A customer is having troubles to get a good integration between Icon endpoints and Aastra PABX.
The icon get's registration from Astra, and it can dial VoIP calls to other phones, but when a phone dials to the Icon it never receives the request, the call is dropped by timeout.
This is not all, after among 5 to 10 seconds, the Icon receives the call request, it starts ringing and shows the ID of the caller, but when it picks up there is no active call.
The firewall has opened 5060, 5061 and 17000 to 31999 range , TCP and UDP in both directions.
Any ideas about what's going on?
Here are the details:
Icon 400 Version LS_RM3_2.10.0 (1981)
Mitel Aastra MX-ONE Version TSE 188.8.131.52.3 SP2