My MRA phone outbound call drops after 3 sec. This happens everytime when Backbone internet is bounce. Cisco TAC recommend only two options to fix the issue. Either restart Expressway as an admin or restart endpoint since they are dealing with two different IP for authentication.
This caused the IP phone to not be able to generate an ACK due to a different IP address received from the first message.
When the network issue happened, something started to reply the messages on behalf of the expressway was introducing it’s address instead of the real expressway address:
It’s really difficult to second-guess TAC with the limited detail offered here. If I were working this issue I would be asking why this is an unrecoverable state that requires a reboot. Presumably the TLS connection is being dropped or reset when the NATed public IPv4 changes? Once that happens why isn’t the phone able to register again as a new connection? Same question if the TLS socket isn’t being cleared: why? From the sidelines it sounds like one side or the other isn’t handling this failure condition very well. Phones shouldn’t be orphaned offline just because an ISP DHCP lease expired; some ISPs even force an address change periodically to discourage hosting a local server without paying extra for a static address.