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 can not conclude whether CP Pup is a long period system , all observational evidences point at an intermediate polar ( IP ) type CV .