InformationClient certificates allow for the app to request a certificate for incoming requests. Only clients that have a valid certificate will be able to reach the app.
The TLS mutual authentication technique in enterprise environments ensures the authenticity of clients to the server. If incoming client certificates are enabled, then only an authenticated client who has valid certificates can access the app.
Utilizing and maintaining client certificates will require additional work to obtain and managed replacement and key rotation.
SolutionFrom Azure Console
Login to Azure Portal using https://portal.azure.com
Go to App Services
Click on each App
Under Setting section, Click on Configuration
Set the option Client certificate mode located under Incoming client certificates is set to Require
Using Azure Command Line Interface
To set Incoming client certificates value for an existing app, run the following command:
az webapp update --resource-group <RESOURCE_GROUP_NAME> --name <APP_NAME> --set clientCertEnabled=true
By default, incoming client certificates will be disabled when a new app is created using the command-line tool or Azure Portal console.