I am doing an initial install behind a firewall I do not control. I haven't setup a new box in a while, other than not being able to update the FW, what other issues will I encounter not being able to see the internet?
You won't be able to register it which is necessary if you want cloud based dashboard. (control from outside your lan) Other than that things will be fine locally. Though you definitely want to be on the latest platform and latest z-wave firmware which you need internet for.