Configuring the DHCP Service

Configuring the DHCP Service:

After you install and start the DHCP service, you must create a scope (a range
of valid IP addresses that are available for lease to the DHCP clients). Each
DHCP server in your environment should have at least one scope that does not
overlap with any other DHCP server scope in your environment. In Windows 2003,
DHCP servers within an Active Directory domain environment must be authorized to
prevent rogue DHCP servers from coming online and authorizing a DHCP Server.

When you install and configure the DHCP service on a domain controller, the
server is typically authorized the first time that you add the server to the
DHCP console. However, when you install and configure the DHCP service on a
member server, you need to authorize the DHCP server.

Note A stand-alone DHCP server cannot be authorized against an
existing Windows Active Directory.

To authorize a DHCP server:

1. click Start, click Programs, click
Administrative Tools, and then click DHCP.

Note You must be logged on to the server with an account that
is a member of the Enterprise Administrators group.

2. In the console tree of the DHCP snap-in, select the new DHCP server. If there
is a red arrow in the bottom-right corner of the server object, the server has
not yet been authorized.

3. Right-click the server, and then click Authorize.

4. After a few moments, right-click the server again and then click
Refresh. The server should display a green arrow in the bottom-right
corner to indicate that the server has been authorized.

To create a new scope:

1. Click Start, click Programs, point to
Administrative Tools, and then click DHCP.
Note In the console tree, select the DHCP server on which you
want to create the new DHCP scope.

2. Right-click the server, and then click New Scope. In the New
Scope Wizard, click Next, and then type a name and description
for the scope. This can be any name that you choose, but it should be
descriptive enough to identify the purpose of the scope on your network. For
example, you might use Administration Building Client Addresses.

3. Type the range of addresses that can be leased as part of this scope, for
example, a starting IP address of 192.168.100.1 to an ending address of
192.168.100.100. Because these addresses are given to clients, they should all
be valid addresses for your network and not currently in use. If you want to use
a different subnet mask, type the new subnet mask. Click Next.

4. Type any IP addresses that you want to exclude from the range you entered.
This includes any addresses that may have already been statically assigned to
various computers in your organization. Click Next.

5. Type the number of days, hours, and minutes before an IP address lease from
this scope expires. This determines the length of time that a client can hold a
leased address without renewing it. Click Next to select
Yes, I want to configure these options now, and then extend the
wizard to include settings for the most common DHCP options. Click Next.

6. Type the IP address for the default gateway that should be used by clients
that obtain an IP address from this scope. Click Add to place
the default gateway address into the list, and then click Next.

Note When DNS servers already exist on your network, type your
organization's domain name in Parent domain. Type the name of
your DNS server, and then click Resolve to ensure that your
DHCP server can contact the DNS server and determine its address. Then click
Add to include that server in the list of DNS servers that are
assigned to the DHCP clients. Click Next.

7. Click Yes, I want to activate this scope now, to activate
the scope and allow clients to obtain leases from it, and then click
Next. Click Finish.

Troubleshooting:

Clients are unable to obtain an IP address
If a DHCP client does not have a configured IP address, it generally means that
the client has not been able to contact a DHCP server. This is either because of
a network problem or because the DHCP server is unavailable. If the DHCP server
has started and other clients have been able to obtain a valid address, verify
that the client has a valid network connection and that all related client
hardware devices (including cables and network adapters) are working properly.

The DHCP server is unavailable
When a DHCP server does not provide leased addresses to clients, it is often
because the DHCP service has failed to start. If this is the case, the server
may not have been authorized to operate on the network. If you were previously
able to start the DHCP service, but it has since stopped, use Event Viewer to
check the system log for any entries that may explain the cause.

Note To restart the DHCP service, click Start,
click Run, type cmd, and then press ENTER.
Type net start dhcpserver, and then press ENTER.