I'am trying to catch all traffic by using Fiddler API, but I get only  the 200 code result. I'm interesting in 101 code and websockets info, but I can't get them via API. When I use the UI Fiddler I can see websockets. Have any ideas why it happens?

I'm trying to debug a WPF client that talks to a WCF service, all running in Visual Studio. The service project (that holds the WCF services) is configured to use port 50000, and the WPF client has end points for that in the app.config.

I changed the WPF client to use localhost.fiddler:50000, which shows the requests in Fiddler, but I'd like to filter out everything else, so I only see these requests. However, I can't get the filtering to work.

If I enable filters, and set it to show only localhost.fiddler:50000 and localhost:50000, then when the WPF client makes a request, I see an entry for 
localhost:50000 in Fiddler, but this disappears as soon as the request has completed, so I can't inspect it.

I tried clearing the hosts filter, and telling it to show only intranet hosts, but this didn't show anything.

The weird thing is that if I set it to hide the most common hosts that I don't want (things like Skype, Teams, etc), then I get the same behaviour as above, ie the 
localhost:50000 requests appears briefly, and then disappears. The same happens when I try using a web browser, so it's not just Visual Studio and 
localhost:50000

Anyone know what's going on here? I'm using the latest version of Fidller on Win7 Pro 64-bit, with VS2019.

Please tell me how to realize the function of red box selection in fiddler core programming. Thank you!!!

Hi

I set a breakpoint after response and changed a value

then i hit the run to completion button an the changed value shows up in the browser but after a few seconds the old value displayed again

 

but there is no new traffic shown in fiddler

so why the change is not working?

I installed Fiddler (V4.6.0.2 - August 17 2015) on Windows 10 RTM (build 10240) x64 en-US.

Since then, Edge is no longer working (error "Hmm, we can't reach this page.") unless Fiddler is running.

Note that Firefox , Chrome and IE11 do not have this issue, they are OK when fiddler is NOT running.

I restarted the PC several times,the problem is still present.

I checked the ProxyServer key in HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings : the key is only there when fiddler is running.

Also I cannot sign in Windows Store or Groove Music unless Fiddler is running AND I've enabled the apps in  "App Container Loopback Exemption Utility" (WinConfig button).

Note #1: I have a warning  "Orphaned Exemption Record Found" when launching WinConfig, see attached screenshot.

Note #2: In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings, I have this key : _FiddlerDirectWrite = "BuggyWinShutdown at 01:07:59 2015-09-17". I don't know if this is normal.

Note #3 : I searched every location in registry with value "8888" ( fiddler proxy port) when Fiddler was running then I closed Fiddler and looked at the registry locations again.

I found 8888 in those 2 keys below, so I deleted the keys, restarted the computer but the issue is still there.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iphlpsvc\Parameters\ProxyMgr\{E6EFF353-402B-45F2-8D72-E8B7FA394DB5}]
"StaticProxy"="http=127.0.0.1:8888;https=127.0.0.1:8888"
"ProxyBypass"="<-loopback>"
"LastUseTime"=hex(b):8a,ce,43,c6,ba,f0,d0,01

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iphlpsvc\Parameters\ProxyMgr\{F9D45E1B-22AA-4CAA-BDA0-DA414B44C2A5}]
"StaticProxy"="http=127.0.0.1:8888;https=127.0.0.1:8888"
"ProxyBypass"="<-loopback>"
"LastUseTime"=hex(b):8a,ce,43,c6,ba,f0,d0,01

 

From HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList\Profiles, I can see that:

{E6EFF353-402B-45F2-8D72-E8B7FA394DB5} is "fortissl" : Fortinet SSL VPN that I use to connect to my company network.

{F9D45E1B-22AA-4CAA-BDA0-DA414B44C2A5} is "Network" : Ethernet connection

After I ran fiddler, the key {F9D45E1B-22AA-4CAA-BDA0-DA414B44C2A5} was re-created.

The other key {E6EFF353-402B-45F2-8D72-E8B7FA394DB5} would probably have been re-created as well if  VPN connection was established when I ran fiddler again.

Fortinet SSL VPN​ is working fine, I installed it right after Windows 10.

I had no issue  with Edge or Windows Store until I installed Fiddler 4.

 

hello
screenshot is attached

 

best regards, jan

I got a new machine and I added the code below according to this post. https://www.telerik.com/forums/remove-all-as-a-single-click-button-on-the-toolbar
Now after clicking on the BYE button, it clears the entries but Fiddler stops capturing anything from any site anymore. It only work once once I restart Fiddler.
It used to work on my old machine. I can't figure out what is different here.



 static function RemoveAll(s: Object, e: EventArgs)
    {
        FiddlerApplication.UI.lvSessions.Clear();                   
    }
    
    static function OnBoot() {
        
        try {
            for (var c in FiddlerApplication.UI.Controls)
            {
                if (c.GetType().Name == "ToolStrip")
                {
                    var ts: ToolStrip = c;
                    var tsi: ToolStripButton = new ToolStripButton("BYE!");
                    tsi.add_Click(RemoveAll)
                    ts.Items.Insert(0, tsi);
                }
            }
        } catch(e) { FiddlerApplication.Log.LogString(e); } 
        
    }

Hello,

Is there any way to decrypt TLS 1.3 yet? Some app's have started using TLS 1.3 only, so proxying my phone through Fiddler leaves me with undecryptable tunnels only.

 

An example of such a capture is attached.

 

Best regards,

Jack

Is there a way to have Fiddler not update the FiddlerScript rules file (CustomRules.js) in case the file contains any errors?

I use Fiddler to block some traffic, but in case the rules file contains even a small error, then Fiddler will drop all the rules inside the file and allow all traffic to pass.

The best solution would be to first check the validity of the file, and only update it in case it contains no error at all.

I woulnd't mind automating this through a Perl script, but I still need a way to interogate Fiddler over the validity of the file.

In case there is no easy way to do this, my only option would be to write a Perl script that will initiate a web connection that is supposed to be blocked by Fiddler. In case it is not blocked, I can only assume the rules file I had just updated right before initiating the connection contains an error. In this case, the Perl script would kill Fiddler, replace the rules file with the previous version, and restart Fiddler. Everything should not take more than just a few seconds. This way, even if the file is not valid, Fiddler will continue to apply the rules (and block the traffic I need to filter out). My only problem with this solution is that it will take me some time to code it. I am looking for a more elegant, quicker way to do it.

Thank you,

Alex

Hi guys

We use ninitepro which runs in the background and updates applications like Chrome/Adobe etc on our computers. Since it doesn't have an active window I can't see what it is connecting to via Fiddler and I'm trying to figure out how to enable scanning of background processes so Fiddler will pick it up.

Thanks

Gerry