You can install nmap on your machine and get it to inquire about your network. Info about it can be found
here[
^].
This tool will tell you what nodes are on your network, their MAC address and the MAC vendor. If my network is 192.168.1.*, the command I would use on my linux box is
sudo nmap -sP 192.168.1.0/24
which scans my network and reports on all nodes on it. [For the windows version, remove the 'sudo'.]