new interface was built on FTD for Meraki device management.

[Rock29]

The one Access Point Migrated is complaining: - "Uplink IP address in conflict with another device - " - indicating a duplicate IP Address

AP MAC Address = e455.a82d.4048 
IP address = 172.10.10.5 (handed out via the FTD DHCP pool).

When we look at the ARP table on the AP we see the following conflict - hence the Meraki Portal error: -
IP            MAC
172.10.10.5         48:2e:72: fb:40:29 - Firewall also claiming to be .30.
172.10.10.30      48:2e:72: fb:40:29 - Firewall MAC address (the gateway for the Access Point)

MAC address 48:2e:72: fb: 40:29 is on the Firewall.
Interface Ethernet1/6 "infra-mgmt", is up, line protocol is up.
  Hardware is EtherSVI, BW 1000 Mbps, DLY 10 usec
        MAC address 482e.72fb.4029, MTU 1500

[Sheraz.Salim]

Did you exclude (excluding the gw ip) the ip address on FTD-DHCP server? if you excluded and start from .50 to 70. and test it.

[Rock29]

Hi, thanks for your help so far. Can you please share the steps or commands to exclude/reserve the IP address in FTD-DHCP-Server. 

[Rock29]

It's excluded in DHCP. Can you please share the steps that we can verify from FTD and Meraki side. 

[Sheraz.Salim]

can you go into the CLI of FTD and give this command

clear dhcpd binding 172.10.10.5
clear dhcpd binding 172.10.10.30

[MHM Cisco World]

are you config mgmt interface connect to INside of FTD with DHCP ?
if So then the mgmt interface get IP from FTD and this IP is same as AP get. 

[Rock29]

Hey, Thanks again for your reply. Actually, we don't have access to the customer devices. This is something customer raised to us for the technical help.  

So, I just want myself to be prepared before going into the troubleshooting call and device access. 

Actually, A new interface built for the Meraki Device management and that interface MAC address is conflicting with Meraki Device.  

Can you please help me the steps for the troubleshooting steps by steps. Not sure about the option of IP address exclusion in FTD DHCP server. 

[Rob Ingram · Accepted solution]

@Rock29 proxy arp? check NAT rules.