Verizon USB modem with Polycom IP7000

[sakilgar]

I recently purchased a Pantech UML295, a Cradlepoint MBR1400v2 router, and a Polycom IP7000. I have a SIP server that I am attempting to connect to, but the process fails when I connect to the internet via the USB modem. I can use a hard-wired connection and WiFi as WAN on my AT&T mobile phone on the Cradlepoint, and the Polycom connects with ease.

I called Verizon support, and they said that they were not blocking any ports, and they could not offer much help past that. It looks like my USB connection is double NATed as my WAN is 70.x.x.x, but the USB IP is 100.x.x.x, and then my internal IP is 192.x.x.x. Internet traffic seems to functional from a laptop over the USB-Router-Internet, but there is an issue with the SIP phone not registering.

Any help would be greatly appreciated.

[luriep]

It would be interesting to see if the packets actually make it to the SIP server, and what's in them. 

Is there any way you could pull logs on the SIP server (or run wireshark on the SIP server) and see if anything's actually getting there from the IP7000?  (I assume yes) and what's inside the SIP packets will hold all the answers. 

[sakilgar]

The SIP server did not show any attempted registrations. I do not have the access to install a packet sniffer on the server as I only have a remote connection.

However, I tested an AT&T modem connected to the Cradlepoint router and the Polycom immediately registered and is completely functional. The verizon modem is heading back to the store.