  We calculate the three-point functions of pure Landau gauge QCD and
investigate their influence on the propagators. As expected, the ghost-gluon
vertex leads only to minor modifications, while the three-gluon vertex has a
sizeable impact on the mid-momentum regime of the gluon propagator. We describe
an effective model of the three-gluon vertex that includes contributions from
the neglected two-loop diagrams and thus allows to obtain propagators in good
agreement with lattice results. We also determine the three-gluon vertex from
these propagators and find good agreement with lattice results as well. In
turn, these results allow us to assess the effect of the missing two-loop
diagrams in the gluon propagator equation. Finally, we present the first
self-consistent calculation that includes all two-and three-point functions.
