Computer has two entries in DHCP / two MAC addresses

Discussion in 'Windows Networking' started by NZSchoolTech, Jul 19, 2007.

  1. NZSchoolTech

    NZSchoolTech Guest

    I have a strange thing happening with one of our laptops. In DHCP it has
    two distinct leases created about an hour apart, with two IP addresses
    and two MAC addresses.

    The ARP table for that server doesn't show any entries for that computer
    at all, not either of those addresses.

    In what circumstances could a computer change its MAC address by itself?
    I presume that happening would be the reason why DHCP has re-registered
    it with the same name but a different IP address.

    Windows XP SP2 and all updates.
    NZSchoolTech, Jul 19, 2007
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  2. You probably checked this already but I thought I'd throw it out there
    anyway... Do you have both the ethernet and the wireless connected? -as each
    of these has its own MAC address.

    Coraleigh Miller
    Coraleigh Miller, Jul 20, 2007
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  3. hi,
    it could be more possibilites not necessary in that order :):
    1. another computer/device with the same name in your LAN but in a different
    VLAN, behind the router etc. have a software with mac address spoofing -are plenty of that on the
    net ussusally used on internet connection with MAC address counter for
    3. it have another nic virtual or not (wireless, VLAN etc)
    Dragos CAMARA, Jul 20, 2007
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