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DHCP Help Needed

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by jlbpotter

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I have a windows NT 4 domain that I am in the process of migrating to Windows 2000. I currently have a W2K member server that is acting as my DHCP server. Everything is working great. I have added another IP subnet that is on the same physical network and am trying to configure it in DHCP. My current scheme is 192.168.0.1/255 with the default subnet. The DHCP server hands out these IPs fine. I added another scope to my DHCP server consisting of 192.168.1.1/255 with the default subnet. I have activated the scope but when my original scope hands out all of the leases, the next machine that comes online fails to get an IP address from DHCP. Is there some other configuration that I am missing? Thanks in advance.

6 replies

by timwalsh

I fear you are going about this in the wrong way. I assume you wanted to add the second scope because the first scope didn't provide enough IP addresses for your network.

You have 2 choices:

Once you create the second scope, the two scopes must be joined into a superscope.

Create a single scope with enough IP address range to handle your network:

(NOTE: the following subnets are calculated using the Cisco method)

Network address: 192.168.0.0
Subnet mask: 255.255.192.0

This yields two subnets with approximately 16,000 hosts in each subnet.

Subnet 1: 192.168.64.0 Mask: 255.255.192.0
First host: 192.168.64.1
Last host: 192.168.127.254
Broadcast address: 192.168.127.255

Subnet 2: 192.168.128.0 Mask: 255.255.192.0
First host: 192.168.128.1
Last host: 192.168.191.254
Broadcast address: 192.168.191.255

Does this waste a lot of addresses? YES, but who cares as you have a private network anyway. And this will give you LOTS of room for expansion.

If you want a different addressing scheme (smaller subnets maybe), using other subnet masks will yield more subnets with fewer available hosts in each subnet.

Hope this helps.

by jlbpotter

I need to use the current configuration that I have. I am not wanting to change my router info and I have a couple of WAN links that are connected to other domains. So are you saying that all I need to do to make this work is create the two scopes and join them in a superscope? Thanks for your time.

by armylanman

You need a superscope as mentioned above.

You define a superscope as a collection of different scopes. That way when the server exhausts one scope of addresses it knows to start handing out addresses in the other scope.

Just define a superscope containing the two scopes you have defined.

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