Applies to: All Reolink cameras and NVRs
LAN means local area network. For example, in your home, all the devices are connected to the same router, and the network under your router is a LAN.
If your devices (phone/PC) and the camera are in the same LAN, then you don't need Internet to connect to the camera/NVR.
And for more detailed definition of LAN, please refer to this link: https://en.wikipedia.org/wiki/Local_area_network
WAN means wide area network. For example, in your home, the network under your router is a LAN, and network outside your router (your ISP's network) is a WAN. Comparing 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.
And for more detailed definition of WAN, please refer to this link: https://en.wikipedia.org/wiki/Wide_area_network