  (Abridged) We use the largest set of globular cluster velocities obtained so
far of any elliptical galaxy to revise and extend the previous investigations
of the dynamics of NGC 1399, the central dominant galaxy of the nearby Fornax
cluster of galaxies. Our sample now comprises velocities for almost 700 GCs
with projected galactocentric radii between 6 and 100 kpc. In addition, we use
velocities published by Bergond et al. (2007). We study the kinematics of the
metal-poor and metal-rich subpopulations and perform spherical Jeans modelling.
  The most important results are: The metal-rich (red) GCs resemble the stellar
field population of NGC 1399 in the region of overlap. Both subpopulations are
kinematically distinct and do not show a smooth transition. It is not possible
to find a common dark halo which reproduces simultaneously the properties of
both subpopulations. Some velocities of blue GCs are only to be explained by
orbits with very large apogalactic distances, thus indicating a contamination
with GCs which belong to the entire Fornax cluster rather than to NGC 1399.
Stripped GCs from nearby elliptical galaxies, particularly NGC 1404, may also
contaminate the metal-poor sample. We argue in favour of a scenario in which
the majority of the blue cluster population has been accreted during the
assembly of the Fornax cluster. The red cluster population shares the dynamical
history of the galaxy itself. Therefore we recommend to use a dark halo based
on the red GCs alone. The dark halo which fits best is marginally less massive
than the halo quoted by Richtler et al. (2004). The comparison with X-ray
analyses is satisfactory in the inner regions, but without showing evidence for
a transition from a galaxy to a cluster halo, as suggested by X-ray work.
