By default, a CUCM server refers to key servers, including itself, by name rather than by IP address. This works, but makes your phone system vulnerable to DNS outages. Best practice is to reconfigure CUCM with explicit IP addresses so that your phone system will continue to operate even when the phones are unable to reach their DNS servers.
Tasks
Change the hostname for your CUCM server to an explicit IP address in its Server Configuration page
In each of the URLs that your CUCM server supplies to phones, change the server's name to an explicit IP address
Starting Point
You should already have a working CUCM install within a virtual machine with a supporting network and services, as described in lab A-1. This is the same setup you used in Lab 8-1. If CUCM and your web browser aren't already running, start them. Detailed instructions are contained in the first several steps of 8-1.
Table 1. Important Addresses and Logins
CUCM Address
CUCM Admin Login / Password
CUCM OS Admin Login / Password
10.0.4.5
student / ciscoclass (Used for almost everything)
cucmroot / ciscoclass (Used for the OS Admin interface and the console login)
Comprehension
What menu sequence takes you to the screen where you can change how the CUCM server refers to itself, from a name to an IP Address?
What menu sequence takes you to the screen where you can change how the CUCM server tells phones to refer to it, from a name to an IP address?
Exam Objectives
This is never explicitly mentioned in Cisco's exam objectives, but understanding the inherent weakness introduced by CUCM's default dependence on DNS may help you diagnose end user problems, as requested in the exam objectives in the table below.
Table 2. Exam Objectives
5
Provide End User Support
5.2
Define fault domains using information gathered from end user
5.3
Troubleshoot endpoint issues
Lab Walkthrough (Screenshots are clickable)
In your web browser, navigate to the Cisco Unifired CM Administration page (https://10.0.4.5/ccmadmin) and log in (student/ciscoclass). Under the "System" menu, choose "Server." If the list of servers is empty, hit the [find] button to show the complete list of servers (you only have one).
(Admin) System → Server [find]
Choose Your Server
In the list of CUCM servers, click on the hyperlink to your server (cucmlab).
Change the Server Name to an IP Address
Replace your server's name "cucmlab," with its IP adress, 10.0.4.5, in the "Host Name / IP Address" field, near the top of the screen. Click [Save], either by scrolling to the botom of the page or using the icon near the top, directly beneath the page title, at the bottom of the non-scrolling portion of the window.
Use IP Addresses for the URLs Given to Phones
Navigate to:
(Admin) System → Enterprise Parameters
If you don't see "Enterprise Parameters" under the system menu, make sure your browser window is tall enough to show the whole menu. After scrolling about halfway down the page, you'll see two sections, entitled "Phone URL Parameters" and "Secured Phone URL Parameters." Change the four URLs in each section (total of 8) to use the server's IP address instead of its name.
