Generate Developer Certificate for ASP.Net Core on Linux

Problem

To develop ASP.Net Core Web Apps on Linux you need to generate self-signed developer certificates. This works fine under Windows and Mac OSX with 'dotnet dev-certs https --trust', but not under Linux operating systems. You will get SSL Connection errors if two Wep Apps need to communicate with each other or you want to access it via browser.

Solution

You need to generate self-signed certificates with OpenSSL to successfully use them. To be fully compatible with Firefox and Chrome, you need to setup a local trust chain. To simplify the process of generating these certificates for developers this script was created.

Tested with:

• Ubuntu 20.04 and .NET 5.0
• Arch Linux (5.12.14-arch1-1) and .NET 5.0

What will it do?

1. Create a self-signed Root CA certificate.
2. Add the Developer Root CA certificate to the trust store.
3. Add the certificate to the browser's trust store (certutil).
4. Create a self-signed server certificate to use in dotnet development.
5. Add the generated certificate to aspnet environment 'dotnet dev-certs https --trust' to use it without any custom configuration of Kestrel in e.g. appsettings.json

How To

Clone or download this git repository and make the script corresponding to your system executable.

chmod +x ./setup_dev_certs_ubuntu.sh

Execute the script

./setup_dev_certs_ubuntu.sh

You will also be asked to enter your sudo password, as adding the certificate to the trust store requires elevated privileges.

Dependencies

• libnss3-tools (script will ask you to install if not found on your system)
• dotnet SDK (you should already have this)

References

Stack Overflow: How to run 'dotnet dev-certs https --trust'

Github Issue: dev-certificates on Linux -- how to get dotnet-to-dotnet comms to work? #7246

Github: BorisWilhelms/create-dotnet-devcert