Can't update Subnet in DHCP

Create a new scope and then delete the old.

You are trying to create a scope which is included in the previous one, or you are creating a scope in the same network. This is not allowed!.
2 options:
1.- Delete first the scope and start creating a new one.
2.- Setup a new DHCP server (no more than 10 minutes) on another server, define here the new scopes for yopur clients, keep both of them for some days, and then remove the scope from the original server.

The fastest way is to delete first the scope and create a new one. If possible, do this while no users are logged on so when they do, they will all pick up the change.

Hi Wanna,
What is the IP Address & Subnetb Mask of your Server ?
1. First make sure all user systems are switched off.
2. change your Server's Subnet Mask to 255.255.255.0 keeping the IP as it is (say 192.168.15.2).
3. Now make similar subnet changes on all systems & servers that need a static IP (till 192.168.15.20). I assume that you have 20 systems that need 20 static IP address.
4. Now on your DHCP server, from DHCP Manager, delete the current scope & create a new one.
5. Here give the scope as 192.16.8.15.20 to 192.168.15.254 with subnet as 255.255.255.0.
6. Start this DHCP scope & start one Client system & check in command prompt.
On Win9x - C:\>winipcfg.exe &
On Win 2K / NT - C:\>IPConfig.exe

Here release & renew the IP and check for the new IP address and subnet.
Akash

First your server needs to have a class C address. If you can't install a second network card in it, then multi-home the server by adding a second address (the new class C one). Be sure to specify your new default gateway as a class C gateway. Finally, make sure your router is configured to route between your new class C address scheme and your existing class B scheme.

1. Define your Class C subnet in DHCP server.
2. Deactivate your class B subnet. Over time your users will be migrated to the Class C network.

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