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Unidentified DHCP client

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  • 04-02-2007 3:12pm
    #1
    Orion
    Closed Accounts Posts: 12,807 ✭✭✭✭


    This should be a quick one for an expert.

    I have a Linksys WRT54G. My main PC uses a static IP and any other devices use DHCP. Currently I only have 2 other devices connected - my XBox and my sister's laptop. But in the DHCP table on the Linksys I have 3 assignments. I can't for the life of me figure out what this device is. The MAC address isn't the one from the Linksys or the Zyxel modem.

    Any ideas?


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    #2
    KdjaCL
    Closed Accounts Posts: 20,346 ✭✭✭✭KdjaCL


    Is it your pcs network card?


    kdjac


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    #3
    Orion
    Closed Accounts Posts: 12,807 ✭✭✭✭Orion


    Should have said that - no it's not.


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    #4
    tuxy
    Closed Accounts Posts: 14,983 ✭✭✭✭tuxy


    Your neighbour?


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    #5
    mastermind2005
    Banned (with Prison Access) Posts: 339 ✭✭mastermind2005


    just backup the settings of the router and hit the reset button on the back, entries often get stuck and this could be a device that connected some time ago, also try changing your key as it could be ur neighbour, any chance the laptop is connected with cable and wifi ?


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    #6
    Cake Fiend
    Registered Users Posts: 5,335 ✭✭✭Cake Fiend


    To see if it's still in use, ping the IP - if it doesn't respond, check your arp table to see if the MAC at least shows up.

    Getting a bit more info about the device may help you work out what it is - stick the first three bytes of the MAC address into google and see if you get a manufacturer. You might be able to narrow down what type of device (router, pc, etc) it is from the manufacturer.

    Download nmap and scan the IP with OS detection on. You might be able to narrow down further what the device is, and what OS it's running (plus you'll get an idea of what kind of services might be running on it if the scan is successful).

    If it's an unfirewalled Windows machine, try a nbtstat -A to see if you can get a hostname for it. This might give a further clue as to what it is and potentially who owns it.

    I personally would then try to get into the machine and get as much info from that as possible, but you'll have to figure that one out yourself ;)


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    #7
    Snaga
    Registered Users Posts: 1,562 ✭✭✭Snaga


    If you know what the mac-address is - grab the first 6 characters (Known as the OUI) and search for them on this page...

    http://standards.ieee.org/regauth/oui/index.shtml

    Enter the first 6 characters in the format XX-XX-XX and it will tell you the manufacturer of the device.

    It should narrow down your search a bit.


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    #8
    Static M.e.
    Registered Users Posts: 3,088 ✭✭✭Static M.e.


    Post the Mac address


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