DHCP Scope problem

[jasonb007]

We have a school server setup with an IP of 172.24.53.2 and a DHCP range setup from 172.24.53.10 to 172.24.53.126, Subnet 255.255.255.128. The lease is set to 8 hours as we get close to running out of IP addresses when staff bring in there wireless laptops. We need to add some more PC's to the network which will push us over the number of IP addresses available. What's the best way to increase the range? There are managed network switches, printers, wireless points, projectors on the LAN so don't want to have to reconfigure all the devices if possible. The school LAN is setup as 2 VLANS, one for admin, the other for curriculum and the issue is on the curriculum side. The gateway/router is setup as IP 172.24.53.1 and Subnet
255.255.255.128 by the local authority so we can't alter this (and they wont change it anyway!)

One thing i experimented with (on a test network, not live!)is creating a superscope (because thats what 2003 server prompts me to do when I enter the large range) that includes a scope ranging from 172.24.53.10 to 126 and another scope from 129 to 250. But anything that gets an IP from the "secondary scope", 129 or above, can't ping the server or see shared resources. If I release the IP and make it get one from the 10 to 126 range, I can ping and see shared resources.

Someone mentioned I should add a static route to the second DHCP scope so it can see the first scope. Can anyone advise how I can do this in Windows Server 2003 or an alternative solution.

Other points to mention, the server has one NIC but I can add another if required.

Many thanks.

 

[cajuntank]

VLANs are where you need to be at. Create another VLAN, name it for curriculum and your original for administration. You could also change the mask to that of a class C to give you more addresses for administration as well. So for example your addressing might look like:

172.24.53.0/24 for administration VLAN and
172.24.54.0/24 for curriculum VLAN

You need a L2 managable switch to have your different
VLAN(s), but you'll need a L3 switch or router to be able to route between the two.

Your DHCP server could hand out addresses for both subnets granted that you specify the server's address as the "helper address" in your switch for that other VLAN interface.

Hope I could help.

 

[jasonb007]

Thanks for your reply. Unfortunately, we can't create another VLAN, the school LEA wont do this and they wont give us the username and passwords of the switches/routers so we can do it ourselves (we are also there competition)!! Any other suggestions.

 

[baddos]

Why is the netblock so small? You are using a private address, assuming this is just for random hosts why not add another router to the mix and create a new netblock and use NAT. Does the "local authority" need direct access to hosts on this network?

 

[jasonb007]

Yes, the local authority does need direct access to all PC's on the network for tasks such as antivirus monitoring. I think i might just have to get them in to change the subnet mask from a 255.255.255.128 to a 255.255.255.0.

 

[baddos]

Yeah if they need direct access, you'll just have to get them to resubnet you. It shouldn't be a problem if you don't have a lot of static IP addresses. Probably just as simple as configuring the router and server and it's dhcp scope. Your local authority will have to be involved for sure though and have their approval.