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Vista/XP Wifi home network IP Address Keeps Changing for Notebook PC

Discussion in 'Networking' started by desertwind, Jun 12, 2009.

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  1. desertwind

    desertwind Thread Starter

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    I have a desktop PC running Win XP SP2 and a notebook on Win Vista Home which I have networked through a Trendnet wireless router. The desktop has Zonealarm firewall installed. I went into Zonealarm and entered the IP address for my notebook into the trusted zone and for a while evertyhing works fine. Every once in a while, though, connectivity is lost and it always traces back to the wireless IP address for my notebook being different by one digit. For example, the IP in the firewall had been set to 192.168.0.100 and so was my notebook and has been working fine. Or at least it was. This morning, the notebook IP had changed to 192.168.0.101 which of course didn't match what the firewall was looking for so no connectivity. As soon as I changed the firewall setting, voila, connectivity.

    Why does the IP address for my notebook keep randomly changing for no apparent reason? The range of IPs I've seen assigned to my notebook is always 192.168.0.100 through 192.168.0.102.

    Tawni
     
  2. sdikevin

    sdikevin

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    Jun 10, 2009
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    You have DHCP turned on. Your computer sends a request for an IP address to your router, your router give your computer an IP address. That ipaddress has a lease time. Once that lease time is up the computer gets a different IP address from the DHCP IP pool, and the IP it use to have goes back in the pool but is not used for a certian period time so there will not be IP confilics on your network.


    you need to set Zonealram to trust the NETWORK your laptop is on.
    192.168.0.0 255.255.255.0

    Your laptop will always be in that network as long as your using your home router
     
  3. JohnWill

    JohnWill Retired Moderator

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    One thing to note, you will retain the same IP address for as long as you're connected. If you're disconnected and the current lease time expires, you will then potentially get a different IP address from the router's DHCP server.

    Many routers have a MAC->IP reservation feature that will lock the IP address to the MAC address of the connecting device. You might check to see if you have that option.
     
  4. desertwind

    desertwind Thread Starter

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    Thanks for the responses, guys. John, I went into my router settings and found the option to lock the ip address to the MAC id of each of my PCs. I guess only time will tell whether this worked. Thanks for the tip. Just in case anyone else does this, remember to reboot your router after making changes. Otherwise, you won't be able to connect to the internet even though all your connections appear operational.

    Here's one other related question: Can I now disable the DHCP option? I wasn't sure if this would manually require me to log in or something to connect.

    Tawni
     
  5. JohnWill

    JohnWill Retired Moderator

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    No, you want to leave DHCP enabled.
     
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