  We present an analysis of the complex associated system of the high-redshift
QSO HE2347-4342. Absorption features of HI, CIII, CIV, NV, and OVI with up to
16 components occur in the optical spectral range located up to 1500 km/s
redwards from the emission line. Apparently, CIV and NV show the line locking
effect. A quantivative analysis of the line distribution comparing simulated
spectra with randomly distributed doublets reveals, however, no statistical
evidence for its physical reality. Using photoionization calculations to
emulate the observed ion column densities we constrain the quasar's spectral
energy distribution. Absorbers in the velocity range of 200 - 600 km/s can be
modelled successfully with a spectral index of alpha ~ -3 at energies higher
than 3 - 4 Ryd, which is an energy distribution similar to the QSO continuum
suggested by Mathews & Ferland (1987). The analysis of a group of high velocity
absorbers (v > 1300 km/s) leads to a harder energy distribution. The large
amount of helium (log N(HeII) > 16.3) associated with these absorbers implies
that they are responsible for the observed absence of the proximity effect
(Reimers et al. 1997). Clouds located more distant from the quasar may be
shielded from the high energy part of the quasar continuum due to optically
thick absorption shortward of 228 Angstrom by the high velocity absorbers. A
group of absorbers with 900 < v < 1200 km/s, in particular a cloud at 1033
km/s, which has the most reliable column density measurements, can be modelled
neither with photoionzation nor under the assumption of collisionally ionized
gas.
