I’m a bit confused. When I open Kid Control - Devices I see a dynamically changing list of ~100 unknown mac addresses. If I delete some, they return.
What’s the issue behind?
Docs says it comes from the ARP table; and the default mode is Enabled. So does it mean those are devices connected to the same ISP?
Most smartphones these days have feature of using randomized MAC addresses (and they have it enabled by default).
The other thing for you to check is which router’s interface do they map to?
Thx for fast response!
No phones, I see hundreds. The Mac address of 90% of them belongs to Huwaii. My ISP gives every customer a Huawaii cable modem. (My one is bridged to the MikroTik) .
How can I do?
So how? Any hint is appreciated 
pics: https://photos.app.goo.gl/5TC6cYcJ6r21ZUsw6
left shows the kids control device list, right the ARP list (only devices got an IP)
If you go to IPv6 → Neighbors, you’ll probably see most of those “unaccounted for” MAC addresses being listed there. And the corresponding interface is probably your WAN interface. It looks like your ISP put multiple customers on the same broadcast domain and provides no isolations between them. Which means they are “discoverable” to your router through neighbor discovery https://en.wikipedia.org/wiki/Neighbor_Discovery_Protocol on the WAN interface, maybe from unsolicited Neighbor Advertisement messages.
If you have no uses for IPv6 then you can turn it off under IPv6 → Settings. If you need IPv6, then you have to make sure your IPv6 firewall is properly configured. Use the firewall configuration from defconf if you have RB devices, or from https://help.mikrotik.com/docs/display/ROS/Building+Advanced+Firewall for CCR/CRS devices (your internet interface should be in the WAN interface list).
Thx for your worthful hints! I gonna disable IPv6.