After Installing the DHCP

7/29/2019 After Installing the DHCP

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Afterinstalling the DHCP-server, you will need to configure it before you can use it:

Select "DHCP" , which is part of the Windows menu "Administrative Tools". In the left

plane, you will see the name and IP-address of the DHCP-server.

After installation, a DHCP server is not authorized. Do not forget this later ! (see below

)

You need to define the range ofIP-addresses to be assigned (=distributed) by the DHCP-server. A definition of a range of IP-addresses (with or without additional options) is

called a "Scope": select your DHCP-server and then either with a right-click or from the

menu "Actions" select to define a "New Scope":
http://www.windowsnetworking.com/j_helmig/w2kdhcpi.htmhttp://www.windowsnetworking.com/j_helmig/w2kdhcpc.htm#authorizehttp://www.windowsnetworking.com/j_helmig/tcpip.htm#ip-addresshttp://www.windowsnetworking.com/j_helmig/w2kdhcpi.htmhttp://www.windowsnetworking.com/j_helmig/w2kdhcpc.htm#authorizehttp://www.windowsnetworking.com/j_helmig/tcpip.htm#ip-address


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Up comes the Wizard select "Next"

Define a name for your scope continue with "Next"


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Define the range of IP-address and thesubnet-mask. Select a range, which does not

include the IP-address of the server itself or any other device with a manually assigned

IP-address (like: network printers). Although you could exclude them in the next step,usually a range is reserved for such manually assigned addresses and then the rest (in this

case: 100 - 199 ) is given to the DHCP-server for automatic distribution.

If you could not define separate ranges for manually assigned and DHCP-assigned IP-

addresses, then you could here define IP-addresses or ranges of IP-addresses to be

excluded: not to be used by the DHCP-server.
http://www.windowsnetworking.com/j_helmig/tcpip.htm#subnet-maskhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#subnet-maskhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#subnet-maskhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#subnet-mask


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Typically, an IP-address is assigned (= "leased" ) for a limited time. This avoid runningout of addresses, when visitors to you office connect to the network and get an IP-address

assigned. Without a time-limit, such an IP-address could not be reused. usually, 8 days is

a good choice and will ensure that people every day in the office will continue to use thesame IP-address once assigned to them, since their systems will in time extend the

"lease". And if they come back from a 2 week vacation and the "lease" has expired, then

the DHCP-server will assign a new IP-address to them.


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In addition to the IP-address and Sub-Netmask, a DHCP-server can also be use to defineother TCP/IP configuration items on the Client systems.
http://www.windowsnetworking.com/j_helmig/tcpip.htm#ip-addresshttp://www.windowsnetworking.com/j_helmig/tcpip.htm#subnet-maskhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#ip-addresshttp://www.windowsnetworking.com/j_helmig/tcpip.htm#subnet-mask


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Is your office network part of a larger company Wide-Area

network (WAN )? Then you need to configure the client computers with the IP-address of

the Gateway (or Router) to be able to communicate with systems on the WAN. Enter theIP-address and then click on "Add" to enter the address to the list of Gateways.

Are you using a WAN and need to help your clients to locate the IP-addresses of servers

(like WebServers) on the WAN? Or do you intend to have clients connected to the

Windows2000 server via the new: "Active Directory" method? Then you must configure

the clients for use of a DNS-server. Enter the name of your server and the IP-address andclick on "Add" to enter the value on the list.
http://www.windowsnetworking.com/j_helmig/tcpipwan.htmhttp://www.windowsnetworking.com/j_helmig/tcpipwan.htmhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#gatewayhttp://www.windowsnetworking.com/j_helmig/tcpipwan.htmhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#dnshttp://www.windowsnetworking.com/j_helmig/tcpipwan.htmhttp://www.windowsnetworking.com/j_helmig/tcpipwan.htmhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#gatewayhttp://www.windowsnetworking.com/j_helmig/tcpipwan.htmhttp://www.windowsnetworking.com/j_helmig/tcpip.htm#dns


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You can also configure the WINS server address


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You need to activate the scope, (which you can do later with a right-click on the scope

and selecting: "Activate"/"Deactivate" :)

Finished.

You still have to "Authorize" the DHCP-server: select the server and either right-click orfrom the menu "Action" select "Authorize" :


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Note: on my system, I had to close now the DHCP-windows and open it up again to see,

that the DHCP-server is now "Running" :

a quick check on the "Scope Options", which we have configured already:


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If required, you can change or add the options of the scope.


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You can configure in the "Properties" of the scope, tab: DNS, that once the DHCP-server

has assigned an IP-address the address will be updated in the DNS-server, allowing now

other systems on the network to locate your system:

Once the DHCP-server is configured and authorized and the scope is activated, IP-

addresses will be distributed . You can then view the list of assigned IP-addresses.
http://www.windowsnetworking.com/j_helmig/w2kdhcpd.htmhttp://www.windowsnetworking.com/j_helmig/w2kdhcpd.htm


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server assigns a client an IP address taken from a predefined scope for a given amount of

time. If an IP address is required for longer than the lease has been set for, the client mustrequest an extension before the lease expires. If the client has not requested an extension

on the lease time, the IP address will be considered free and can be assigned to anotherclient. If the user wishes to change IP address then they can do so by typing "ipconfig

/release", followed by "ipconfig /renew" in the command prompt. This will remove thecurrent IP address and request a new one. Reservations can be defined on the DHCP

server to allow certain clients to have their own IP address (this will be discussed a little

later on). Addresses can be reserved for a MAC address or a host name so these clientswill have a fixed IP address that is configured automatically. Most Internet Service

Providers use DHCP to assign new IP addresses to client computers when a customer

connects to the internet - this simplifies things at user level.

The above diagram diplays a simple structure consisting of a DHCP server and a number

of client computers on a network.

The DHCP Server itself contains an IP Address Database which holds all the IP addresses

available for distribution. If the client (a member of the network with a Windows 2000Professional/XP operating system, for example) has "obtain an IP address automatically"

enabled in TCP/IP settings, then it is able to receive an IP address from the DHCP server.

Setting up a DHCP Server

This will serve as a step-by-step guide on how to setup a DHCP server.

Installing the DHCP server is made quite easy in Windows 2003. By using the "Manage

your server" wizard, you are able to enter the details you require and have the wizard set

the basics for you. Open to "Manage your server" wizard, select the DHCP server option

for the list of server roles and press Next.You will be asked to enter the name and description of your scope.

Scope: A scope is a collection of IP addresses for computers on a subnet that use DHCP.


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The next window will ask you to define the range of addresses that the scope will

distribute across the network and the subnet mask for the IP address. Enter theappropriate details and click next.


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You are shown a window in which you must add any exclusions to the range of IP

addresses you specified in the previous window. If for example, the IP address 10.0.0.150

is that of the company router then you won't want the DHCP server to be able todistribute that address as well. In this example I have excluded a range of IP addresses,

10.0.0.100 to 10.0.0.110, and a single address, 10.0.0.150. In this case, eleven IP's will be

reserved and not distributed amongst the network clients.

It is now time to set the lease duration for how long a client can use an IP address

assigned to it from this scope. It is recommended to add longer leases for a fixed network(in the office for example) and shorter leases for remote connections or laptop computers.

In this example I have set a lease duration of twelve hours since the network clients

would be a fixed desktop computer in a local office and the usual working time is eighthours.


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You are given a choice of whether or not you wish to configure the DHCP options for thescope now or later. If you choose Yes then the upcoming screenshots will be of use to

you. Choosing No will allow you to configure these options at a later stage.


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The router, or gateway, IP address may be entered in next. The client computers will then

know which router to use.

In the following window, the DNS and domain name settings can be entered. The DNS

server IP address will be distributed by the DHCP server and given to the client.


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If you have WINS setup then here is where to enter the IP Address of the WINS server.You can just input the server name into the appropriate box and press "Resolve" to allow

it to find the IP address itself.


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The last step is to activate the scope - just press next when you see the window below.

The DHCP server will not work unless you do this.

The DHCP server has now been installed with the basic settings in place. The next stage

is to configure it to the needs of your network structure.

Configuring a DHCP server

Hereunder is a simple explanation of how to configure a DHCP server.

The address pool displays a list of IP ranges assigned for distribution and IP address

exclusions. You are able to add an exclusion by right clicking the address pool text on the

left hand side of the mmc window and selecting "new exclusion range". This will bringup a window (as seen below) which will allow you to enter an address range to be added.

Entering only the start IP will add a single IP address.


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DHCP servers permit you to reserve an IP address for a client. This means that thespecific network client will have the same IP for as long as you wanted it to. To do this

you will have to know the physical address (MAC) of each network card. Enter the

reservation name, desired IP address, MAC address and description - choose whether you

want to support DHCP or BOOTP and press add. The new reservation will be added tothe list. As an example, I have reserved an IP address (10.0.0.115) for a client computer

called Andrew.


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If you right click scope options and press "configure options" you will be taken to a

window in which you can configure more servers and their parameters. These settingswill be distributed by the DHCP server along with the IP address. Server options act as a

default for all the scopes in the DHCP server. However, scope options take preference

over server options.

In my opinion, the DHCP server in Windows 2003 is excellent! It has been improvedfrom the Windows 2000 version and is classified as essential for large networks. Imagine

having to configure each and every client manually - it would take up a lot of time and

require far more troubleshooting if a problem was to arise. Before touching any settingsrelated to DHCP, it is best to make a plan of your network and think about the range of

IPs to use for the computers.


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Documents

After Installing the DHCP