Well depends if you're running a static or DHCP Network. Because technically you're router would tell you what addresses are being used and which ones are not.Want to know what IP address's are on your network??
here is a little command you can run from the command promt.
it will ping all IP's in your subnet to see if there is a reply and save it to a txt file in root.
FOR /L %i IN (1,1,254) DO ping -a -n 1 192.168.0.%i | FIND /i "Reply">>c:\ipaddresses.txt
have fun, can be very useful!
I use DHCP reservations in my network so I know what IP address all the devices are assigned and I leverage that functionality inside my router. This way all the products can still have DHCP support without me having to statically assign them. But it also keeps a table for me in case I forget what their IP address is. And if I need to move the product to another network, at least it's not a sign of static IP address that might create this certain level of difficulty