  We present new X-ray and optical spectra of the old nova CP Pup (nova Pup
1942) obtained with Chandra and the CTIO 4m telescope. The X-ray spectrum
reveals a multi-temperature optically thin plasma reaching a maximum
temperature of 36$^{+19}_{-16}$ keV absorbed by local complex neutral material.
The time resolved optical spectroscopy confirms the presence of the $\sim$1.47
hr period, with cycle-to-cycle amplitude changes, as well as of an additional
long term modulation which is suggestive either of a longer period or of
non-Keplerian velocities in the emission line regions. These new observational
facts add further support to CP Pup as a magnetic cataclysmic variable (mCV).
We compare the mCV and the non-mCV scenarios and while we cannot conclude
whether CP Pup is a long period system, all observational evidences point at an
intermediate polar (IP) type CV.
