sundance-communications.com/forum Forums TDM Business Telephone Systems Vodavi Telephones & Systems SBX 320 One to One router workaround

I am wondering if anyone has been able to de-mystify why the SBX 320 needs an extra IP address from the internet service provider.

I have spent a while trying to figure out why I can't use it behind a NAT router.

I have a listing of all the ports used and have played around trying to make the VOIB card work behind a NAT router with no luck.

The IP phone attributes page shows the phones external IP address and that it's a remote set but no luck with the phone connecting. It just keeps saying no ACK.

It seems the phone does a multicast request to 239.20.19.50 using IGMP, but the document I have says it uses port 6254. My understanding of IGMP is it's a layer 3 function and has no specific ports. Is there any IP gods out there that can shed some light on this?

Thanks

Assuming that you're trying to connect over the internet, I don't believe the multicast request should not play into your equation. That would only be useful for a system on your local network.

I've never tried to connect an SBX IP phone behind a router without a dedicated IP. I have done it with the Telenium/iPECS system, which is like the SBX's bigger, smarter brother.

I did this by forwarding UDP ports 501-9900 to the KSU. However, the iPECS has an entry for "firewall address" which I do not believe the SBX does. The outside VoIP connection will not work without this setting, so it probably won't work on the SBX. May be worth a try.

I nver connect XTS's behind NAT. I always use a static dedicated IP. With the phones, DHCP behind NAT works except I did run into a problem with a VPN arrangement. I ended up with one way transmission, audio out of the VPN but not coming back. So I installed a router with its own IP and switch in front of the firewall and ran the IP phones on the new router. Problem solved.