WRX rear shocks knocking

Have the car booked in for tomoro to get the rear shocks re greased as there knocking at low speeds on rough ground. Any recommendations??? I know a lot of lads say fit a grease nipple? Is that a good plan? Also is it only the rears? Or do front need to be done too?

Cheers

ya its a great job.. happened both my stis and yes the front can knock as well

white lithium grease is the handy fix , jack the car up , lift the plastic cover up off the shock and spay a bit on, keep her quiet for a few weeks in my experience (8-10 weeks i found )