  We report on two ASCA observations of the high-mass X-ray binary pulsar OAO
1657-415. A short observation near mid-eclipse caught the source in a
low-intensity state, with a weak continuum and iron emission dominated by the
6.4-keV fluorescent line. A later, longer observation found the source in a
high-intensity state and covered the uneclipsed through mid-eclipse phases. In
the high-intensity state, the non-eclipse spectrum has an absorbed continuum
component due to scattering by material near the pulsar and 80 per cent of the
fluorescent iron emission comes from less than 19 lt-sec away from the pulsar.
We find a dust-scattered X-ray halo whose intensity decays through the eclipse.
We use this halo to estimate the distance to the source as 7.1 +/- 1.3 kpc.
