

If it’s like a vpn interface, it’s still running as a deamon in the background even if the browsers are closed.
Like others have said you can check what application is using each open port. You can also check running processes (ps | grep keywords) and interfaces (ip a).


My understanding is that hba cards support virtualization better than passing sata directly through. But if you’re not virtualizing the NAS, I wouldn’t see an issue with a reputable motherboard that has enough sata ports at 6 Gbps.
For the cheaper expansion cards I’d see that as a central point of failure and would recommend an hba card over a cheaper alternative.