  We discuss the pure gauge Schwinger-Dyson equation for the gluon propagator
in the Landau gauge within an approximation proposed by Mandelstam many years
ago. We show that a dynamical gluon mass arises as a solution. This solution is
obtained numerically in the full range of momenta that we have considered
without the introduction of any ansatz or asymptotic expression in the infrared
region. The vertex function that we use follows a prescription formulated by
Cornwall to determine the existence of a dynamical gluon mass in the light cone
gauge. The renormalization procedure differs from the one proposed by
Mandelstam and allows for the possibility of a dynamical gluon mass. Some of
the properties of this solution, such as its dependence on $\Lambda_{QCD}$ and
its perturbative scaling behavior are also discussed.
