Concurrent and Unique viewer count (behind corporate network firewall)

We have just run an event with (confirmed) about 2000 viewers. However because majority of these were behind our clients firewall, the concurrent viewers count in the cloud status window only showed about 50 (the approx number of public facing IP addresses).

Would I be correct in assuming that concurrent live viewers is tallied by IP addresses, and not by ie. socket or session connections?

Is there another way, perhaps through the API, that we can find live viewer numbers?

Let me ask and find out for you

I confirmed with our Cloud engineer @Chris Gallop that a CDN will not be able to show you the correct number because of the firewall blocking the public IPs as you already have stated. The only and best way to get the numbers is from the player analytics.