PA38 et al,
For brevity, I'll just refer you to
www.grc.com where there is some very good information on exactly the things you're concerned about. I did put this in an earlier thread
http://www.pprune.org/ubb/NonCGI/For...ML/000199.html which has been (I hope) useful.
Do try the steps/measures suggested "probe my ports" etc. and you may get some peace of mind.
Best wishes.