Hi Fiddler Team,

I'm conducting an analysis on origin referer and have 4 scenarios:

1. No Origin, No Referer

2. No Origin, Referer Present

3. Origin Present, Referer Missing

4. Origin Present, Referer Present

Can you please help me to understand why origin and / or referer are missing (scenarios 1-3)?

Thanks!

In my network environment, I cannot access unpkg.com, which causes some of my web pages to load improperly. I can access unpkg.zhimg.com, which can replace unpkg.com. Therefore, I'm wondering if I can use Fiddler to replace all accesses to unpkg.com with accesses to unpkg.zhimg.com. To do this, I used the following code in FiddlerScript:

if (oSession.HTTPMethodIs("CONNECT") && (oSession.PathAndQuery == "unpkg.com:443")) { 
          oSession.PathAndQuery = "unpkg.zhimg.com:443"; 
}

if (oSession.HostnameIs("unpkg.com")) oSession.hostname = "unpkg.zhimg.com";

When I try to access unpkg.com, I encounter the following error:

"fiddler.network.https> HTTPS handshake to unpkg.com (for #2) failed. System.Security.Authentication.AuthenticationException."

From the error message, it seems like Fiddler is still attempting to establish a connection with unpkg.com before accessing unpkg.zhimg.com. Is it possible to configure Fiddler to directly access unpkg.zhimg.com without attempting to connect to unpkg.com first?

My client said that they are having issues with Outlook 365 via the local Outlook app when Fiddler is also open/running.

The client goes to open outlook and it just sits and spins and never opens. But as soon as she closed out of Fiddler, she was able to open email no problem. They have even had to reboot their computer in order to open Outlook. 

See attached for how I have their settings set up.

I need to use client certificate for some requests. In old Fiddler I did this using FiddlerScript using 

    static function OnBeforeRequest(oSession: Session) {

	if (oSession.host.toLowerCase() == "aaa.bbb.com")
	{
		oSession["https-Client-Certificate"] = "C:\certs\aaa.bbb.cer";
	}
    }

Hi 

Fiddler cannot intercept a request from spotify.com

TLS handshake failed

Hi,

I am trying to pick up HTTP requests from a program but when this program sends http requests, through TCP View I can see that it sends it on my machine's 192.x ip instead of 127.0.0.1 and fiddler is not picking this up. Any clues on how to fix this?

Thanks!

Hello, I'm trying to output the HTTPVersion in FiddlerApplication.AfterSessionComplete,

but sites corresponding to HTTP/2 always show up as HTTP/1.1.

source code:

When I open Fiddler Classic, the Firewall rules no longer work. For example, I have a rule blocking all outbound traffic from Google Chrome. When Fiddler is not opened, the rule works and I am unable to access the internet through Chrome, but once I open Fiddler, the Firewall rule stops working and I can browse the internet normally.

I believe this has something to do with Fiddler connecting me to a proxy which bypasses the Firewall. So I tried unchecking “Act as system proxy on startup” under Options → Connections, but this causes Fiddler not to record any traffic at all. I also tried selecting “No Proxy” under the Gateway tab, but this does not seem to have any effect.

How can I fix this issue? Do I have to configure the Firewall settings to apply to the proxy? I am using Windows 10.