proxy issue started after installing Fiddler, how do i resolve it?

1 Answer 1945 Views
Fiddler Classic Fiddler Everywhere
Gabriel
Top achievements
Rank 1
Gabriel asked on 25 Feb 2022, 01:03 AM

When I run an app as the Windows LOCAL SYSTEM account, using psexec, and try to access a WebService, it appears to be failing Authentication with the following error message:

No connection could be made because the target machine actively refused it 127.0.0.1:8888

I checked the logs, and this dates back to when I installed Fiddler and was using it to test this app by impersonating requests as the LOCAL SYSTEM account. I've tried looking through the settings and even uninstalled Fiddler, restarted the machine, but I continue to get this error on my machine?

It's not happening on other machines or when I run the app at my own account on my machine. I'm really stumped here, I read this link, but uninstalling it didn't work and I have no proxy set on the machine, it's set to Automatically detect settings:

https://www.telerik.com/forums/disable-fiddler-as-system-proxy

1 Answer, 1 is accepted

Sort by
1
Accepted
Nick Iliev
Telerik team
answered on 28 Feb 2022, 07:29 AM

Hello Gabriel,

 

Apart from verifying that you have no manual proxy being set in your main OS proxy settings, you can also check if there is a proxy set in the LAN settings.

- Open a terminal and type inetcpl.cpl

- Go to Connections and open LAN settings

- Remove the FIddler proxy if such is being set in the Proxy Server field.

 

 

Regards,
Nick Iliev
Progress Telerik

Virtual Classroom, the free self-paced technical training that gets you up to speed with Telerik and Kendo UI products quickly just got a fresh new look + new and improved content including a brand new Blazor course! Check it out at https://learn.telerik.com/.

Gabriel
Top achievements
Rank 1
commented on 28 Feb 2022, 07:45 AM

Hi Nick,

Thanks for the reply. I actually was able to resolve the issue today.

I was not seeing any proxy under my personal account, but when I ran a browser under the SYSTEM account (via psexec) I was able to see the Proxy Server settings for the loopback address (127.0.0.1:8888).

I think this is because I was running Fiddler as the SYSTEM account, so that I could impersonate SYSTEM and run some Postman tests, but then Fiddler created the Proxy Settings under that account only. When I was opening Fiddler as my personal account, these settings were not there, they didn't get removed when I closed the application it seems and even when I uninstalled Fiddler, it did not remove that Proxy Server setting?

Possibly something that could be investigated? But for me at least, I shouldn't have the same problem again.

Tags
Fiddler Classic Fiddler Everywhere
Asked by
Gabriel
Top achievements
Rank 1
Answers by
Nick Iliev
Telerik team
Share this question
or