Received conflicting ARP on interface ethernet

[cdcirexx]

Hi all, after exporting the old config from my old pa500 to the 820, I had an old interface that was for my  wifi vlan, that used to be a physical int on the 500 but I needed to remove it since now the 820 only has 4 ethernet ports, I reset it as a sub-int on the 820, but now I'm getting this message "Received conflicting ARP on interface ethernet1/1.60 indicating duplicate IP 172.16.xx.xx, sender mac 58:49:3b:a0:a6:14"

I could not find where this mac address is, we still have our old unifi system that was in the wifi vlan, but I shutdown the ssg pro4, and only have an old acpro that's not in that vlan anymore, I cleared all the switches arp's and somehow this mysterious mac address keeps popping up on one of the switches and is showing up on the pa820 logs. Anyone seem this before or have any ideas, thanks in advanced.

[OtakarKlier]

Hello,

I could be off base, but have you cleared the arp cache from the switch?

Regards,

[cdcirexx]

Thanks for the response, yes I cleared arp on my 2 catalyst switches, and on the pa820 as well through cli, also it keeps showing an incomplete address for my wifi vlan address of 172.16.60.xx on the 820, I have an open ticket with support but they can't seem to figure it out too. Should I try and remove the sub interface to see if the messages goes away

[OtakarKlier · Accepted solution]

That mac address is a PAN address. If you do a the following command via cli, it should show you which interface the mac belongs to:

show mac all

Also since it was a wifi vlan, what devie is doing the DHCP for the clients? Does the PAN need to be setup as a relay?

Regards,

[cdcirexx]

Hi otakar,

Yes I did show mac all on the 820 it showed nothing, but when I do sh arp eth1/1.60 it shows the ip of my cisco svi int that's connected to the 820 sub-int. But the message about the arp ip conflict still shows on the system log, this started when I removed the physical int for that ip and made it into a sub-int.

[cdcirexx]

About the dhcp, I'm using the built in dhcp on my aruba iap

[cdcirexx]

Another thing, that mac address also shows up on one of my cisco sg300 switch that's on another bulding, I had our old unifi ap hooked up to that switch before, I took it down already and tried to clear the arp table on the switch as well.

[cdcirexx]

Figured it out, our old pa500 was still hooked up on the core switch, your right it was a pan mac address, it was int1/5 of the pa500, I unplugged it and the messages went away. Can't believe I missed that