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  • Dhcp & Vlan

    We are using a single DHCP Server for around 20 VLANs. DHCP Offers IPs According to VLAN Accuretely.
    But if i change VLAN for a machine it do not get IP address for New VLAN, it shows previously assigned IP.
    If i create reservation for client everything works fine.

    What might be the cause?

    DHCP Server Win2003 Ent R2
    Clients WinXP SP2
    Cheers!!
    MCSE 2003,MCSA- Messaging 2003, VCP

  • #2
    Re: Dhcp & Vlan

    Hi,
    Not to be a pain but did you try:
    ipconfig /release
    ipconfig /renew

    When you switch to using reservations might that force a ipconfig /release I wonder?

    If no help from above; if you plug in a terminal with no IP address into the port the original used does it pick up the correct address?
    I don't know anything about (you or your) computers.
    Research/test for yourself when listening to free advice.

    Comment


    • #3
      Re: Dhcp & Vlan

      Whenever new machine is added to any VLAN it gets IP of respective VLAN.
      the problem occurs when we change VLAN.
      Cheers!!
      MCSE 2003,MCSA- Messaging 2003, VCP

      Comment


      • #4
        Re: Dhcp & Vlan

        Can I ask are you physically unplugging a terminal from one port on a switch to another port or are you changing the ports VLAN membership?

        If you are doing either, if you restart the terminal does it act as a new machine? It gets the IP of its VLAN?
        I don't know anything about (you or your) computers.
        Research/test for yourself when listening to free advice.

        Comment


        • #5
          Re: Dhcp & Vlan

          I have a similar problem to this. A site that we have inherited has a number of VLANS that are serviced by one DHCP server. I am advised by the network guys that the VLANs are set up correctly to receive an IP address from the scope appropriate to that VLAN.

          What seems to happen is if a PC relocated from one VLAN to another, i.e. a laptop user moves from one location to another, the laptop does not pick up a new IP address that corresponds to the new VLAN. What you actually have to do, is clear the old DHCP lease for the client on the other VLAN before they are able to pick up an IP address from the correct VLAN. The same as doing an ipconfig release and renew. The server has been set up with an 8 day lease time. I am assuming that if a client goes off the network the lease will remain in DHCP until it expires - is this my problem? Do I need to shorten the lease times to account for clients moving between VLANS?

          Any advice would be greatly appreciated.

          Comment

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