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1 answer
27 views

Hello,

In my application using FiddlerCore, I see that Windows Search Box on Windows 11 isn't able to make connections to the internet. I would like to be able to get this to work in some way but I'm not sure how.

 

I did some investigation by trying out Fiddler Everywhere and found that the same problems occurs most of the time, except sometimes when the root certificate is installed to machine store. I tried installing the certificate to machine store for my FiddlerCore application but it still didn't remedy the issue. 

 

Please let me know if there's any solution!

Nick Iliev
Telerik team
 answered on 19 Jan 2026
1 answer
204 views
Any plans to add HTTP/2.0 support in FiddlerCore?
Nick Iliev
Telerik team
 answered on 05 Jul 2024
2 answers
315 views
Hello, i have app using fiddler, and i have problem like in Subject. Proxy in windows settings turn on like normal but i can't see result of fiddler proxy. Im using windows 11. There's any way to fix that? Thanks! :) 
robert
Top achievements
Rank 1
Iron
 answered on 22 May 2024
1 answer
112 views
The last update for FiddlerCore was in 2021, is this product still being developed?
Rosen Vladimirov
Telerik team
 answered on 10 Apr 2024
0 answers
264 views
When I try to do that, it doesn't work
tgqz
Top achievements
Rank 1
 asked on 08 Apr 2024
1 answer
305 views

In my program; I use Fiddler Core. When ran on a pc; it set's the proxy as it should but when trying to browse the network with the proxy on; i'm getting "Your connection is Not private"; error message on all browsers. Please see attached photos for reference. Here is my running code:

 


private void stopfiddler()
{
    if (!FiddlerApplication.IsStarted())
    {
    }
    else
    {
        FiddlerApplication.Shutdown();
    }
}

public static void SavePreferences()
{

    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    string cert = ConfigurationManager.AppSettings["fiddler.certmaker.bc.cert"];
    string key = ConfigurationManager.AppSettings["fiddler.certmaker.bc.key"];
    if (cert == null || key == null)
    {
        config.AppSettings.Settings.Add("fiddler.certmaker.bc.cert", FiddlerApplication.Prefs.GetStringPref("fiddler.certmaker.bc.cert", null));
        config.AppSettings.Settings.Add("fiddler.certmaker.bc.key", FiddlerApplication.Prefs.GetStringPref("fiddler.certmaker.bc.key", null));
        config.Save(ConfigurationSaveMode.Modified);
        ConfigurationManager.RefreshSection("appSettings");
    }
    else
    {
        config.AppSettings.Settings["fiddler.certmaker.bc.cert"].Value = FiddlerApplication.Prefs.GetStringPref("fiddler.certmaker.bc.cert", null);
        config.AppSettings.Settings["fiddler.certmaker.bc.key"].Value = FiddlerApplication.Prefs.GetStringPref("fiddler.certmaker.bc.key", null);
        config.Save(ConfigurationSaveMode.Modified);
        ConfigurationManager.RefreshSection("appSettings");
    }
}

public static bool IsCertCreated()
{

    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    string cert = ConfigurationManager.AppSettings["fiddler.certmaker.bc.cert"];
    string key = ConfigurationManager.AppSettings["fiddler.certmaker.bc.key"];
    if (cert != null && key != null)
    {
        return true;
    }
    else
    {
        return false;
    }
}

public static void RemoveFiddlerPreferences()
{
    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

    config.AppSettings.Settings.Remove("fiddler.certmaker.bc.cert");
    config.AppSettings.Settings.Remove("fiddler.certmaker.bc.key");

    config.Save(ConfigurationSaveMode.Modified);
    ConfigurationManager.RefreshSection(config.AppSettings.SectionInformation.Name);
}

public static void LoadPreferences()
{
    string cert = ConfigurationManager.AppSettings["fiddler.certmaker.bc.cert"];
    string key = ConfigurationManager.AppSettings["fiddler.certmaker.bc.key"];

    if (!string.IsNullOrEmpty(cert) && !string.IsNullOrEmpty(key))
    {
        FiddlerApplication.Prefs.SetStringPref("fiddler.certmaker.bc.cert", cert);
        FiddlerApplication.Prefs.SetStringPref("fiddler.certmaker.bc.key", key);
    }

}
private void Installcert()
{

    if (IsCertCreated())
    {
        
    }
    else
    {
        BCCertMaker.BCCertMaker certProvider = new BCCertMaker.BCCertMaker();
        certProvider.CreateRootCertificate();
        X509Certificate2 rootCert = certProvider.GetRootCertificate();
        // Create a certificate store and add the root certificate to it
        X509Store store = new X509Store(StoreName.Root, StoreLocation.LocalMachine);
        store.Open(OpenFlags.ReadWrite);
        store.Add(rootCert);
        SavePreferences();
    }
}

private void Remove()
{
    using (var store = new X509Store(StoreName.Root, StoreLocation.LocalMachine))
    {
        store.Open(OpenFlags.ReadWrite);

        var certificatesToRemove = store.Certificates
            .Cast<X509Certificate2>()
            .Where(c => c.SubjectName.Name.ToLower().Contains("DO_NOT_TRUST_FiddlerRoot"))
            .ToList();

        foreach (var cert in certificatesToRemove)
        {
            string certPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, cert.Thumbprint + ".cer");
            if (File.Exists(certPath))
            {
                File.Delete(certPath);
            }

            store.Remove(cert);
        }
        RemoveFiddlerPreferences();
        store.Close();
        MessageBox.Show("Deleted");
    }
}

private void appentext(string value)
{
    if (InvokeRequired)
    {
        return;
    }
}

 

 

 

 

Nick Iliev
Telerik team
 answered on 26 Feb 2024
1 answer
391 views
How can I exempt all in FiddlerCore as if I was using the Win Config option in Fiddler Classic? Thank you in Advance!
Nick Iliev
Telerik team
 answered on 21 Feb 2024
1 answer
193 views

So; in one of my applications; I am attempting to try to find text within a decoded response. The problem is, that response changes every day. However, the format as you see below always stays the same BEFORE the numbers that are underlined. Only the numbers change. The end goal is to find this response; and then print it to a textbox. How can I accomplish this?

 

 

 

Nick Iliev
Telerik team
 answered on 06 Feb 2024
1 answer
109 views

I keep getting this error, no matter what I'm doing... I've tried both SaveRequestBody and SaveResponseBody. What am I doing wrong?

 

 

 

Nick Iliev
Telerik team
 answered on 05 Feb 2024
1 answer
190 views

Is it possible with Fiddler Core to completely replace a response like its possible with Fiddler Classic to do in the "RAW" section if you put a breakpoint before the Response?

Thanks

Nick Iliev
Telerik team
 answered on 22 Jan 2024
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