DHCP requests

Discussion in 'Cisco' started by Andy, Aug 27, 2007.

  1. Andy

    Andy Guest

    Hi guys,

    I have changed our LAN from flat to subnetted and i am facing the
    following problem:

    When i move a user from one vlan (subnet) to another, the user keeps
    aquiring the old IP address from the previous vlan, until i remove the
    entry from the DNS and deactivate the DHCP scope. Any help would be
    highly appreciated.

    Also, can i integrate the DHCP scope on a catalyst 4500, with windows
    DNS server?

    Andy, Aug 27, 2007
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  2. Andy

    Merv Guest

    What is the topology (i.e. each piece of equipment) between the PC's
    and the DHCP server

    What are the model numbers and IOS versions running on these devices.

    Post the config of the Layer 3 device that faces the troubled PC(s)
    Merv, Aug 27, 2007
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  3. Andy

    Merv Guest

    Put a sniffer (PC loaded with Ethereal) onto the same segment where
    the DHCP server is and capture the inbound DHCP request coming from a
    troubled PC.

    Verify that the DHCP request has an giaddr field which is inserted by
    the router that performs the DHCP relay function.

    If it does have a giaddr then the problem is most likely with the DHCP

    see DHCP tutorial @ http://www.isoc.org/HMP/PAPER/127/html/paper.html
    for an
    Merv, Aug 27, 2007
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