are there any network devices before reaching nethserver? (modem, router, firewall…)
Internet connection type (xDSL, fiber…)?
Is nethserver connected to a modem, or configured as PPPoE with settings given by the provider, or something else?
From some screenshot I think it is connected to a modem and receive a public IP address, but I could be wrong.
Maybe with the network map and settings someone else will get a better picture and can help.
On ClearOS, how were the network interfaces configured?
A few of the underlying status checks for the UI are described in this topic (Firewall Issues, not recognizing my pppoe as a provider). Might not be the same case… Only don’t know how far we can get to figure it out.