To configure a station's primary interface to recognize a subnetted Class B address that is using 8 bits of the host ID for defining the subnets, create or modify the /etc/config/ifconfig-1.options file and insert the following line:
This netmask value indicates that for the primary interface, the upper 24 bits of the Internet address represent the network portion of the address, and the remaining 8 bits represent the host ID. The nonsubnetted netmask for a Class B address (in hexadecimal) would be 0xffff0000. The netmask value can be set using hexadecimal, dot-notation Internet address, or pseudo-network name formats. This entry must be made on all stations on the subnet.netmask 0xffffff00
Note: For stations with multiple interfaces, the network mask should be set for each interface in the appropriate ifconfig-*.options file.