Deny access to dynamic namespaces, not specified it config file?

[psvmcc]

Hi, I would like to ask, if it possible to proxy only to namespaces specified in config file, and drop any other requests?

Example, in config file I have only docker.io namespace, and for query any other namespace should be dropped/denied/not proxied.

Maybe Its possible to add this flag to command-line options?

Thanks!