Spontaneous change of IP addresses and default gateway in a domain?

Question

Computer networks

Tell me how to fix the problem: Computers on which the IP addresses and the main gateway are changing began to "emerge" on the network! Let's say it was 192.168.0.25, but it became 192.168.2.25 and also with the main gateway It was 192.168.0.254, and when checking I notice 192.168.2.253!. I put everything down manually, it works... When you put "automatically" in the settings and check with ipconfig again, the same picture turns out with a change of addresses .. The server is 2008, everything is fine on it. Tell me, what's the problem?

Answer 1

You have a dhcp server on your network and if you don’t know about it, then this is a problem

Answer 2

Look for an "unregistered" (well, or "registered", but then you'll have your hands off) wifi router with dhcp enabled.
And so - turn on DHCP snooping to get rid of them if you cannot physically find them.