SubnetMask

255.255.255.0 subnet for a node
A node must give out a subnet address of 255.255.255.0 Change the setting on the firewalling menu same node clients firewalled to yes, It will restore the 255.255.255.0 subnet for that node.

ifconfig eth1 netmask 255.255.255.0 Is the manual way to do it

And a Defaultgateway must be added. See GatewayNotes.

route add default gw 192.168.169.1