  We present a QCD-based model where rescattering between final state partons
in deep inelastic scattering leads to events with large rapidity gaps and a
leading proton. In the framework of this model the amplitude for multiple gluon
exchanges is calculated in the eikonal approximation to all orders in
perturbation theory. Both large and small invariant mass M_X limits are
considered. The model successfully describes the precise HERA data on the
diffractive deep inelastic cross section in the whole available kinematical
range and gives new insight into the density of gluons at very small momentum
fractions in the proton.
