I need to force a DHCP renewal on all my clients (to make them point to my new DNS server).
Some of them have about 4 days left in their leases. Can I just delete the leases from the server? Will this force them to check in to DHCP again and grab another lease or is this a bad idea?
That's a bad idea. They won't try and renew the lease until it is expiring. Deleting the lease will cause other machines to be able to get that IP. What you want is either to run ipconfig /renew via psexec or to script the renew in PowerShell and run it remotely.
Alternatively, if the users reboot they should get the new configuration options.
I'm using Windows Server 2003 along with MS's DHCP server. We're making some changes in our environment that we'd like to phase in - these changes will require a different default route, perhaps different DNS servers. All of our clients are Windows - 2000, XP, Vista.
We'd like to find a way to say "these machines will get THIS default route/DNS, and that set of machines will get another set."
The DHCP "User Class" feature would seem to be a way to handle this, but I can't find anything about how to centrally assign the "User Class" for a given machine centrally. Everything I've found refers to issuing an ipconfig command on a given machine to change the user class. Is there a different way?
I suppose that I could arrange it that machines in particular group run a script which issues that command - but is it persistent across boots? The script wouldn't be run until the machine has a DHCP address and connects to the domain, so would it work for the next boot/DHCP renewal?
I don't know of a way that doesn't use a script.
I believe the solution is to configure the script to run at startup. It is not persistent across boots so you'd have to run it every time at startup.
C:\>ipconfig /setclassid "Local Area Connection" MyNewClassId
Windows XP IP Configuration
DHCP ClassId successfully modified for adapter"Local Area Connection"
My sense is that a more robust way of handling the issue would be to use MAC address reservations.