Hello,

951G-2HnD, typical setting (DHCP, NAT)
In the logs I periodically see

Detected conflict by ARP response for Y.Y.Y.Y from xx: xx: xx: xx: xx: xx

where Y.Y.Y.Y is a host somewhere in the provider's network

Do I understand correctly that there is a configuration error somewhere, since the router receives an ARP response from the provider's network?

Go to IP>ARP if the same IP is on a different MAC then that is the issue. Either change or delete from ARP table.

It means you have a statically assigned ARP assigned and another client trying to update the same arp.

Deleting statically assigned IPS from ARP table may not allow pinging.

Go to IP>ARP if the same IP is on a different MAC then that is the issue. Either change or delete from ARP table.

It means you have a statically assigned ARP assigned and another client trying to update the same arp.

Deleting statically assigned IPS from ARP table may not allow pinging.

Thanks for the answer,
I checked, mac address xx:xx:xx:xx:xx:xx is not present in the arp list of the router, also, there are no duplicates

Hello riwer,

are there no duplicates of the MAC or have you also checked the ip address.
I would recommend to start some pings to the mentioned IP address right before the check.
It is possible that you have IP address is double assigned.

If you have a pubic ip range from your ISP, check that you all addresses are are free.
Sometimes the ISP use one address of this range as gateway for your connections.

Hello riwer,

are there no duplicates of the MAC or have you also checked the ip address.
I would recommend to start some pings to the mentioned IP address right before the check.
It is possible that you have IP address is double assigned.

If you have a pubic ip range from your ISP, check that you all addresses are are free.
Sometimes the ISP use one address of this range as gateway for your connections.

I will try to describe in more detail

I am using the range 192.168.1.0/24 on my local network and Y.Y.Y.Y = 192.168.173.1

The tracert command from a windows host on the local network reaches 192.168.173.1 in the seventh step (I repeat once again, this is a host somewhere in the local network of the provider)

There is neither 192.168.173.1 nor xx: xx: xx: xx: xx: xx in the arp list of my router (even when I ping 192.168.173.1 from the router)

And I don't quite understand if it is the norm for a message like

Detected conflict by ARP response for 192.168.173.1 from xx: xx: xx: xx: xx: xx

in the logs of my router or this indicates an error in the router configuration in terms of security

Hello,

I found this article viewtopic.php?t=155523 which describes the same error massage.
I am not sure if this could be helpful, because it describes, that the error is raised by the Mirkrotik-DHCP-Server, but the point

There's a device configured with proxy-arp and acts for addresses which it should not

by mkx
could possible a cause of the error, even if it is on a other device.
In the original post, a IPv6 address response to a IPv4 query, so perhaps...