microtik. How to block access to the local network?

Question

Mikrotik

Good day. The main Mikrotik hAP lite router is RB941-2nD which distributes DHCP. There are devices on the network (I don’t know who connected it) that also distributes DHCP, due to which there is a conflict of IP addresses. I found this device blocked internet connections. I also need to restrict by MAC or by IP connections to the local network. Couldn't resolve this issue. How to do it?

Answer 1

Vsmysle YOUR router and YOU do not know who connected something there?
So block it by MAC. It from you the Internet received on DHCP?

Answer 2

This router is at work. An unconfigured (with DHCP enabled) wi-fi router is connected to a common network (there is equipment that needs to be connected to the Internet, a person working on the night shift simply pulls out the cable connected to the equipment and connects it to his wi-fi router and so uses the Internet. Caught this smart guy, but this is not him, since the previous one quit.) The wi-fi router connected to this network must be limited from the local area.