This page allows you to generate an x509 certificate suitable that will allow you to connect to the TLS enabled ports on test.mosquitto.org that require a client certificate, i.e. port 8884.
To use it, you will need to generate a PEM encoded Certificate Signing Request (CSR) and paste it into the form. After you submit the form, the certificate will be generated for you to download.
Generate a private key:
Generate the CSR:
When you are generating the CSR, please do not use the default values. At a minimum, the CSR must include the Country, Organisation and Common Name fields.
You should paste the contents of client.csr into the form.