There is definitely a problem with multiple latter versions of Firmware for the Cambium R series routers.
On versions 4.71-R4 (and several later firmware versions) - after you log into the router’s Network, LAN Page - you can set the local LAN IP address that you want in the router, other than the default 192.168.11.1.
The next column down is the Netmask column.
If you enter 255.255.0.0 in the Netmask field (which is a class B subnet) - the router will NOT provide NAT translation to the WAN address that is programmed in the router.
Unless, the device that is connected to the LAN port on the R series router has an IP address in the same Class C range of the IP address that is programmed in the Local LAN address of the router. - it will NAT translate.
Furthermore, if you load several of the later firmware versions including version 4.81-R4 - the firmware will not even enter any type of Netmask in the field. There is a “0” that is defaulted in the field in those firmware versions.
This is with DHCP disabled in the Local LAN section of the router.
These problem got us into a major bind today!
I spent several hours today loading multiple different versions of firmware in the new R201P router, trying to get one of the version of perform proper NAT translation.
Both of these problems need to be fixed immediately.