How to solve the problem with the Mikrotik router when wi-fi clients connect to someone else's DHCP server?

Question

System administration

Good morning!
There was such a problem:
a Mikrotik router, a wi-fi access point is configured, clients successfully connect to it, but somehow miraculously get into someone else's local network.
Ipconfig says that the client has connected to someone else's dhcp server, which is located on a completely different network. Mikrotik belongs to the 192.168.0.0/24 network, while dhcp clients go to the 192.168.1.0/24 network.
tell me how to solve this problem

Answer 1

Turn off the router's DHCP server.

Answer 2

If it is possible to configure DHCP snooping on the point, specifying only the uplink port where your Mikrotik is as a trusted port for DHCP requests, I also advise you to prohibit traffic between Wi-Fi clients not through the gateway, the option is called wireless isolation or something like that.

Answer 3

Create a rule that prohibits forwarding UDP packets with destination port 68. This is if the left DHCP server is located behind the Mikrotik network.
If this server is inside the local network, then find the culprit by MAC and punish :)