Software no entry state: core stop gracefully + no register

Hello guys,
I am new in the forum, so, thank you for the patience.
I have a situation where I would like to setup a “software no entry state” in my asterisk, without terminating active calls, without stopping it, and without registering peers/extensions anymore.

When I enter the asterisk “core stop gracefully” command, it stop making new calls and keep active the current ones, that is almost perfect, except that asterisk still accept registering peers/extensions.

Any ideas how could I do that?

Thanks in advance!