MIDIRMX

If your DAW does not recognise one of your MIDI controllers so you need to route it to a standard port, or you want to split your controller keyboard into two different channels and transpose each half differently before the DAW (eg to include key switches), or you want to play a bunch of MIDI loops and pause for 5 seconds between to automatically save them to separate MIDI files, or you want to monitor MIDI before the DAW -- this is a useful 99-cent download from the Apple App Store.

Settings are automatically saved, so in Login Items you can set it to launch at login.

Easy-peasy.