Can I connect my PC to a NAS directly while connected to the internet
Yes. This way a NAS have no Internet access. Only access you get is directly or via seperate switch.
Step 1 - set a manual IP on a NAS (similar range to your PC IP)
Step 2 - set a manual IP on a PC
Step 3 - Connect a LAN cable between a NAS and a PC (or via switch)
![](https://i.ytimg.com/vi/3lro0Zv4VNs/maxresdefault.jpg)