Throttling network speed using Fiddler is not working

Question

The problem I am facing is almost similar to the following thread:

Unable to control the network bandwidth using fiddler in spite of custom rules?

I want to throttle my network speed by following the steps as mentioned in Simulate network speeds using Fiddler

But even after doing the above settings the network speed still remains the same.

I am mentioning the steps I followed to downgrade my internet speed:

1. Launched Fiddler
2. Navigated to Rules-> Customize Rules..

3. Found the below code and changed the value accordingly in CustomRules.js.

   if (m_SimulateModem) { // Delay sends by 300ms per KB uploaded. oSession["request-trickle-delay"] = "500"; // Delay receives by 150ms per KB downloaded. oSession["response-trickle-delay"] = "500"; }

4. Saved the file by Ctrl+S

5. Closed the file.
6. Checked the flag "Simulate Modem Speeds" Now ideally the speed should be very less somewhere around 2kb/s (If my calculations are not wrong)

But the download and Upload speeds are close to 10 MBPS when measured using Speedtest.net. I tried closing the browser, fiddler etc but nothing helped.

Can you please tell me If I am missing something?

Also one more thing after saving the file in Step 4 above, when I navigated to the file CustomRule.js in the installation folder (C:\Program Files (x86)\Fiddler2\Scripts) it still showed the old values as mentioned below:

if (m_SimulateModem) {
// Delay sends by 300ms per KB uploaded.
oSession["request-trickle-delay"] = "300"; 
// Delay receives by 150ms per KB downloaded.
oSession["response-trickle-delay"] = "150"; 
}

Please guide me if I am doing this in a wrong way, let me know if I need t provide any more info.

Thanks!!

Namit

Answer 1

You can use other resources like speedof.me to measure speed of connection through Fiddler.

Answer 2

SpeedTest.net uses Flash and writes directly to a socket, bypassing the proxy. You cannot use Fiddler to slow its traffic.