Jonathan Schulenberg Mon, 06/15/2009 - 10:27
User Badges:
  • Super Bronze, 10000 points or more
  • Cisco Designated VIP,

    2017 IP Telephony

It stands for Certificate Trust List and is only available if you have your UCM cluster in Mixed Mode. If you are not using authentication or encryption, you will not have a CTL.

parshah Tue, 06/16/2009 - 10:48
User Badges:
  • Cisco Employee,


As per the most from j.schulenberg, 'CTL update failed' means the phone could not get the CTL file.

Now, let me ask you this, is you CUCM cluster in secure/mixed mode?

You can verify that by going to Enterprise Paramters page and look for 'Cluster Security Mode' if its anything but 0 than your cluster is in secure(2) or mixed(1) mode.

Now, do you want your cluster to be in secure/mixed mode or not? If not, that you need to change the cluster security mode to unsecure(0) using the CTL client. If you want it to be in secure mode, you need to make sure that the TFTP server that the above mentioned phone connects to is in the list of servers in the CTL client.


Asad yaseen Tue, 01/17/2012 - 12:51
User Badges:

if the phone is not updating the trust list then you have to erase it manually beacuse some time even after factory default reset it doesnt work.

Reseting the IP Phone CTL manually#

press settings ==> then **# to unlock the settings => then go to security configuration => Trust list => select the CTL file and press erase

The phone will reset and wait for downloading the new CTl files from the tftp server.

Reference Link #

Troubleshooting Cisco IP Phone Registration Problems with Cisco CallManager


This Discussion