Troubleshoot web browser connectivity or errors using HTTP Fiddler / HTTP Header

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Article ID: 170523

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Updated On:

Products

Web Security Service - WSS

Issue/Introduction

You are having unexpected results with a web page, such as:
  • Some areas or images do not load or appear to be blocked.
  • A website may be unreachable from one data center but not another or for one user but not another.
 
You need to troubleshoot web browser connectivity or errors:
  • Client and/or TSE needs information on HTTP(s) traffic between a computer and the internet.
  • Gather data for troubleshooting and/or escalating connectivity in web browsers.
Please download fiddler4 (Free web debugging tool) from below website, and install it to start capture.
https://www.telerik.com/download/fiddler/fiddler4

 

 

 

Cause

Supported Technologies

Any Browser
Telerik Fiddler web debugging proxy helps you record, inspect and debug traffic from any browser.


Any System

Debug web traffic from any Windows-based PC, Mac or Linux system and mobile devices alike.
 
Debug traffic from PC, Mac or Linux systems and mobile devices. Ensure the proper cookies, headers and cache directives are transferred between the client and server. Supports any framework, including .NET, Java, Ruby, etc.
Fiddler is a free web debugging proxy which logs all HTTP(s) traffic between your computer and the Internet. Use it to debug traffic from virtually any application that supports a proxy like IE, Chrome, Safari, Firefox, Opera and more.
 
 

 

Environment

Web pages are failing to connect, getting errors, or intermittent disruptions.  

 




 

Resolution

Getting Started with Fiddler
https://youtu.be/gujBKFGwjd4

If HTTPS decryption is required:
Fiddler can decrypt HTTPS sessions by re-signing traffic using self-generated certificates.

Go to Menu > Tools > Fiddler options
Select HTTPS tab
Enable "Capture HTTPS CONNECTs and Decrypt HTTPS traffic"
IMPORTANT: Trust the FiddlerRoot certificate TEMPORARY only for testing. DO_NOT_TRUST_FiddlerRoot certificate permanently.
 
Capture Web Traffic
 
1. Open preferred web browser.
2. In Fiddler, click the File menu.                                                
3. Ensure Capture Traffic is enabled.
 
Capture Traffic
 
4. Reproduce the issue, on the machine, and then start the Fiddler trace.
5. Once completed collect the client trace log and save the Fiddler trace and exit

Captured web traffic sessions appear in the Sessions List.
 
 
Sessions List

 
6. Once completed save the Fiddler trace log.
 
7. To save, select File> Save As>All Sessions
 


 
8. Upload log to your case.
 


 

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