Fiddler does not work when WSSA is installed

Products

• Cloud Secure Web Gateway - Cloud SWG

Issue/Introduction

Trying to use Fiddler to capture traffic with WSSA enabled, but it is not able to see any traffic.

Environment

Cloud Secure Web Gateway

Cause

Fiddler and WSSA are both competing for the role of system proxy and use of the loopback traffic and that is what's causing Fiddler to not function.

This could happen with any other application also using the loopback address to act as a proxy.

Resolution

To allow WSSA and Fiddler to work simultaneously, you will need to add the loopback address to the bypass list in the Cloud SWG portal.

1. Navigate to Connectivity > Under Setup and Configuration > Select Bypassed Traffic
2. Under Bypassed IPs/Subnets add the address 127.0.0.1

Note: Adding 127.0.0.1 to the bypass list will cause user traffic to be sent through the system's 'non-interactive' tunnel, so user-based or group-based rules will not be enforced. Therefore, this should only be a temporary solution.
Note: Adding a new entry to the bypass list will cause all WSSA clients to reconnect to WSS.