How to disable access to the Internet for a port \ device on mikrotik?

Question

Computer networks

There is Mikritik hexs
Tell me how can I disable access to the Internet, but allow any local connections, to a specific device \ port (eth3 for example)

The Internet rises on Mikritik via PPoE connection

Answer 1

Well, as far as I know, this can only be limited to a subnet or a list of ip addresses in the firewall. a specific port can only be on or off

Answer 2

Elementary Watson!
If a packet entered through the eth3 interface and wants to leave through eth1 (usually home routers turn to eth1), then fuse it!
If a packet comes from a device with an IP ... and wants to leave via eth1 - fire it!