Configuring Fiddler Everywhere alongside Cisco AnyConnect

Environment

Product Fiddler Everywhere
Product Version 1.1.0 and above
3rd-party tool Cisco AnyConnect

Description

The article covers the specific configuration needed to use Fiddler Everywhere with VPN software like Cisco AnyConnect.

Prerequisites

Configuration Steps

The steps' executing order is crucial for the proper setup of the Cisco AnyConnect alongside Fiddler Everywhere.

  1. Make sure your Cisco AnyConnect client is disconnected.

  2. Start Fiddler Everywhere and turn on the Capturing mode.

  3. Open the Settings > HTTP menu, add the trust certificate and check the Capture HTTPS traffic box.

  4. Open the Settings > Connections menu and in Bypass Fiddler for URLs that starts with: add the VPN addresses of your VPN servers. Press the Save button to preserve the bypass list.

    Bypassing VPN addresses

    As a separator for multiple addresses in the bypass list, you can use a comma, semicolon, new line, and white space. All separators will be converted to the OS supported separator after saving the values. Once the addresses in Bypass Fiddler for URLs that starts with: are set, the values are persisted and used by Fiddler Everywhere to set the OS’s bypass list (for example, you can open the Proxy Settigns on Windows OS and check that the values are persisted in Use the proxy server except for addresses that starts with.. textbox).

  5. Start the Cisco VPN client and connect to the VPN network.

  6. Start capturing traffic with Fiddler Everywhere.

  7. To ensure proper OS network configuration is preserved, refer to the Disconnection VPN section.

Due to some architectural differences in how VPN is set on macOS, you will need to strictly follow the order of

Reusing VPN

To prevent Cisco AnyConnect from using cached proxy information, we must first stop the Cisco VPN software and then close Fiddler Everywhere (or pause Capturing mode). The workflow for Cisco AnyConnect alongside Fiddler Everywhere is as follows:

  1. Start Fiddler Everywhere and enable Capturing mode.

  2. Connect the Cisco AnyConnect client.

  3. Capture traffic.

  4. Disconnect the Cisco AnyConnect client.

  5. Stop Fiddler Everywhere with disabled Capturing mode.

Preserving the order of execution of the above steps is mandatory for macOS users.

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