just trying to stay focussed on underlying problem: netmask is not the problem, else ping, ftp, etc, would not work.
frc documentation states clearly that 255.0.0.0 is correct (ref:
http://www.usfirst.org/uploadedFiles...adio_Rev_A.pdf,
http://www.usfirst.org/sites/default...20System_2.pdf)
in any case, either netmask 255.0.0.0 or 255.255.255.0 will work for 2 clients, 10.xx.yy.2 a nd 10.xx.yy.6.