Hello,
I had a phone in remote branch connecting to CUCM through IPSec tunnel, The phone couldn't complete registration process
I checked communication between CUICM and phone and traffic is moving between both sides without any issue
I traced logs in RTTM and the phone appears to be registering then unregistering in milliseconds.
I inspect that connection is terminated from either sides but or some Firewall/IPS in between. But the weird thing that I tested the same phone with same edge router and internet connection in other site and worked perfectly.
Phone model: Cisco IP Phone 7841
Phone version: sip78xx.11-0-1-11.loads
CUCM:
Procuct Version: 11.0.1.20000-2 Unrestricted
Unified OS Version: 6.0.0.0-2.i386
