  We study the dc conductivity of a weakly disordered 2d Dirac electron gas
with two bands and two spectral nodes, employing a field theoretical version of
the Kubo--Greenwood conductivity formula. In this paper we are concerned with
the question how the internode scattering affects the conductivity. We use and
compare two established techniques for treating the disorder scattering: The
perturbation theory, there ladder and maximally crossed diagrams are summed up,
and the functional integral approach. Both turn out to be entirely equivalent.
For a large number of random potential configurations we have found only two
different conductivity scenarios. Both scenarios appear independently of
whether the disorder does or does not create the internode scattering. In
particular we do not confirm the conjecture that the internode scattering tends
to Anderson localization.
