If you want to find out a IP of a unknown device (you dont know its last 2 sections, you have no manual, default was changed, person that changed it is no dead by that I mean no obvious answers), how do you do it?
Do you set a PC to 192.168.1.1 SUB: 255.255.0.0 GW: 192.168.1.1, connect it directly to the device, nmap a ping scan thru all ips and it should show up?
Thats the way I do it but with something on my network.
Best Answer +BudMan , 13 March 2014 - 15:56
while I agree that all networks are different and one tool might not be the best for a specific network. If its a device you have your hands on you can always connect your laptop to the interface to sniff what its sending. But sure if don't know where the device is in the DC and its only unmanaged switches you can have issues tracking something down for sure.
More than happy to discuss all the different ways that you could find an IP from a device in lots of different scenarios - since depending on the situation, different methodologies and or tools maybe be leveraged for the best way to get the information your seeking.
If you know its dhcp, I would just look to dhcp leases - especially if you know the mac from the outside of the device for example or its unique hardware so you would notice it from the first 3 of the mac per a vendor lookup, or that its different from all your other dhcp clients.. Or you can boot it and see the timestamp on the lease and rule out your known devices, etc..
If its something you bought off ebay or got 2nd hand can and not reset or console in, then I would connect it on an isolated network (say a laptop only with sniffer) and find its IP and then try to access interface from that IP, etc. Or run a dhcp server on your laptop to give it an IP. I would be hesitant to just connect some 2nd hand device to a production type network without first looking at its config or reset, etc.
Scanners can come in very handy in mapping out a network when you don't have access to managed switches or devices are quite - some will send out more noise then others and if busy network sometime there can be a lot of noise to go through if your just looking for devices on network. Some devices might not even respond to a ping sweep though and looking at traffic might be required to catch when they arp for say their gateway IP, etc.
There is many variables that could come into play, every situation could be be vastly different.Go to the full post