We have theoretically investigated the role of the interfacial arrangement on the transport properties of finite armchair and zigzag single-walled carbon nanotubes attached to various metallic contacts. We have applied the non-equilibrium Green functional formalism with a Tight-Binding and an Extended Hückel Hamiltonian. Our calculations evidence that the contacts block conduction channels for certain types of nanotubes, leading to a reduction of the transmission with respect to the ideal case. We have moreover identified distance between nanotubes and contacts as one of the most important factors of influence for the conduction mechanism. On the other hand, geometrical reconstructions of different types of symmetries between carbon and metal atoms result in having a minor impact on transport.