How do I find which computer is using a particular private IP address? For instance, when I ping 192.168.18.30, I get a message "Reply from 192.168.18.30: bytes=32 time =1 ms TTL=32". I don't know which computer has this IP address. I looked at 'Address Leases' and 'Reservations' in DHCP of our Windows Server 2003 machine, but it does not include this IP address. Is there some other way of determining which computer is using this IP address? Thanks, in advance, for your help! - Charles
I can help you narrow it down, but unless you are using a managed switch it's the best you're going to do. By the sound of it you're using Windows so I'll give you instructions for that
1) Open a command prompt on a machine on the same subnet (this is important, this won't work from a different subnet)
2) Ping the address and make sure you get a response
3) Type "arp -a" and find the reported "Physical Address" for that IP
4) Lookup the first 6 hex digits here
You can use that manufacturer to take an educated guess what the device is.