How to install and configure a DHCP server
Host Configuration Protocol (DHCP) is an invaluable service when you have a
network larger than a handful of computers. It’s also a standard component of
enterprise networks and sub networks. Microsoft
Windows Server 2008’s built-in DHCP server allows Windows machines (and
any other TCP/IP-based machines and devices) to obtain their IP addresses and network
settings automatically, which can vastly simplify network configuration. In
this document, we’ll discuss how to install and configure a DHCP server in
Windows Server 2008, and we’ll explore some of the advanced features DHCP has
Create a plan
Before you configure your DHCP server, it is a good idea to have all your
ducks in a row. Prepare and have all the necessary information up front before
sitting down and configuring your server. For example, you may need to know:
- The scope of IP addresses that your server will manage (e.g., 192.168.1.50
- Which machines require static IP addresses (i.e., those machines such as
servers and routers that will not use DHCP to receive their IP addresses but
will be set manually).
- Which network information you want to send out to DHCP clients when they
get their IP addresses (e.g., the addresses for your default gateway, DNS
servers, and WINS servers).
It is much easier to configure your DHCP server with this information in hand
rather than scrambling for it at implementation time.
Installing a DHCP server in Windows 2008 is a snap. They created a very
simple wizard that walks you through the entire process. Follow me on this
To install a DHCP server from the Control Panel, follow these steps:
- From the Start menu, select | Control Panel | Administrative Tools |
- Expand and click Roles.
- Choose Add Roles and follow the wizard by selecting the DHCP role .
- A new DHCP wizard appears to help you configure a DHCP server.
In the previous release of Windows, a wizard did not appear to walk you
through creating a DHCP server. Windows Server 2008 has really simplified this
process by allowing you to configure a DHCP server in roughly seven steps. Of
course, you can still manage your DHCP server from the DHCP Microsoft Management
Console (MMC) snap-in or delete and create scopes on the fly.
Let’s continue on through the wizard. Your network cards and static IP
addresses are automatically detected and you can choose how DHCP will service
clients on different subnets.
On the next window you can specify the applicable DNS server(s) to be
used with DHCP when an address is assigned. Here displays where you would enter
the applicable WINS servers if you require it on your network.
When you create a scope, you must select the range of IP addresses and you
must specify the appropriate scope options to include. These options are what we
were referring to above when we mentioned that you can assign other network
information to your clients at the time they are given an IP address.
There are two types of scope options: Global and Scope. Global options are
propagated to all the scopes that you create on that DHCP server, while Scope
options are only for the individual scope that you are working with.
For example, if you have different scopes for several different subnets and
each subnet will have a different default gateway but will share the same DNS
servers, you would want to set the DNS servers as a Global option while the
default gateways would be set separately in each scope as a Scope option.
On the DHCP scope window, you will create your scope. Depending on the size
of your network and the amount of users that will be assigned IP addresses, some
thought must be given to the parameters of your scope selections. In my example,
I created a simple scope.
The subnet type dropdown allows you to choose wireless as well. It defaults
to 24 hours. If you want to activate the scope when the wizard is complete,
click the Activate this scope checkbox. If you leave it empty, you must activate
the scope in the DHCP Microsoft Management Console (MMC) snap-in.
With Windows Server 2008, if you have a router that supports and is
configured to take advantage of IPv6, you can enable this functionality on your
Authorizing the DHCP server and activating scopes
In previous versions of Windows Server, you had to install and configure your
DHCP server and then authorize it in the DHCP MMC
snap-in. Authorizing your DHCP server allows you to prevent hackers from
configuring rogue DHCP servers. In Windows Server 2008, you have the ability to
either authorize the server in the Wizard or authorize it after the fact in the
You are now ready to review and confirm your settings before applying your
Once you have installed the DCHP server, you can manage it from the DHCP MMC
snap-in located in Administrative tools. On this screen you can create
additional exclusions and reservations.
In addition to specifying exclusions, you can add reservations to your DHCP
server. By adding a reservation, you ensure that a machine always receives the
same IP address from the DHCP server.
- Right-click on Reservations and choose new reservation.
- Enter a friendly name for the reservation and the IP address you want to
assign to the computer or device.
- Enter the MAC address of the computer or device. (For Windows machines,
you can find the MAC address by running ipconfig/all from the
command prompt of the machine.)
- Enter a description and then choose the following reservation type: DHCP,
BOOTP (going across a router), or both, as shown in. Click Add.
In addition to specifying reservations, you can add exclusions to your DHCP
server. By adding exclusions, you ensure that machines never receive a DHCP
lease for that range of IP addresses. This is very useful to block IP addresses
for your servers and routers.
In order to add Exclusions, right-click on Address Pools and choose New
After configuring DHCP, the easiest way to troubleshoot it is to use Ipconfig
from a command prompt. To view all TCP/IP information on a machine just type ipconfig/all.
To release a DHCP lease, type ipconfig/release; to renew a lease,