Question about subnetting 1

[mkirros]

We (relatively small non-profit) have a network with a single Win2000 AD Server acting as the PDC and about 40 workstations. The PDC also acts as the DNS Server, and the DHCP and routing is done by our DSL modem/router. Currently all of the workstations are on the same subnet (255.255.255.0) using 192.168.0.x addresses.

I'd like to subnet the network to separate out a couple of groups of workstations that should logically be grouped together but separated from each other and am wondering whether additional hardware will be necessary. Some employees will need to have access information on all subnets, but most will not. I'd appreciate any guidance you might have. Thanks in advance.

 

[cyberspace]

I think firstly the most important question would be...what is the minimum amount of hosts required on any one subnet?

I can't see why you would need additional hardware, however as far as the DHCP is concerned, it won't be as simple as just dynamically assigning an address to any host that needs one anymore because only a certain range will apply to a particular subnet mask (not 100% certain on the implications of that however, perhaps somebody can verify).

Also worth pointing out, is that VLAN's would also be a suitable solution for what you want to do, however this will have hardware implications!

 

[mkirros]

The smallest subnet would have about 5 computers, the largest about 30. Hardware implications could be fairly major for us, because our budget is pretty tight, so any solution that doesn't require adding hardware would be preferred.

 

[cyberspace]

Well that's doable - but its a squeeze with standard subnetting. And i'm hoping you won't need any more than 6 subnets!

I am unsure of your knowledge of subnetting so please forgive me if i'm telling you what you already know!

You can have 6 subnets, with 30 hosts per subnet.

The only potential problem there is that you will be unable to expand the largest subnets. VLSM could be used if address space is an issue, although again this would have hardware implications.

You will need to configure routing between the subnets - however I am not sure how to allow acces to other subnets by users on a particular subnet, where there are also users on the same subnet that are not allowed.