Whenever I hibernate my laptop at home, go to the office an wake it up there I get an IP address conflict warning. IP is configured by DHCP (without any MAC binding) at both places so I think it would work ok if the interface is brought down before hibernation and up (effectively reinitializing the stuff from DHCP safely) after waking up. Can I configure Windows 7 (or use a 3-rd party utility) to achieve this effect?

I usually switch WiFi on/off manually using the key I have on the laptop case but some times I forget to do so and this disrupts the boss's PC Internet connection.

  • Not sure how you'd go about it exactly, but what about a batch script that changes the registry values that control the devices and then runs the hibernate script.
    – Jonah
    Jul 23, 2014 at 13:08
  • Why don't you change your home router LAN DHCP range so it's out of the range of your work network... it's a very simple process to change the home network, rather than your work one... change the range to, say, 192.168.3.x - if your work range also does this then change to 192.168.4.x or 192.168.5.x. You then shouldn't get the conflict problem and won't need to worry about things like scripting and registry changes etc.
    – Kinnectus
    Jul 23, 2014 at 13:15

2 Answers 2


Your issue is that DHCP leases don't expire immediately after your computer disconnects from the network. You really need to look into one of the following, for easiest resolution:

  1. Set your home LAN to use a different subnet from your work network. This is the easiest way to eliminate overlap, and you shouldn't have issues since you're using DHCP everywhere. There should be guides to doing this for most routers online.

  2. Set a manual IP address (either through Windows TCP/IP settings, or through MAC address binding on your home router) for your machine in a part of the work LAN subnet that isn't part of the DHCP pool, and is also unused. You'd need to ask your work network admin, but there are generally ports saved for this kind of thing.

I'd go with #1, it should have the lowest difficulty, and will certainly resolve your issue.


You can attach tasks to events in the system event log. While observing the event of an IP conflict (4199) you may start a small script doing

ipconfig /release 
ipconfig /renew

executed as administrator.


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