How to - Removing CTL and ITL from 7900-series phones via SSH
Which Cisco UC engineer does not know the challenge when he runs a CUCM in mixed mode: How to remove a Certificate Trust List on a phone nobody has physical access to during a CUCM migration? The normal way like using the same security tokens on old and new CUCM is not possible. Sending somebody on site during the migration is also not possible. These limitations raised the need for an alternate solution. After some testing, I decided to create a small Python script. The final script connects via SSH to the phone and uses the test key functions of the Cisco SIP phone debug-mode to press the required phone buttons via command line interface. Main requirement is to enable SSH for phone on the CUCM and to configure a username and password for the SSH access. The following script is based on Python 3.4 and uses as additionally Paramiko for the possibility to connect via SSH to the Cisco IP phones. Besides Paramiko also the time class is required to implement some d