I investigated a bit, and this should be a net_server bug, not a bug of the Network preflet. With the exact same settings file: on boot, net_server fails to add the gateway route in manual settings mode. When the Network preflet is used to (re)write the exact same settings file, the gateway is added propery. At first I thought it might be a problem in which order the settins are applied (the gateway is considered as pretty much the first thing), I thought it might need the other settings to be originally applied to work, but moving the gateway stuff down as the last thing in NetServer.cpp didn't help.
