  When a (frequency-domain) boundary value problem involving a homogeneous
linear material is solved to assess the validity of the Post constraint, a
conflict arises between the fundamental differential equations of
electromagnetism in the chosen material and a naive application of the usual
boundary conditions. It is shown here that the conflict vanishes when the
boundary conditions are properly derived from the fundamental equations, and
the validity of the Post constraint in modern macroscopic electromagnetism is
thereby reaffirmed.
