Adobe hosted videophone example doesn't work?

Question

What can be going wrong for me when others claim this is working??
I've tried using the Adobe hosted videophone example at http://labs.adobe.com/technologies/cirrus/samples/
It works fine for me when I have two machines on the same LAN both connecting to the service with firewalls operating.
It does NOT work when one of the machines has a different connection to the Internet, hence diff IP address
I checked that UDP outbound and inbound is permitted in each firewall.
Even when I turn firewalls OFF on both machines the app only works when both machines are on the same LAN.
We have tried this from net connections in USA and UK: in both locations, the videophone app works fine between machines on the same LAN, but fails to work when machines are on a separate Internet connection; and, it goes without saying, we can't connect the videophone app internationally.
Now all of this is with the Adobe hosted example. We downloaded the sample code and followed the instructions in this article and set up our own working examples, both in a web-hosted Flex version and a desktop AIR version. Again, similar results: our own web and AIR versions work just fine when talking locally over a LAN, but both fail when two machines are connected to different Internet connections and this is regardless of Firewall settings.
This is REALLY frustrating and we wonder what we can be missing?!

Answer 1

Thanks for the helpful pointers, Michael. It seems that we likely are running into NAT or firewall issues.
However, that leaves me wondering what on earth Cirrus can be useful for in the real world? I guess it is just possible that it might be useful in a large corporate campus where you can run multiple instances of an app on machines behind the same firewall; but for anything that is designed to be deployed on multiple end-user machines across the Internet it has no usefulness that I can see. In the real world, there is a huge mix of router and firewall configurations that the developer can have no control over: the P2P capabilities need to handle this without requiring end users to do nasty config work.
Adobe seems to have dropped the ball here: on the one hand, AIR apps can be easily installed and updated with a single button click; but if the new P2P capabilities are to work it seems we have to get end users to do nasty editing of configuration files to tunnel through NAT/firewall.
This is just not a subject that most Flex and AIR developers will have experience of so we really need some easy step-by-step instructions or better tools to enable us to make use of these capabilities in the real world!