  We study the linearization of the Dirichlet-to-Neumann map for
Poincar\'e-Einstein metrics in even dimensions on an arbitrary compact manifold
with boundary. By fixing a suitable gauge, we make the linearized Einstein
equation elliptic. In this gauge the linearization of the Dirichlet-to-Neumann
map appears as the scattering matrix for an elliptic operator of 0-type,
modified by some differential operators. We study the scattering matrix by
using the 0-calculus and generalize a result of Graham for the case of the
standard hyperbolic metric on a ball.
