I have a device that failed to its DHCP query. If I change its MAC address it works.
I suspect a MAC address is already registered somewhere on the network. I know that during a DHCP request the DHCP server test if somebody answer to the registered MAC before the re-affectation.
How can we simply check if a MAC address is already registered on the network?
Of course I don't have access to the DHCP server neither the network switches.
arp -a which gives me a big list of IP, but I doubt it's all the IP addresses of my network.