Reolink products support both LAN and WAN connections. Check below for more information about these 2 kinds of connections.
Applies to: All Reolink cameras and NVRs
LAN
It means local area network. For example, in your home, all the devices are connected to the same router. The network under your router is a LAN.
If your devices (phone/PC) and the camera are on the same LAN, then you don't need the Internet to connect to the camera/NVR.
For a more detailed definition of LAN, please check Local area network.
WAN
It means a wide area network. For example, in your home, the network under your router is a LAN, and the network outside your router (your ISP's network) is a WAN. Compared to LAN, WAN is a much larger network. And the Internet is the largest WAN.
And if you want to connect to the camera/NVR in a WAN, it requires that your camera/NVR (LAN) is connected to the Internet.
For a more detailed definition of WAN, please check Wide area network