You want to manually delete the CTL file from a single Cisco 7961 IP phone.
Which of the following should you do?
A.
Delete the file from the TFTP server and restart the IP phone.
B.
Press Settings > **# > Security Configuration > CTL File on the IP phone.
C.
Press Settings > **#** on the IP phone.
D.
Delete the file from the UCM server.
Explanation:
To manually delete the Certificate Trust List (CTL) file from a single Cisco 7961 IP phone, you should press
Settings > **# > Security Configuration > CTL File on the IP phone and then erase the file. You can access the
Settings menu by pressing the settings button on the phone’s keypad. The **# keypad sequence unlocks the IP
phone’s settings so that they can be modified. CTL files are a component of a secure Cisco Unified
Communications Manager (UCM) configuration. They are used as part of the device, file, and signaling
authentication process. When a phone initializes, it downloads the CTL file from the Trivial File Transfer
Protocol (TFTP) server.
You might need to delete a CTL file from an IP phone if you move the phone to a different UCM cluster or to
storage. You might also need to delete a CTL file from an IP phone if the secure cluster’s configuration
changes or you lose the security tokens with which the CTL was signed.
You should not delete the file from the TFTP server. Deleting the file from the TFTP server would remove the
file’s availability to all IP phones registered with the secure server, not just the IP phone you are servicing.
You should not press Settings > **#** on the IP phone. The phone will reset when you press the **#** keypad
sequence at the Settings menu of a Cisco IP phone. An IP phone reset will reinitialize the phone, which means
that the phone will reboot, contact the Dynamic Host Configuration Protocol (DHCP) server to obtain network
configuration information, and then download its configuration file from the TFTP server. The IP phone will also
unregister and reregister with the Cisco call processor platform.Reference:
Cisco: Cisco Unified Communications Manager Security Guide, Release 8.5(1): Deleting a CTL File Entry