HOWTO: Use Fiddler with a SOCKS proxy

[EricLaw]

Q: I have a SOCKS proxy and I want to use it upstream of Fiddler, but Fiddler does not chain to it automatically.

Q: I want to use the TOR network upstream of Fiddler. How can I tell Fiddler to use the local TOR SOCKS endpoint?

 

This topic is covered in detail in the Fiddler Book:

Using the X-OverrideGateway flag, use the socks= prefix to indicate that Fiddler should use the SOCKS v4a protocol when speaking to the upstream server.

 

For instance, the TOR installer sets up an entry point to the TOR network using a SOCKS proxy on port 9150 called Polipo. You can add the following inside your FiddlerScript’s OnBeforeRequest method to route any request to test.example.com through the TOR network: 

    if (oSession.HostnameIs("test.example.com")) {

      oSession["x-OverrideGateway"] = "socks=127.0.0.1:9150";    

  }

If you’d instead prefer to send all of the traffic via the SOCKS, you can simply set the X-OverrideGateway flag unconditionally for each Session.

[Vahid N.]

Hello,

Is it possible to start the Fiddler or FiddlerCore as a SOCKS proxy and listen to socks request from the browser or an application? (I don't want to forward the HTTP requests as SOCKS requests)

[EricLaw]

No, at present, Fiddler is not able to act as a SOCKS server.