$ brew install nmap # or sudo apt-get install nmap
$ sudo nmap -sP 192.168.1.1/24
Starting Nmap 7.60 ( https://nmap.org ) at 2018-03-23 12:00 EDT
Nmap scan report for FIOS_Quantum_Gateway.fios-router.home (192.168.1.1)
Host is up (0.046s latency).
MAC Address: 48:FF:FF:FF:FF:FF (Verizon)
Nmap scan report for Living-Room.fios-router.home (192.168.1.100)
Host is up (0.012s latency).
MAC Address: 78:FF:FF:FF:FF:FF (Arris Group)
...
$ brew cask install fing
$ sudo fing
11:53:32 > Discovery profile: Default discovery profile
11:53:32 > Discovery class: data-link (data-link layer)
11:53:32 > Discovery on: 192.168.1.0/24
11:53:32 > Discovery round starting.
11:53:32 > Host is up: 192.168.1.151
HW Address: 6C:FF:FF:FF:FF:FF
Hostname: richards-mbp.fios-router.home
11:53:32 > Host is up: 192.168.1.1
HW Address: 48:FF:FF:FF:FF:FF
Hostname: fios_quantum_gateway.fios-router.home
11:53:32 > Host is up: 192.168.1.100
HW Address: 78:FF:FF:FF:FF:ff
Hostname: living-room.fios-router.home
...