ANOVA, residual normality assumptions

#1
Hi everybody,
I would like to ask you something about the normality hypotesis on the residuals when performing an ANOVA. Do I have to check the entire residuals data set or, do I have to check normality of the residuals relative to each level of each IV (for example, 1 IV with 3 levels, 3 normality tests)?
Thank you.
Regards.

Nelson