  By quantitatively fitting simple emission line profile models that include
both atomic opacity and porosity to the Chandra X-ray spectrum of $\zeta$ Pup,
we are able to explore the trade-offs between reduced mass-loss rates and wind
porosity. We find that reducing the mass-loss rate of $\zeta$ Pup by roughly a
factor of four, to 1.5 \times 10^{-6} M_sun/yr, enables simple non-porous wind
models to provide good fits to the data. If, on the other hand, we take the
literature mass-loss rate of 6 \times 10^{-6} M_sun/yr, then to produce X-ray
line profiles that fit the data, extreme porosity lengths -- of $h_{\infty}
\approx 3$ Rstar -- are required. Moreover, these porous models do not provide
better fits to the data than the non-porous, low optical depth models.
Additionally, such huge porosity lengths do not seem realistic in light of 2-D
numerical simulations of the wind instability.
