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  1. #1
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    Renewing IP Address

    My home network has a desktop and a laptop and a ReplayTV (like TiVo) on it. I have turned off the DHCP function in the router and installed a DHCP Server in the desktop. The DHCP Server is set to assign IP addresses that do not expire. The laptop is set to to get its IP address from the DHCP Server.

    Will the laptop ask for a new IP address each time it is rebooted in these circumstances? If not, how do I force the laptop to get a new IP address from the DHCP Server.

    Thanks,
    Bill

  2. #2
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    Re: Renewing IP Address

    The laptop probably will not get a different IP address at each boot. Why is this a big deal? If your router has a firewal adn you are running firewall software you should not have much to worry about.

    Joe
    Joe

  3. #3
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    Re: Renewing IP Address

    No, I'm not worried about anything except to learn what I can in this area and also satisfy myself that the DHCP Server really is doing its job properly. The thing that has puzzled me is the laptop has the same IP address all the time even though it is not the lowest address available in the range defined in the DHCP Server. I'm just puzzled if the IP is not being renewed or if the DHCP Server keeps assigning the same address.

    Is there a way to force the DHCP Server to supply a new address to the laptop?

    Thanks,
    Bill

  4. #4
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    Re: Renewing IP Address

    On the laptop type the following commands to a command prompt.

    <code>IPCONFIG /ALL</code>
    note the dates and times for Lease Obtained and Lease Expires
    <code>IPCONFIG /RELEASE</code>
    <code>IPCONFIG /RENEW</code>
    <code>IPCONFIG /ALL</code>
    note the new dates and times, showing that the DHCP server has functioned correctly.

    It is very likely that the DHCP Server will grant the laptop the same address as it was previously using, if you want to change this then change the address pool in the DHCP Server after the laptop releases and before it renews.

    StuartR

  5. #5
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    Re: Renewing IP Address

    Stuart,

    I actually went through that command sequence yesterday and totally overlooked the date and time information that it gives! <img src=/S/blush.gif border=0 alt=blush width=15 height=15> The DHCP Server did do the job it is supposed to do. I don't actually have any problem with the IP the laptop was given, I had just expected it to be given the lowest unused address in the range that is available and it didn't do that.

    I imagine I should change the lease time back to a reasonable time so the laptop will not have such a long lease time too. Do you know if it would work correctly with the extremely long lease time for the present IP address if I took the laptop to a wireless hotspot and tried to connect there? Would it renew its IP address as it should when I booted up in that environment? I can't actually try it yet because this laptop does not have wireless capability but I'm planning to get a new one very soon.

    Thanks for helping.
    Bill

  6. #6
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    Re: Renewing IP Address

    The long lease shouldn't be a problem if you shut the computer down and restart it when changing networks. If you just hibernate then this can cause problems, and sometimes I have to disable and then re-enable the LAN or Wireless connection to get it to work properly.

    StuartR

  7. #7
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    Re: Renewing IP Address

    Thanks for explaining it, Stuart. I think I'm in good shape now.

    Bill

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