We consider the 3d Vlasov-Poisson system in an infinite, convex domain (think of generalizations of a half-space), with perfectly conducting wall (Dirichlet for the electrostatic field; particles are absorbed when they touch the boundary). Solutions are global, and we describe their asymptotic behavior based on a correction defined on the asymptotic cone. This is a joint work with W. Huang and M. Suzuki.