I am using windows 10, and outlook 2016.  I installed Fiddler and configured it for WinHttp and SSL and everything worked fine.  My internet settings are set to automatically detect proxy settings and I followed the documented settings for WinHttp configuration ("netsh winhttp set proxy netsh winhttp set proxy 127.0.0.1:8888 "<-loopback>").  As I mentioned, I was able to see all traffic.  The first strange thing that happened is that Outlook stopped working unless Fiddler was running.  If Fiddler was not running, I get just get disconnected message from Outlook.  I changed the WinHttp settings back, (netsh winhttp set proxy default) but the issue did not go away.  I tried changing the Fiddler SSL settings to just connect for browsers, but no change.  I tried to not connect to SSL at all, and unchecked the box which started fiddler as a proxy, but still no change.  I uninstalled Fiddler, but Outlook is still broken.  I went in and deleted the Fiddler cert but still nothing.  I am sure this is not a coincidence as I previously encountered this and rebuilt the system.  This is the second time I have seen this same behavior, only after installing and using Fiddler.  Any ideas how to fix it?

Hi,

First, I have to say this is a great tool and I'm very impressed.  I managed to get everything set up to intercept SSL traffic from a Symbian device, through my local hotspot, and redirected to another server (still over HTTPS).  FYI, this is to reroute traffic to a test environment using a device that, unfortunately, has only production URLs burned in (don't get me started on that!).

On the device, I have three options to test my setup:  Opera Mini, the native browser, and the application I wish to test.  If I access my target URL via OM, everything works fine.  If I access it via the native browser or the application, the connection is closed immediately after the SYN, SYN/ACK, ACK exchange.  At first I thought that perhaps the device had app-level configurations for the certificates, but they all have the same settings.  Besides, the certificate hasn't yet been exchanged between the two endpoints.

Looking at Fiddler, the only difference I can see is that OM makes an HTTP/1.0 request, and the other two make an HTTP/1.1 request.  Looking at a tcpdump, one difference I noticed was in the TCP options, where in the successful request the TCP timestamps (tsval and tsecr) are specified and they are absent in the request that fails.  I wonder if the client might try to use those when performing the SSL handshake and, if they are absent, simply aborts?

Unfortunately, I can't see exactly what is sent from the device to Fiddler because I'm on Windows 7 using a local hotspot with Microsoft's virtual wifi miniport adapter.  Unless I'm mistaken, Wireshark won't capture on that interface.

Any ideas would be most welcome.

Thanks,

Sebastien

I know that there's a feature where you can save everything by going to View -> Tabs -> AutoSave in fiddler, but is there anyway to do that in plain text? It would be really convenient if I could do that.

 

Thanks in advance!

The server we use requires <proxy usesystemdefault="False" proxyaddress="http://10.50.131.50:8080"/> for the WebRequest to reach the 3rd party site I'm trying to get files pulled down from.  On that server Fiddler2 will capture traffic if I use a browser to pull the files, but if I use my application it will not.  I am a Fiddler2 novice, BTW, so I've just tried what looked relevant which is in Tools/Fiddler Options I put 8080 for the Fiddler listens on port on the Connections tab and I also tried on the Gateway tab setting it to Manual proxy https://10.50.131.50:8080 like the proxy setting in my app.config file.  Neither of those do it.  I found that if I remove the proxy setting from my app.config file then Fiddler2 sees the calls my application makes, however, as stated above, the calls do not reach the website so that doesn't help much.

Being a newbie I have reached the limit of things I can see to try ... can anybody help?

Consider a web server hosting a site (mysite.com) for which both HTTP and HTTPS are allowed. When the client browses to HTTP, he's automatically redirected to HTTPS.

I'm seeing different behavior based on whether Clear WinINET cache is used or not. On a regular capture session, following a request sent from a browser for http://mysite.com Fiddler (v4.6.2.3) shows: 200 | HTTP | Tunnel to | mysite.com:443. Next frame is 200 | HTTPS | mysite.com | / . It's like the HTTP request never exists - it's not even visible on a Wireshark capture. For the same exact request, but after clearing the WinINET cache, the output is different, with the first frame, as expected, being: 302 | HTTP | dialin.temenos.com | / . Clear the temporary internet files in IE (not Edge) doesn't result in any different outcome. It seems it's only Fiddler's magic function that does the trick.

Any idea if the WinINET cache can be cleared without using Fiddler, ideally from a browser (either IE / Chrome / etc) ?

Code:
namespace ClassLibrary2
{
    public class Class1 : IAutoTamper, IFiddlerExtension
    {
        private UI ui;
        private bool bLoaded;
        ...
        public Class1() {
            
            bLoaded= false;
        }
        public void OnLoad()
        {
            this.ui = new UI();           
            this.bLoaded = true;


        }
        public void OnBeforeUnload()
        {  /*noop*/

        }

        public void AutoTamperRequestBefore(Session oSession)
        {  /*noop*/

            if (bLoaded && url.Contains(oSession.hostname)) {
              .....
            }

        }
        public void AutoTamperRequestAfter(Session oSession)
        {

        }
        public void AutoTamperResponseBefore(Session oSession)
        {          
             .....
        }
        public void AutoTamperResponseAfter(Session oSession)
        { /* noop */
            

        }
        public void OnBeforeReturningError(Session oSession) { /* noop */ }


    }
}

Error:
---------------------------
Uncaught Exception in Session #1
---------------------------
Fiddler has encountered an unexpected problem. If you believe this is a bug in Fiddler, please copy this message by hitting CTRL+C, and submit a bug report using the Help | Send Feedback menu.

未将对象引用设置到对象的实例。

Type: System.NullReferenceException
Source: ClassLibrary2
   在 ClassLibrary2.Class1.AutoTamperRequestBefore(Session oSession)

   在 Fiddler.FiddlerExtensions.DoAutoTamperRequestBefore(Session oSession)

   在 Fiddler.Session._executeObtainRequest()

   在 Fiddler.Session.RunStateMachine()

   在 Fiddler.Session.Execute(Object objThreadState)


Fiddler v4.6.2.2 (x64 AMD64) [.NET 4.0.30319.42000 on Microsoft Windows NT 10.0.10586.0] 
---------------------------
确定   
---------------------------

Code:

namespace ClassLibrary2
{
    public class Class1 : IAutoTamper, IFiddlerExtension
    {
        private UI ui;
        private bool bLoaded;
        ...
        public Class1() {
            
            bLoaded= false;
        }
        public void OnLoad()
        {
            this.ui = new UI();           
            this.bLoaded = true;


        }
        public void OnBeforeUnload()
        {  /*noop*/

        }

        public void AutoTamperRequestBefore(Session oSession)
        {  /*noop*/

            if (bLoaded && url.Contains(oSession.hostname)) {
              .....
            }

        }
        public void AutoTamperRequestAfter(Session oSession)
        {

        }
        public void AutoTamperResponseBefore(Session oSession)
        {          
             .....
        }
        public void AutoTamperResponseAfter(Session oSession)
        { /* noop */
            

        }
        public void OnBeforeReturningError(Session oSession) { /* noop */ }


    }
}

 

Error:

---------------------------
Uncaught Exception in Session #1
---------------------------
Fiddler has encountered an unexpected problem. If you believe this is a bug in Fiddler, please copy this message by hitting CTRL+C, and submit a bug report using the Help | Send Feedback menu.

未将对象引用设置到对象的实例。

Type: System.NullReferenceException
Source: ClassLibrary2
   在 ClassLibrary2.Class1.AutoTamperRequestBefore(Session oSession)

   在 Fiddler.FiddlerExtensions.DoAutoTamperRequestBefore(Session oSession)

   在 Fiddler.Session._executeObtainRequest()

   在 Fiddler.Session.RunStateMachine()

   在 Fiddler.Session.Execute(Object objThreadState)


Fiddler v4.6.2.2 (x64 AMD64) [.NET 4.0.30319.42000 on Microsoft Windows NT 10.0.10586.0] 
---------------------------
确定   
---------------------------

Code:

namespace ClassLibrary2
{
    public class Class1 : IAutoTamper, IFiddlerExtension
    {
        private UI ui;
        private bool bLoaded;
        ...
        public Class1() {
            
            bLoaded= false;
        }
        public void OnLoad()
        {
            this.ui = new UI();           
            this.bLoaded = true;


        }
        public void OnBeforeUnload()
        {  /*noop*/

        }

        public void AutoTamperRequestBefore(Session oSession)
        {  /*noop*/

            if (bLoaded && url.Contains(oSession.hostname)) {
              .....
            }

        }
        public void AutoTamperRequestAfter(Session oSession)
        {

        }
        public void AutoTamperResponseBefore(Session oSession)
        {          
             .....
        }
        public void AutoTamperResponseAfter(Session oSession)
        { /* noop */
            

        }
        public void OnBeforeReturningError(Session oSession) { /* noop */ }


    }
}

 

Error:

---------------------------
Uncaught Exception in Session #1
---------------------------
Fiddler has encountered an unexpected problem. If you believe this is a bug in Fiddler, please copy this message by hitting CTRL+C, and submit a bug report using the Help | Send Feedback menu.

未将对象引用设置到对象的实例。

Type: System.NullReferenceException
Source: ClassLibrary2
   在 ClassLibrary2.Class1.AutoTamperRequestBefore(Session oSession)

   在 Fiddler.FiddlerExtensions.DoAutoTamperRequestBefore(Session oSession)

   在 Fiddler.Session._executeObtainRequest()

   在 Fiddler.Session.RunStateMachine()

   在 Fiddler.Session.Execute(Object objThreadState)


Fiddler v4.6.2.2 (x64 AMD64) [.NET 4.0.30319.42000 on Microsoft Windows NT 10.0.10586.0] 
---------------------------
确定   
---------------------------

---------------------------
Awww, Fiddlesticks!
---------------------------
Fiddler has encountered an unexpected problem. If you believe this is a bug in Fiddler, please copy this message by hitting CTRL+C, and submit a bug report at http://www.telerik.com/forums/fiddler.
VersionCheckFailed: Server Response Code = 307
Type: System.IO.InvalidDataException
Source: Fiddler
   at Fiddler.Updater.GetLatestVersion(Boolean includeBetaVersions, Boolean isEmergencyCall)
   at Fiddler.Updater.EmergencyUpdateCheck(Object stateInfo)
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

Fiddler v4.6.2.3 (x86 x86) [.NET 4.0.30319.42000 on Microsoft Windows NT 6.1.7601 Service Pack 1]
---------------------------
OK  
---------------------------

I have just installed FIDDLER v4.6 (under C:\Program Files (x86)\Fiddler2.) When starting up it gives below message. Rather than add relevant permissions to that network path, I'd rather re-config so the path is on local drive. However, I can't find a relevant config under Preferences tab; is it configured within REGEDIT, i.e. to define startup and/or script paths ?? Thanks in anticipation. 

 

Fiddler has encountered an unexpected problem. If you believe this is a bug in Fiddler, please copy this message by hitting CTRL+C, and submit a bug report at http://www.telerik.com/forums/fiddler.
Access to the path '<network_path>\Fiddler2\Captures\Requests\' is denied.
Type: System.UnauthorizedAccessException
Source: mscorlib
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.Directory.InternalCreateDirectory(String fullPath, String path, Object dirSecurityObj, Boolean checkHost)
   at System.IO.Directory.InternalCreateDirectoryHelper(String path, Boolean checkHost)
   at Fiddler.CONFIG.EnsureFoldersExist()

Fiddler v4.6.2.3 (x64 AMD64) [.NET 4.0.30319.34209 on Microsoft Windows NT 6.3.9600.0]