I am facing an issue with a Macbook pro on our home network that keeps changing IP addresses in an ascending order, and the other day the internet wasn’t working on it until I manually deleted the entry from the ARP table. I checked the logs in my Mikrotik router and found the following.
Right now the internet works on the macbook but the IP address won’t stop changing, and the Conflict by ICMP Response occurs multiple times a day.
Appreciate any help thank you!
Do you have any device in LAN which is configured to do proxy-arp? It can be any device: router, switch, AP … even an ordinary PC.
Hi mkx, we have the mix of devices such as Wireless Access Points (all hardwired by lan and setup as bridge mode / AP mode), Synology Disk Station, Apple TVs, Ecobee (Smart HVAC Thermostats), phones, tv, macbooks, and a PC, and none of them as far as I know are configured to do proxy-arp. Should I cross-check to ensure this is true?
So far, according to the Mikrotik log, the only device behaving this way is my father’s Macbook Pro.
Our home network is setup like this;
Fiber GPON ONT > Mikrotik Router (PPPoE) > Plug & Play Switch (to distribute the internet across the home) > devices
Appreciate your continued help, many thanks!
If that’s the only device misbehaving, then the problem lies within that device. It’s hard to tell if that device is misconfigured or it’s an interworking between that device and MT’s DHCP server or it’s device plain buggy …
You may try to make DHCP lease for that device static … it might help.
Thank you, I’ll give it a go and see how it goes.
Also, if I am not mistaken, as a general rule I should always set the static IP for a device in ARP menu and NOT the DHCP Server > Leases menu, right?
No, static lease is in DHCP server menu. ARP menu is best to be left alone, in principle any IP interface (e.g. bridge interface) learns MAC and IP mapping as it communicates with device. There are special cases when manual ARP table manipulation makes sense, but your case IMO isn’t one. And if there’s a mismatch, then router can not communicate with that device at all (and that means that interface looses connectivity outside its own subnet).
Thank you so much for your help and assistance, learned some useful information today 
@Mohamed, an off-topic question if I may: does life in Dubai differ from the usual one in any way due to COP28 meeting going on right now?
My pleasure!
There is not much difference in the usual daily routine, the COP28 is taking place where EXP2020 (2021) took place, a massive area dedicated to host such exhibitions, and it’s connected with the major highway, so if anything, perhaps some traffic jam increase. While security is surely upped it hasn’t caused any noticeable inconvenience. I can hear more helicopters though flying over my house much more recently lol, transporting VIPs, presidents, and important dignitaries.
COP28, oh you mean Continue Oil Production 28!