DHCP server

TCP/IP has become for more and more installations the preferred network
protocol, also pushed by the explosive growth of the Internet, which is
based on TCP/IP.

When using a network with only Windows95 and WindowsNT4 based systems,
you will have to assigned the IP-addresses manually (Windows98 includes an
IP-Auto-Configuration system), but more and more server-systems offer the
automatic assignment of IP-addresses via:
DHCP (Dynamic Host Configuration Protocol)

The installation of the DHCP-server on Windows NT4 server (the DHCP-server
is NOT included in Windows NT4 workstation ) is very simple:

In the Network-configuration,
tab: Services, click on "Add"
and then select:
"Microsoft DHCP Server"

The following notice will be displayed:

The system running the DHCP-server (distributing IP-addresses to other systems)
itself MUST use a static IP-address (manually assigned) , it can NOT request
to receive an IP-address from any DHCP-server (itself or another DHCP server).

Like after all changes to the network configuration, you have to reboot:

	Although the DHCP-server is listed as a Networking service, it is NOT configured from the Network applet (the Properties button is grayed out)
	The "DHCP - Manager" has been added to the menu for the "Administrative Tools"

	You need to define now a range of IP-addresses to be distributed. This range is called: "Scope". To be able to define Scope, click first on the entry "Local Machine" to expand the entry, the "+" -sign needs to change to the "-"-sign.
	Only then you are able to select from the menu: "Scope" the option "Create"

You assign the range of IP-addresses to be assigned by DHCP-server
( in the example: all IP-addresses between 102.54.107.1 and 192.54.107.49):

usually, an IP-address is NOT assigned permanently, but only for a limited
time, called the "Lease Duration".

On selected the "OK"-button, you will be asked on whether to activate
the scope, select "Yes":

	The yellow light-bulb indicates, that the scope is now active and that the DHCP-server is ready to assign the IP-addresses.
	To display the IP-range ("Scope") for viewing/editing, select from the menu "Scope" the option "Properties"

In the Network-configuration,
select the properties for the
TCP/IP-protocol and just make
sure, that it defines to
"obtain an IP address automatically"

To verify the assigned IP-address on a Windows95/98 system, run the
"WINIPCFG" program (usually from the RUN-menu)(On Windows NT, use IPCONFIG):

In this example, DHCP assigned the IP-address 192.54.107.1.
But there is no "Default gateway" defined !

TCP/IP requires more than just the IP-address, for communication outside
the local network-cable (the local "subnet"), it needs to know the IP-address
of the Gateway (also called Router).
DHCP can be configured to provide also this information to the clients:

make sure, that your Scope is selected
(highlighted in blue), then select from the
menu: "DHCP Options", then "Scope"

	From the list of "Unused Options", select "Router", then use the "Add"-button.
	Once the "Router" is an "Active Option", click on the button "Value" to define the IP-address for the Router.
	On the expanded Windows, click on "Edit Array", allowing then to enter the IP-address of the Router, then select the "Add"-button to get the new values displayed in the list of IP-addresses. Press "OK" to exit this window.
	The IP-address of the Router is displayed. Press "OK" to close the DHCP-Options window.

When now checking on Windows95/98 with WINIPCFG:

the IP-address for the "Default Gateway" is defined.

If your configuration requires the use of WINS, it can be also configured
as an option of the DHCP-server.

	To view the list of IP-address already assigned, select from the menu: "Scope" the option "Active Leases"
	In this example, 192.54.107.1 is assign to a LAN user, while 192.54.107.2 is assigned to the Modem to handle incoming RAS TCP/IP-connections.