We're trying to configure multiple 7931's using SIP Firmware with an external provider.
We're hitting a few issues: (Note: the port and SIP information is gleaned out of WireShark).
We've tried various methods to get these to connect properly, these are outlined below!
1: The phone sends SIP Register requests from a High Port (eg:43125) to 5060, the provider responds with "SIP Status 100 trying" to the same high port which the phone requested on, and drops or ignores the request. We then get a "SIP Status 401 Unorhorised" (This is with NAT switched ON through our provider), either with or without a ALG (Application Layer Gateway) that supports SIP.
2: If we switch NAT off on our provider, combined with a ALG that supports SIP, registrations succeeds and we can make outbound calls. Inbound however, fails.
3: If we switch NAT off on our provider for the line, without an ALG that supports SIP no registrations occurs and no calls can be made.
Does anyone know if there any way to force the phone to send requests on 5060? (just like the Cisco 7940 does)or, have the phone accept responses on the same port on which it sent the Register request?