[Year 12 SofDev] Re: SD VITTA exam 2, multichoice #1

[Kevork Krozian]

Hi James, 

Your students are right.

  Not a brilliant question as there are outgoing and incoming ports. A firewall can block incoming and outgoing ports and it is necessary to know which one is required to achieve required results. 
If a standard install has been used, to browse a web site you need a destination port of 80 to be accessible. To block an incoming port 80 will have no effect on a browser going out to a web site as it will only block incoming requests to an internal web site. When a client browser goes out to a web site the destination port is 80 but the source port is the next available port from 49152 to 65,535. Ports from 1024 to 49151 are registered ports. Ports 1 to 1023 are well known ports and have specific services.

 If outgoing port 80 is blocked and nothing else has changed ( port on which http protocol is accessed ), then web traffic that uses the http protocol will stop.
Other traffic that uses different ports such as at the end of the address eg. http://www.xyz.com.au:81 or ftp://ftp.xyz.com.au  or gopher://abc.xyz.com.au, if   supported by the browser in question or any other protocols will still work.
So the answer should have been written as 

   B. Can use the browser but web based access of http:// protocol of the internet will stop.

 (  This is Cisco CCNA Curriculum Semester 2 and also Semester 4 ) . In this time of election advertising, this is written and spoken by Cisco candidate K. Krozian CCNA Melbourne - no affiliation with either the ALP or Liberal parties . 

Regards
Kevork

>>> "James GIBNEY" <jgy at sthelena.vic.edu.au> 18/10/2007 11:12 am >>>
HI all,
 
three has there been some discussion in my class about question 6 in the multiple choice in sample exam 2. I have two students that are adamant that answer B is not entirely incorrect because they say you can still access the internet, web based mail &  FTP sites if port 80 is blocked. 
 
Regards
 
Jim
 
James Gibney
ICT Coordinator
St Helena Secondary College
Wallowa Rd
Eltham Nth 3095
Ph 03 94388500
Fax 03 94388555
email: jgy at sthelena.vic.edu.au 
P Please consider the environment before printing this email


________________________________

From: sofdev-bounces at edulists.com.au on behalf of Timmer-Arends
Sent: Wed 17/10/2007 5:52 PM
To: Year 12 Software Development Teachers' Mailing List
Subject: Re: [Year 12 SofDev] Re: SD VITTA exam 2, multichoice #1


I know it's pedantic but I'm going to write it anyway:

Kevin wrote:
All programs can be written using these very simple constructs.
1. Sequence 
2. Repetition (aka iteration or Loops) 
3. Conditional Branching 
4. Combined Branching and Repetition 

Actually only three basic constructs are required to write any program: 1, 2 and 3.
4 is composed of two basic constructs (ie 2 and 3)

And Frank wrote:
The following implementation of a while loop that Mark Kelly found the other day, which is actually a Repeat..Until loop in your theoretical sense but using different key words, says it all....
Do
..
Loop While <condition>

This loop is subly different from a Repeat..Until (and as far as I know only available in MS versions of BASIC). It will execute the body once and then after only WHILE the condition IS TRUE. A Repeat..Until executes the body once and then continues looping UNTIL the condition BECOMES TRUE.
 
Personally, I don't think the post-test WHILE (or MS xxxBASIC's pre-test UNTIL) ought ever be shown to students! 
 
Regards
Robert T-A
Brighton SC
 
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