If a microservice-oriented application requires high security and you want to restrict access to it from other applications, you can authenticate the applications that call the microservice-oriented application. This ensures that only the applications that match the authentication rules can call the microservice-oriented application.
Background information
This topic uses an example to introduce scenarios where Dubbo service authentication is performed.
Consumers 1, 2, and 3 and a service provider are deployed in the same namespace. By default, Consumers 1, 2, and 3 can call all the services and interfaces of the provider.

You can specify an authentication method for all the services and interfaces of the provider. For example, set the authentication method to Blacklist (call denied) for Consumer 1 and set the authentication method to Whitelist (allow calls) for Consumer 2 and Consumer 3.
Then, you can also set an authentication method for specified services and interfaces of the provider. For example, after you apply the preceding settings, Consumer 2 and Consumer 3 can access all services and interfaces of the provider. However, Service and Interface 2 of the provider involves core business and data. To disable Consumer 2 from accessing Service and Interface 2, set the authentication method of Service and Interface 2 to Blacklist (call denied) for Consumer 2. This way, Consumer 2 can access only Service and Interface 1 and Service and Interface 3 of the provider.
The following figure shows the application call process after you configure the authentication rules.

Create a service authentication rule
Verify the results
After the service authentication rule is created and enabled, check whether the rule takes effect.