Hello dear,
I’m facing a big problem on my network. I receive many messages of IP conflict on my desktop. I check the Event log and I found the MAC 1A:A6:F7:C9:78:C1.
I tried to block this MAC but I still see this MAC in ARP and DHCP.
Someone has any idea?
Maybe that device is slightly misconfigured, with enabled proxy ARP or something. Good first step would be finding out what that device is.
Could you have two DHCP servers that are serving addresses in the same IP range? That’s the most common reason for having multiple devices with the same IP address. If it was just one, IP, I would expect a device mis-configured, but it looks like you have several duplicates.
Oh, I didn’t catch that it was the same MAC showing up on almost every IP issued. Not likely a DHCP issue. that’s what I get for not reading completely…
It seems that here is a device some kind of proxy ARP or auto IP aliasing.
Is it possible that you have a router with both wan and lan port connected to your network, which has IP aliasing enabled?
(e.g. UBNT APs have this functionality…)
And since 10.10.10.1 is the only one not duplicated, I would start with that one…