Networking
DHCP

Dynamic Host Configuration Protocol is used to assign IP addresses to host computers. To do this, a DHCP server must be installed and configured.

The DHCP must have one NIC with a static IP address. That address must be within the range of IP addresses that will be assigned to host computers.

The above IPCONFIG information is for a computer with two network cards. One card (Local Area Connection) has an IP address of 192.168.2.1 and a subnet mask of 255.255.255.0. This is the NIC that will used for the DHCP server.

Before setting up the DHCP server, the range of IP addresses that will be assigned must be determined. There may be devices already using these IP addresses. Some of these devices may need to keep the IP address currently being used. For this DHCP server, the numbers from 100 to 250 in the current subnet will be assigned. No computers in that range are currently being used.

Begin by going to the Control Panel and installing the DHCP service.

Click Start/Control Panel

Double-click Add/Remove Programs.

The DHCP service is included as a component of Windows 2000. To install this component, clic the Add/Remove Windows Components button on the left of the screen.

The DHCP service is one of the Networking Services. Double-click the Networking Services listing to show all the components of that service.

Check the box in front of t Dynamic Host Configuration Protocol (DHCP).

Click OK.

This will install the DHCP service. You must now activate that service and create a scope. To setup a scope, start the DHCP administration tool.

Click Start/Programs/Admistration Tools/DHCP

The DHCP service is installed, but there are currently no active scopes. A scope is all the settings that make up a particular DHCP set. A scope includes the range of IP addresses to be assigned, subnet mask, default gateway, any IP numbers in the range that will be excluded, the DNS and WINS addresses and the lease duration.

Right-click the server and select New Scope.

This will be begin the New Scope Wizard. Click Next.

Give the scope a name. This name is only used in the DHCP control panel. Use a name and description that will help you remember the computers this DHCP server is serving. Client computers will not even know these names. Click Next.

Enter the range of addresses that will be assigned by the DHCP server. Enter the first and last IP number (inclusive) that will be in the pool of available IP numbers. Don't worry about devices with current IP addresses in the pool. You will have a chance to exclude those addresses before activating the scope.

Enter the subnet mask by either designating the length or by typing the subnet mask in. The subnet mask entered here must match the subnet mask on the DHCP server NIC.

Click Next.

Now enter any IP addresses in the current range that you do not want to be published with DHCP. This is useful if you have critical equipment (e.q. Network Printer) that already has a static IP address in the DHCP range. You can tell the DHCP server to skip that number when assigning IP addresses.

Click Next.

Next the lease duration must be configured. The lease duration is the amount of time a host NIC will use the assigned IP address before the server takes it back, and puts it back in the "available" pool of IP numbers. The client will ask that the lease be renewed at the point when the lease is half over. It is a good idea to have the lease be long enough that a server problem (say the DHCP server crashes) not cause network problems. If the lease is the default eight days, a DHCP server can be down for a whole weekend, and the client will only make it to the halfway point of the lease.

Avoid creating lease times that are extremely long (like a whole semester). If you do this, visitors to your district that bring their own labtops will take leases for the whole term when they leave the building.

Click Next.

At this point, you can activate the scope or continue with the scope options. Usually you will want to assign a default gateway and DNS with the IP address, so it's generally a good idea to configure those things now.

Select YES and click Next.

Add the address of your network router. This is your Default Gateway.

Click Next.

Add the IP addresses of your DNS server. If you have multiple DNS servers, put them all in. Make sure the top-to-bottom order is correct.

Click Next.

If you are using a WINS server, add that IP address in the WINS Servers dialog box.

Click Next.

If you are ready to active this scope (enable it), select YES and click Next.

Your scope is now ready for use. Computers on your network can begin to request IP addresses from the pool.

Reservations

In a school, you will probably want to know which computers have what IP addresses all the time. Ideally, you want every computer to have the same IP address all the time. There is a way to "reserve" an IP address for a specific computer.

Under the scope, right-click Reservations.

Enter the IP address and the MAC address of the computer that will use this reservation. If you don't know the MAC address, run

IPCONFIG /all

from the command line on the host computer.

Click Add.

Now this computer will always get the same IP address from the DHCP server.