I want to know about the TFTP server. Cisco IP Phone 7940/7960 installed in our LAN network. And we have edge router Cisco 3845.
We are using Asterisk on Cloud. The phone get registered via that Asterisk installed on cloud. But mostly the phone firmware got corrupted. And they show "Application Protocol Invalid". I did not define any TFTP server in Router DHCP Configuration. Cisco Router 3845 is acting as DHCP server.
0.0.0.0 is TFTP server in phone setting.
The phones also stucked on configuring IP then I have to release and renew the IP address from phone setting menu button.