  Using covariant quantization of the electromagnetic field, the Casimir force
per unit area experienced by a long conducting cylindrical shell, under both
Dirichlet and Neumann boundary conditions, is calculated. The renormalization
procedure is based on the plasma cut-off frequency for real conductors. The
real case of a gold (silver) cylindrical shell is considered and the
corresponding electromagnetic Casimir pressure is computed. It is discussed
that the Dirichlet and Neumann problems should be considered separately without
adding their corresponding results.
