authenticator
When TLS is enabled, a null authenticator (the default) will allow clients whose certificate chains can be verified by one of the OS-bundled root certificates. There are two types of TLS authenticators. See ListenerCertificateAuthenticator
When TLS is disabled, a null authenticator (the default) will allow all clients. A non-null authenticator will be passed the client's credentials and is completely responsible for authenticating them. See ListenerPasswordAuthenticator