On Thu, 22 Mar 2018, David wrote: > Does Debian keep a table of MAC addresses? If so where can I locate it?
The kernel does. You can get the ARP table e.g. with ip neigh list This table is relatively short-lived and if you haven't talked to that device recently it might not show up in the table. Another place you could look for MAC addresses is your router. Most routers keep a table of MAC addresses which is a bit longer-lived than the ARP table on a host, because they need to hand out IP addresses over DHCP and need to remember the MAC-IP combination for some time. Thomas