At a cmd prompt you can use
That will give you IP's and MAC's but no names. Note that it will also list any machines you are connected to on the internet at that time, so don't freak out is you see an IP listed that you don't recognize. You can then run
and it will give you the machine name of that IP. You will have to run tracert for each IP so it will be a little work. May or may not be easier than going to each machine and simply looking at the IP address.
Another way is to use Wireshark, while you have it capturing network activity go into your network and connect to a machine and you will be able to see the IP that it is connecting to.
There are tools out there that do what you want and more, but they are more along the lines of hacker tools so they don't get mentioned out in the open too often.
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