Configuring DHCP to work with Cisco Manager

Posted November 3, 2006 by kel in Cisco call manager

This Tech-Recipe describes using an external DHCP server, in this case from a Windows Server 2000 or 2003 system, with Cisco Call Manager (CCM). When introducing CCM into environments with an exsiting DHCP infrastructure, problems may occur because Cisco IP phones require additional information from the DHCP server when they startup. Following the steps in this Tech-Recipe will allow the use of a non-CCM DHCP server.

This Tech-Recipe assumes the Cisco Call Manager (CCM) is already installed and running properly. Instead, we will deal with setting up the DHCP server on the CCM hardware.

1) Start the DHCP server software that is already installed on your server (It comes with Server 2000 or Server 2003.) by clicking on Start, then Setting, and Control Panel. After the Control Panel opens, click on the Administrative Tools icon and then the DHCP icon.

2) After the DHCP management console opens, click on Action and then select New Scope…. Click OK for the New Scope Wizard, and then type in the name of your scope. This can be almost anything you would like. I named mine voip_scope. You can also give it a description if you like. I did not.

3) Then click Next, and enter a start IP address and an end IP address. Then use the up and down arrow buttons to increase or decrease the length of your sub-net mask. (Just keep clicking the arrow buttons until you see the sub-net mask you what to use.) Then click Next.

4) Next, you will be asked to enter any address you do not want issue out be the DHCP server. Maybe you are saving some static addresses for you router and/or servers. You can enter in just one address by entering the same address in the start and end boxes or a range of addresses by putting the first or lowest in the start box and the last or highest in the end box. Then click Next.

5) You will be asked for how long you want the lease to be good. I leave it to the default and click Next.

6) Next you are asked if you want to set up the DHCP options now. These are the options the DHCP server will pass along to the requesting client with its new IP address. I select Yes and enter the router (Default Gateway) IP address. Then click Add and Next.

7) Now, you can enter any Domain information you have, and click Add and then Next.

8) You can now add and WINS information you have. I leave mind blank, and click Next. The last question you are asked is if you want to activate the scope now. I select Yes and Next and then Finish to close the New Scope Wizard.

9) In the right hand pane of the DHCP management console windows, double-click on Scope Options. Click Action and select Configure Options…. Then in the Scope Options box, click 066 Boot Server Host Name to check that option, and in the String value box, enter the IP address of your TFTP server. Mine happens to be the same as my CCM. Click OK. Now, when a client asks for a new IP address, it will also get the TFTP server’s address, which the Cisco IP phones need to boot.

The Conversation

Follow the reactions below and share your own thoughts.