Quote from: N2VWZ on April 18, 2012, 08:13:49 AM
The SPA2000 works because the EXT IP parameter programmed with the WAN IP address. The OBi100 has no EXT IP parameter for setting the WAN IP.
EXT IP in SPA devices serve very narrow purpose, according to Cisco's administration guide:
If the ITSP network does not provide a Session Border Controller functionality, and if other requirements are met, you can configure NAT mapping to ensure interoperability with the ITSP.
Requirements:
- You must have an external (public) IP address that is static.
- The NAT mechanism used in the router must be symmetric. See "Determining the Router's NAT Mechanism"
- The LAN switch must be configured to enable Spanning Tree Protocol and Port Fast on the ports to which the SPA devices are connected.
Per docs, if you are using EXT IP, you should disable STUN and enable VIA, Which is completely counter-intuitive given that STUN fields are in the middle between VIA and EXT IP.
So, I doubt that EXT IP setting has any effect on your SPA2000. I had it myself, assuming - just like you - that it is needed for direct dialing. Then I figured out how to do it, and then removed EXT IP value (or rather, my dynamic IP changed, so the value was obviously incorrect - so I cleared it) and it continued working.