Patrick, Thanks for you comments but they regard normal migration processes, my question was purely regarding VPN phones and the use of blank ITL/CTL. From memory updating ITL/CTL for VPN phones is blocked to mitigate man in the middle attacks but c...

Patrick, We have a pair of servers running CuCM. Craig

Patrick, My situation is slightly different, the need to change the CUCM platforms domain which will regenerate the ITL and CTL. Phones are using username and password. Many Thanks, Craig

Luke, How did you manage the migration in the end? I am looking at updating a customers domain name and wanted to use the roll back option but am unsure if this will work for the VPN phones. If any body can guide some advice and guidance that woul...

Islam,     I think your issue would be resolved by setting 'Channel IE Type' on the E1 port in CuCM to 'Continuous' and reset the gateway if that doesn't work try 'Timeslot'Have a look at great the interoperatbilty guide at:-http://www.cisco.com/en/U...