Thursday, 15 January 2009

Building a test lab

Thanks to the Technet subscription that work has provided for me, I'm now in a position to build my own test Windows network. The purpose of this is to help me get a grip on Windows Server 2008, some Active Directory, Terminal Services etc., and potentially some other non-MS tech such as Citrix XenDesktop [Express].

I've been thinking through the planning of this test lab and recognise that I need to create a network. I can either create a new, completely virtual network and put my VMs on it, routing this to my physical network using a dual homed VM appliance, or I can create the test network in a different address range as my "live production" network and assign the IP addresses so that they don't overlap.

The latter seems the easiest way of doing it (although I may be proven wrong when it's built!).

So, assume my local network is (it's not, but I'm not stupid enough to put my real subnet on the 'net!). I'm going to slice up the subnet as follows: - = static range for production network - = DHCP range for production network - = static range for test lab network - = DHCP range for test lab network

How do I determine whether a plugged in device gets a production or test DHCP address? Ultimately it will depend on which DHCP server responds, but the reality is that it shouldn't really matter. Both servers will allocate an address that is routable to the Internet and will resolve the DNS. For anything that will be permanent, I'll allocate a static IP anyway.

My production network has the DNS suffix of, and I contemplated creating the Active Directory as a sub-domain ( I think that it will be easier though if I simply create a new domain (e.g., and manually create a DNS forwarder to when appropriate. This keeps the production network (primarily non-Windows based Solaris, Linux and Mac OS X with a non-domained Vista) from interfering, or depending on, the test lab.

If either of my readers(!) spots anything obviously wrong here, please let me know!


pmatz said...

Just one thing. The 'subnets' you say are: - - - -

am i missing something as these don't seem to fall into the 'standard' subnets of a VLSM or normal subnet.
wouldnt it be

or something like this? I always thought subnets could only be divided up by powers of 2 eg 4,8,16,32,64 etc... and with VSLMs you can drill down to have different sized subnets off one network?

might just be me though!

JR said...

Yes - technically they're not different subnets. In fact, the address is

I've simply found a way of hosting two logical networks (my main network and DNS zone, and the test lab network and DNS zone) so that they don't collide.

The problem with creating two separate networks using VLSM is that I would need some way of routing between them - not rocket science, but just an extra hassle that I don't want to worry about.