Configuring Reaper for yMIDI Control Surface

If you have not configured an rtpMIDI session for the control surface see this page for instructions

In Reaper go to Options | Preferences | Audio | Midi Devices and make sure the rtpMIDI port for MIDI control is enabled for input and output. Do not enable the rtpMIDI port that was configured for yMIDI's control surface

In Reaper if you enable a MIDI device it will not be available for use with a control surface.

Next go to Options | Control Surfaces. Click the Add New button to add a new control surface definition. Select Mackie Control Universal as the control surface type. Select the rtpMIDI network MIDI device that was setup for the control surface as the in and out MIDI ports.