How to configure DHCP server

 Introduction

Dynamic Host Configuration Protocol (DHCP) is a core infrastructure service on any network that provides IP addressing and DNS server information to PC clients and any other device. DHCP is used so that you do not have to statically assign IP addresses to every device on your network and manage the issues that static IP addressing can create. More and more, DHCP is being expanded to fit into new network services like the Windows Health Service and Network Access Protection (NAP). However, before you can use it for more advanced services, you need to first install it and configure the basics. Let’s learn how to do that.

Installing Windows Server 2008 DHCP Server

Installing Windows Server 2008 DCHP Server is easy. DHCP Server is now a “role” of Windows Server 2008 – not a windows component as it was in the past.
To do this, you will need a Windows Server 2008 system already installed and configured with a static IP address. You will need to know your network’s IP address range, the range of IP addresses you will want to hand out to your PC clients, your DNS server IP addresses, and your default gateway. Additionally, you will want to have a plan for all subnets involved, what scopes you will want to define, and what exclusions you will want to create.
To start the DHCP installation process, you can click Add Roles from the Initial Configuration Tasks window or from Server Manager à Roles à Add Roles.

Figure 1: Adding a new Role in Windows Server 2008
When the Add Roles Wizard comes up, you can click Next on that screen.
Next, select that you want to add the DHCP Server Role, and click Next.

Figure 2: Selecting the DHCP Server Role
If you do not have a static IP address assigned on your server, you will get a warning that you should not install DHCP with a dynamic IP address.
At this point, you will begin being prompted for IP network information, scope information, and DNS information. If you only want to install DHCP server with no configured scopes or settings, you can just click Next through these questions and proceed with the installation.
On the other hand, you can optionally configure your DHCP Server during this part of the installation.
In my case, I chose to take this opportunity to configure some basic IP settings and configure my first DHCP Scope.
I was shown my network connection binding and asked to verify it, like this:

Figure 3: Network connection binding
What the wizard is asking is, “what interface do you want to provide DHCP services on?” I took the default and clicked Next.
Next, I entered my Parent Domain, Primary DNS Server, and Alternate DNS Server (as you see below) and clicked Next.

Figure 4: Entering domain and DNS information
I opted NOT to use WINS on my network and I clicked Next.
Then, I was promoted to configure a DHCP scope for the new DHCP Server. I have opted to configure an IP address range of 192.168.1.50-100 to cover the 25+ PC Clients on my local network. To do this, I clicked Add to add a new scope. As you see below, I named the Scope WBC-Local, configured the starting and ending IP addresses of 192.168.1.50-192.168.1.100, subnet mask of 255.255.255.0, default gateway of 192.168.1.1, type of subnet (wired), and activated the scope.

Figure 5: Adding a new DHCP Scope
Back in the Add Scope screen, I clicked Next to add the new scope (once the DHCP Server is installed).
I chose to Disable DHCPv6 stateless mode for this server and clicked Next.
Then, I confirmed my DHCP Installation Selections (on the screen below) and clicked Install.

Figure 6: Confirm Installation Selections
After only a few seconds, the DHCP Server was installed and I saw the window, below:

Figure 7: Windows Server 2008 DHCP Server Installation succeeded
I clicked Close to close the installer window, then moved on to how to manage my new DHCP Server.

How to Manage your new Windows Server 2008 DHCP Server

Like the installation, managing Windows Server 2008 DHCP Server is also easy. Back in my Windows Server 2008 Server Manager, under Roles, I clicked on the new DHCP Server entry.

Figure 8: DHCP Server management in Server Manager
While I cannot manage the DHCP Server scopes and clients from here, what I can do is to manage what events, services, and resources are related to the DHCP Server installation. Thus, this is a good place to go to check the status of the DHCP Server and what events have happened around it.
However, to really configure the DHCP Server and see what clients have obtained IP addresses, I need to go to the DHCP Server MMC. To do this, I went to Start à Administrative Tools à DHCP Server, like this:

Figure 9: Starting the DHCP Server MMC
When expanded out, the MMC offers a lot of features. Here is what it looks like:

Figure 10: The Windows Server 2008 DHCP Server MMC
The DHCP Server MMC offers IPv4 & IPv6 DHCP Server info including all scopes, pools, leases, reservations, scope options, and server options.
If I go into the address pool and the scope options, I can see that the configuration we made when we installed the DHCP Server did, indeed, work. The scope IP address range is there, and so are the DNS Server & default gateway.

Figure 11: DHCP Server Address Pool

Figure 12: DHCP Server Scope Options
So how do we know that this really works if we do not test it? The answer is that we do not. Now, let’s test to make sure it works.

How do we test our Windows Server 2008 DHCP Server?

To test this, I have a Windows Vista PC Client on the same network segment as the Windows Server 2008 DHCP server. To be safe, I have no other devices on this network segment.
I did an IPCONFIG /RELEASE then an IPCONFIG /RENEW and verified that I received an IP address from the new DHCP server, as you can see below:

Figure 13: Vista client received IP address from new DHCP Server
Also, I went to my Windows 2008 Server and verified that the new Vista client was listed as a client on the DHCP server. This did indeed check out, as you can see below:

Figure 14: Win 2008 DHCP Server has the Vista client listed under Address Leases
With that, I knew that I had a working configuration and we are done!