Pavel Stefanov’s Blog

John O’Callaghan feat. Audrey Gallagher – Big Sky (Markus Schulz a/X Remix)

I’ve had difficulties with some task in the Internetwork Expert and IPExpert workbooks asking to configure the router to supply the address of a CallManager server to hosts so I decided to show you where you can find the numbers of the DHCP options in case you forget them during your lab.

Supplying the CallManager address can be done via two DHCP options, that is option 66 and option 150. Both options actually specify a TFTP server address (option 66 can also specify a FQDN (fully-qualified domain name), but the IP Phone would need a DNS server to resolve the name to an IP address). Cisco recommends using option 150 because option 66 might be used for some other purposes in your network.

Now, to get back to the purpose of this post – locating those two options on the Documentation CD:

1. Go to www.cisco.com
2. The Support drop-down menu and then under Maintain and Operate
3. Voice and Unified Communications -> Call Control -> Cisco Unified Communications Manager (CallManager) -> Maintain and Operate Guides
4. Choose one of the Administration Guides and under DHCP Server Configuration you should be able to locate the numbers of the DHCP options (Note: If you choose a 6.x or later Administration Guide, the DHCP Server Configuration is located under System Configuration)

HRs must be the smartest people on Earth having developed so many new technologies or introduced new terms in networking :) Don’t you just love it when they put some words together they’ve googled or got from the first networking forum?

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