Brother DCP-9040CN Service Manual page 442

[ 3 ] Restoring the network settings
The procedure below allows you to return the LAN settings to the factory setting values.
<Operating Procedure>
(1) Press the Menu button. Next press the or button to select "LAN". Press the
OK button
(2) Press the or button to select "Factory Reset". Press the OK button
(3) Press the 1 button select "Reset".
(4) Press the 1 button select "Yes".
App. 2-2 Confidential