Thank you so much for your prompt replies. You guys scared me now hahaha. I contacted big blue button for their advice.
Do you recommended using other tools even if more expensive ??
Blackboard Collaborate is quite good in my experience and works well in Moodle.
However, check out https://blackboard.secure.force.com/apex/publickbarticleview?id=kA770000000Cbtt - you might not be crazy from a security point of view about the wide range of ports and IP addresses that are required.