I use fiddler to review the http and https communications from our application. We have a websocket implementation connected to a phoenix/elixir server using the ws prefix. So our url looks like ws://{ip}:4000/socket/websocket. None of the communications from our application to this end point are visible in Fiddler. I can see any and all http and https traffic we're doing, but not the websocket calls. The websocket connections are working and the app is sending and receiving messages correctly, but I'd like to be able to see the messages to monitor this part of the application. Any idea how to make the ws prefix visibile?

starting Fiddler stops a running docker process.

stopping Fiddler shuts docker demon down completely.

docker version: 17.09.0-ce

Mono version: 5.4.201

Fiddler version: Beta downloaded 31-Oct-2017

Macos version: Sierra 10.12.6

Workaround: start docker process after starting Fiddler

Let me know if there's anything I can do to support investigation.

I used to change Fiddler script to add the automatic authentication to make console based applications work with NTLM authentication, however my company has moved from TMG to McAfee Web Gateway and now the code below is not working. 

 

oSession["X-AutoAuth"] = "domain\user:mypass";

 

CONNECT www.telerik.com:443 HTTP/1.1
Host: www.telerik.com:443
User-Agent: Fiddler/4.6.2.32002 (.NET 4.6.2; WinNT 10.0.14393.0; en-US; 4xAMD64; Auto Update; Full Instance)
Proxy-Authorization: Negotiate TlRMTVNTUAABAAAAl4II4gAAAAAAAAAAAAAAAAAAAAAKADk4AAAADw==


HTTP/1.1 407 authenticationrequired
Via: 1.1 172.99.71.201 (McAfee Web Gateway 7.6.1.1.0.21006)
Date: Fri, 30 Sep 2016 18:11:09 GMT
Content-Type: text/html
Cache-Control: no-cache
Content-Length: 3007
Proxy-Connection: Keep-Alive
Proxy-Authenticate: NTLM
Proxy-Support: Session-Based-Authentication

Can you help me?

Hi there, I'm trying to capture traffic on a Windows 10 from the universal mail app. I followed the app container procedure however when I start capturing a press the sync button in the mail app, the app just keeps showing the loading animation over and over. As soon as I close fiddler the mail app manages to sync. Can anyone confirm this behaviour and perhaps have a solution? Thanks.

Just installed Fiddler for Linux, seems to capture traffic just fine from FireFox, but not Chromium? Any ideas why?

I have installed the full version of dot net 4 and fiddler 4 to debug a website on a windows xp pc. But when I open firefox and start fiddler I get the following error in the browser
[Fiddler] The connection to 'fiddler2.com' failed.
Error: InvalidArgument (0x2726).
System.Net.Sockets.SocketException
An invalid argument was supplied 198.61.131.236:80

I've followed the documentation on the telerik website and googled for a solution but can't find anything.
Can anybody help?

I have one client and 3 server running. suppose client is running on
http://localhost:8000
and other three servers are running at:
http://localhost:8001 ----->server1
http://localhost:8002 ------>server2
http://localhost:8003 ---------->server3
there is communication between these server also. My question is:
1.Can Fiddler be placed “in front of” the server2 by advertising its IP instead of the actual server2. if yes, then how?
2.When Fiddler receives a POST request from client, i want to modify the message and then forward it to the server2. How can this be achieved?
3.Similarly, when the response comes back from the server2, modify it as needed before returning it to the client.

Hi - I have an application (.exe) that was written in Python.  It makes a HTTPS call out and data is returned in JSON.  With Fiddler running, I can run the program, it makes 2 web calls and bring back data.

As soon as I enable Fiddler for HTTPS and Decryption, the program won't return data.  

I enabled the CERT from Fiddler and made sure the proxy was correct in my LAN settings.  Any ideas?  (Windows 10)

Basically lets say you replay something 500 times, how can you control the speed instead of it being 1 millisecond or what ever the default speed is.

After last update, fiddler didn't wor. Kill Internet Connection and thats all.