  We analyze constraints on parameters characterizing the pre-inflating
universe in an open inflation model with a present slightly open $\Lambda$CDM
universe. We employ an analytic model to show that for a broad class of
inflation-generating effective potentials, the simple requirement that some
fraction of the observed dipole moment represents a pre-inflation isocurvature
fluctuation allows one to set upper and lower limits on the magnitude and
wavelength scale of pre-inflation fluctuations in the inflaton field, and the
curvature of the pre-inflation universe, as a function of the fraction of the
total initial energy density in the inflaton field as inflation begins. We
estimate that if the pre-inflation contribution to the current CMB dipole is
near the upper limit set by the {\it Planck} Collaboration then the current
constraints on $\Lambda$CDM cosmological parameters allow for the possibility
of a significantly open $\Omega_{i} \le 0.4$ pre-inflating universe for a broad
range of the fraction of the total energy in the inflaton field at the onset of
inflation. This limit to $\Omega_{i}$ is even smaller if a larger dark-flow
tilt is allowed.
