Temporal direct numerical simulations (TDNS) were carried out for a Mach 6.0 boundary layer on a 2-D porous wall. The porous wall was implemented with an immersed boundary scheme. For validation purposes results were compared with results obtained with an analytical porous wall model. A grid convergence study was conducted to confirm that the grid resolution was adequate. A parameter study revealed that the geometric dimensions for which the porous coating most effectively attenuates the growth of disturbances in the boundary layers. For the optimal parameter setting significant stabilization of the temporal growth of the instability waves is observed. The optimal cavity depth for different numbers of pores per disturbance wavelength was found to remain approximately the same. The present study showed that porous coatings can be modeled with an immersed boundary scheme.