I have an issue with a few Cisco IP Phones (7940) model. it says registration rejected. and when I brought them to the HQ, it registered directly without any issue.
but the strange this is that, when I connect a 7942 or newer models to the same port of the 7940 s, they will register. I also disabled all the firewall rules on the MikroTik of the other offices, but still the same. I allowed everything on the data center firewall between these two subnets. still rejects the registration.
I have also removed the phone from the CUCM and then added it back. still the same. I changed the firmware to SIP and then reverted back to SCCP. still the same.
I have seen that the Phone DN is empty when I want to check the DN through the IP address of the phone in the Device Information. I have attached a snapshot of it.
The CUCM version is 11.5.
The Boot Load ID of the phones are : PC0303010001
The App Load ID of the phones are : P0030801SR02
I searched for newer firmware. but was not able to find one.
Any suggestion is appreciated.
For anyone that might come across this topic and face the same issue. I did anything that came to my mind and almost anything I found online, but none of them worked. later I found out that the 7940s were using the CUCM TFTP server as a call manager which they shouldn't use it since these servers meant to be used only for downloading firmware and configuration files, and only the 7940s were using it as Call Manager. not the 7942s nor the newer models.
Hi, it’s been one year since the last post on this thread. Just wanted to check if you got resolution for this. We are having exactly same issue... phone is trying to register with tftp... our cucm version is 11.5