Configuring DHCP to work with Cisco 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) buy clicking on “Start” then “Setting” then “Control Panel”. After the Control Panel open click on the “Administrative Tools” icon, and then the “DHCP” icon.

2) After the DHCP management console opens click on “Action” then select “New Scope…” then “OK” to the “New Scope Wizard”, 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 a end IP address, then use the up and down arrow buttons to increases or decrees the length of your sub-net mask, (just keep clicking the arrow buttons till you see the sub-net mask you what to use) and 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 be 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 how long you want the lease to be good for; 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 it’s new IP address, I select “Yes” and enter the “Router (Default Gateway) IP address, and click “Add” and then click “Next”.

7) Next you can enter and any Domain information you have and then click “Add” then “Next”.

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

9) In the right hand plane of the DHCP management console windows double click on “Scope Options”, the 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, and click OK. Now when a client asked for a new IP address it will also get the TFTP server’s address, which the Cisco IP phones need to boot.