Hi, I have strange IP adresses showing on my router, from IP’s that do not exist, anybody any idea what it could be ?

192.168.88.x range is from the default config of the mikrotik. I bet you didn’t change it, and the dhcp is giving those addresses out to someone.
No, that’s not the case, If you check the right side of the image I posted you will see the ARP table of connectred IP’s, also you can see adresses windows there you will see IP networks that are active. so the IP’s in the table are really not existing IP’s .
Do you have DHCP running? If so, look at the IP Pools.
I have DHCP’s 1 for every lan port, and is 192.168.2,3,4,5.0/24 that one you can also see on the image, and also you can see that the old dhcp with 192.168.88.1 for wlan is red/turned off.
so I dont have anything with such IP, but most important on the image you can see the ARP, all active IP’s you can see there, there is no such IP. that’s why I dont understand where is this from.