on a windows machine:
1. ping ip_address
2. arp -a ip_address
Step 2 gives you the MAC address (physical address) of the device that is using the ip-address.
A MAC address is programmed into the ethernet device by the manufacturer/vendor of that device.
Using google search terms:
mac address lookup
you can find webservices that can find the vendor for a given MAC-adress
3. enter the MAC address from step 2 into one of the webservices
Now you have the vendor of the ehternet device that using the ip-address. Sometimes this is enough to identify it, sometimes not.
Other things to try to identify the device:
1. ping -a ip_address
2. visit
http://ip_address using a web-browser
3. visit
https://ip_address using a web-browser
4. telnet ip_address
5. putty ip_address
