The answers are /var/lib/dhcpd/dhcpd.leases & /var/lib/dhcpd/dhcpd6.leases
In order to look up ipv4 and ipv6 dhcp leases, The two files that should be viewed are /var/lib/dhcpd/dhcpd.leases & /var/lib/dhcpd/dhcpd6.leases
Answer:
Try checking around on the router!
Explanation:
Assuming they haven't changed it, most routers have their default password displayed somewhere on it. I hope this helps!! ^^