Comments About Packet Filtering Tutorial

Hi;
Thank you *very much* for this excellent tutorial! Here are a few things 
I would suggest for its improvement:
* State near the beginning explicitly your use of terms for interfaces, 
what they do and how to discover what yours are. The tutorial assumes 
everyone understands this. I did not and this created a lot of confusion 
for me.
* Standardize your use of interfaces. The tutorial goes back and forth 
between a whole plethora of them, adding to the above confusion.
* Explain what things like "port www" mean. This isn't a macro...it 
doesn't have a "$" sign. But how is it a port? It isn't a port number, 
either.
Other than that, excellent. I'm on my third read and long along the way 
to developing a good rules set.
Thanks again,
beno