I find a lot of new folks have a hard time with the difference in
port numbers and protocol numbers.
I just went through this with a CC<something-more-than NA>, but with
virtually no hands-on experience a few minutes ago. Very disturbing
when a person can take the higher level tests, but still can't
understand the basics. All they do is use the certification testing
programs and memorize everything they can. 
grrr....
scott