2.4 Creating a DHCP Reservation for a Printer
DHCP client
support is a common feature in network printer devices; it greatly
simplifies the print device installation process. However, the D in DHCP
stands for “Dynamic,” meaning that it is possible for a client’s IP
address assignment to change. If, for example, a network print device is
disconnected or offline long enough for its DHCP lease to expire, the
DHCP server might assign it a different address when you reconnect it to
the network. The print device can communicate with the network, but the
print clients might still have ports that reference the old IP address.
Note
One of the best ways to ensure continued connectivity for a
DHCP-equipped network print device is to create ports using the print
device’s name instead of its IP address. This way, even if the address
changes, the name remains the same.
Another way is to create a reservation for the print device on the DHCP server. A DHCP reservation is an IP address that you permanently assign to a specific client, based on the Media Access Control (MAC)
address encoded into its network interface adapter hardware. The print
device still obtains its IP address from the DHCP server, but the server
always assigns it the same address as long as the print device is
connected to the same IP subnet.
Tip
BEST PRACTICES Although it might be possible to configure your print device manually to use a static IP address, creating
a DHCP reservation is a better solution, so that all your IP address
assignments are documented and managed in one place. If you manually
assign an IP address in your DHCP scope to a device on your network, the
DHCP server might attempt to assign that same address to another device
later. DHCP servers check the network for IP address duplication before
they complete each address assignment, but there is no way to know how
the print device will react to an address conflict.
To create a DHCP reservation for your network print device, use the following procedure:
-
Connect your print device to the network and configure it to obtain its IP address using DHCP.
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Log on to your Windows SBS 2011 server, using an account with network Administrator privileges.
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Click Start, and then click Administrative Tools > DHCP. The DHCP Console appears.
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Expand the node representing your server and browse to the scope that the Connect To The Internet Wizard created on your server.
-
Expand the scope and click the Address pool node.
-
Note the range of addresses available for distribution. Then right-click the Address pool node and, from the context menu, select New exclusion range. The Add Exclusion dialog box appears.
-
In the Start IP address and End IP address text boxes, specify a range of addresses at the end of your scope that is large enough to support all your network print devices. Click Add, and then click Close. The new exclusion range appears in the Address pool list.
-
Click the Address leases node.
-
Locate the lease for your print device in the list and adjust the column widths in the console so that you can see the entire Unique ID value for the lease.
Note
Your print device most likely has a host name that you do not
recognize, one that is different from the names you have assigned to
your network computers.
-
Click the Reservations node, which displays an empty list, and then click the Address leases node again.
-
Right-click the Reservations node and, from the context menu, select New reservation. The New Reservation dialog box appears.
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In the Reservation name text box, type the name of your network print device.
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In the IP address text box, type one of the IP addresses in the exclusion range you just created.
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In the MAC address text box, type the Unique ID value for your print device’s current address lease.
Note
The Unique ID value is the hardware address assigned to the print device’s network interface adapter by the manufacturer.
-
Click Add, and then click Close. The reservation appears in the Address leases list, with a Lease expiration value of Reservation (inactive).
-
Turn the print device off or unplug it from its power source. Wait 30
seconds; then turn the print device back on or plug it back in. Wait
another 30 seconds for the print device to initialize.
-
In the DHCP Console, on the Action menu, click Refresh. The print device’s original address lease disappears from the Address leases list, and the reservation you created now has a Lease expiration value of Reservation (active).
-
Close the DHCP Console.
From now on, each time the DHCP server receives an IP address request
from the print device containing the MAC address you specified, the
server assigns the address in the reservation you created.
