pci compliance

[kalin m]

hi all...

i'm about to submit a freebsd system to be scanned for pci compliance...

is there any particular gotchas with bsd systems that can be detected at 
the time of pci compliance scanning?
i know they use something like nmap if not nmap itself and i did myself 
on that machine and didn't find anything interesting.
but one of the consultants that was 'advising' the company i work for 
said "we use similar (as in nmap) approach but it's (much) more 
intrusive". anybody knows what does that mean?

thanks...