Skip to main content

Fiddler error–HTTPS handshake failed

This is a follow-up on a post from 2013(!). There I talked about how we used Fiddler to inject a client certificate to authenticate the request.

This application is still in use today, and we still use the same trick to authenticate when debugging locally. Last week, a colleague contacted me that this approach didn't work anymore. When he tried to connect to the service it failed with the following error message:

fiddler.network.https> HTTPS handshake to <site> (for #1) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception.

We discovered that the root cause of the issue was that the server was expecting a TLS 1.2 connection and we were using a TLS 1.0 connection.

We had to take 2 steps to solve the issue:

Step 1 – Update Fiddler

We first had to update Fiddler. Therefore go to https://www.telerik.com/download/fiddler and download the latest version.

Notice that we downloaded Fiddler Classic not the cross-platform Fiddler Everywhere version.

Step 2 – Update the list of supported HTTPS protocols

Open Fiddler and click on Tools  --> Options… .

Go to the HTTPS tab and click on the link next to the protocols label:

Add TLS1.2 to the list of protocols:

Click on OK twice to close both popups.

Labels:

Popular posts from this blog

.NET 8–Keyed/Named Services

A feature that a lot of IoC container libraries support but that was missing in the default DI container provided by Microsoft is the support for Keyed or Named Services. This feature allows you to register the same type multiple times using different names, allowing you to resolve a specific instance based on the circumstances. Although there is some controversy if supporting this feature is a good idea or not, it certainly can be handy. To support this feature a new interface IKeyedServiceProvider got introduced in .NET 8 providing 2 new methods on our ServiceProvider instance: object? GetKeyedService(Type serviceType, object? serviceKey); object GetRequiredKeyedService(Type serviceType, object? serviceKey); To use it, we need to register our service using one of the new extension methods: Resolving the service can be done either through the FromKeyedServices attribute: or by injecting the IKeyedServiceProvider interface and calling the GetRequiredKeyedServic...
Read more

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...
Read more