Find out a device by knowing IP

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I have a peculiar situation where I have 3 valid IPs which are pinging
in my network but to my knowledge we have not allocated these IP to any
box or devices. When I to a tracert, I find that it is within my
network and not outside. These are the IPs from the pool of reserved
IPs for us.

We have tried isolating cables from the external switch to identify
which device is having the IP but were not able to find. These IP are
pingable and no HTTP or FTP or any other port is open.

How can I locate these devices of machines within my network. Is there
any tool? or any manual method to get the info??

Thanks in advance


Re: Find out a device by knowing IP wrote:
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No there is no such tool. It mostly depends on what kind of switches,
routers, etc. you have and how much they can tell you. I primitive dumb
cheap switch won't tell you anything about what's connected and where. A
   managed switch on the other hand reveals a lot about what's connected.

I would start with your traceroute output to identify the last router on
the way there. They must be somewhere connected there, either directly
to the router or somewhere from there, maybe with a switch/hub or similar.

Next check "arp" to find out the MAC address. You can find out the
manufacturer of the ethernet card in the internet when you know the MAC
address which may help occasionally. Check whether the same MAC address
is used for another IP address as well. Maybe someone is using a virual

Beyond that, I suppose it is pretty much "plug & play" or better unplug
& ping. Go to the last router, unplug one cable, ping, if it is still
working, plug it in again and go to the next. Until you find the cable.
Then follow the cable to whereever it leads you and to the same with any
switch/hub in between.

Again, unless you have the more expensive stuff, which has a proper
management interface and tells you about what is connected on which port...


Re: Find out a device by knowing IP

Gerald Vogt wrote:
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Thanks a ton Gerald. The arp command worked. We could identify the
device and the box which is using these IP addresses.

Thanks once again for the suggestion


Re: Find out a device by knowing IP

you could use Visio (technical)Active Directory and that will draw you a map
and give you a clue where it is

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