponders are giving the correct data as expected, but none of the traffic is showing in the Fiddler UI.

Any idea?

My enviroment:

I run my connection through a barracuda web security gateway proxy that uses a pac file to connect

Issue.

I was running into an issue with google earth pro and was attempting to use fiddler to troubleshoot the issue. I installed fiddler without admin permissions. Google earth pro streetview fails to download images due to 407 error (Web page that renders image gives a failed to pass or parse credentials from proxy.)

The issue I am running into is when I run fiddler it "fixes" the issue without indication of where the issue came from. I uninstall fiddler and the "fix" remains even after removing google earth pro registry files tmp files and cached files, something on my system changed when installing fiddler that prevents the images in google earth pro from using my pac file when connecting. I cant seem to find out what change was made to reverse it even after an uninstall of fiddler. Any help or information regarding what system changes are made with the fiddler installer would be greatly appreciated.

Thank you,

Patrick