Study Student Guide
Module A
Networking Concepts
Overview
The broad goal of this module is to review networking concepts. Because the review is designed
done to prepare you to deal with networking concepts in the security context, there are many
notes about the security implications of networking individual concepts. It is suggested that you
do this review before Chapter 3, which is the first chapter to deal with networking concepts.
Learning Suggestions
Special Issues
If you do not have networking as a prerequisite or co-requisite, this material will be challenging
for you. However, without a decent knowledge of networking, it is impossible to master security
today.
If you have had networking, you probably will find that you forgot a lot of what you
learned, so even you will be challenged. Even if you took a networking course, you may not have
seen some topics, such as TCP sequence numbers and acknowledgement numbers, which are
important in networking.
Flow of Material
Module A covers the following network topics:
A sampling of networks to show the main elements of networks.
Network protocols and vulnerabilities. This is a pure security topic.
Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall
Module A: Networking Concepts
Corporate Computer and Network Security, 2nd edition
Raymond R. Panko
Core layers in layered standards architecture. This section divides network protocols into
single-network protocols, internet protocols, and application protocols.
Standards architectures. This section introduces the OSI and TCP/IP standards
architectures. It then discusses the hybrid TCP/IPOSI standards architecture that most
real organizations use.
Single-network standards. This section looks at physical and data link layer standards,
including switch operation, transmission media, and switch supervisory standards.
Internetwork standards. This section introduces the standards used in internetworking.
This is followed by sections on the Internet Protocol (IP), TCP, UDP, and TCP/IP
supervisory standards. Although these are being listed in a single bullet point, they
collectively make up the majority of the chapter.
Application standards. This section covers application standards in general and looks
specifically at HTTP, HTML, e-mail, Telnet, FTP, and SSH. It notes the security issues
regarding this standard.
Learning Aids in the Book
The book has a number of features that can help you learn the material.
Bite-Sized Sections. The chapters are divided into small sections with headings. Teachers
tend to hate it, but students usually like it. It allows them to learn individual chunks of
information and orients them to where they are in longer discussions.
Test Your Understanding Questions. After each section or subsection, there are Test Your
Understanding questions. As the name suggests, these questions are designed to let you
know if you understand the material you have just read. The multiple choice questions
and true/false questions are all taken from the Test Your Understanding and End-ofChapter questions.
Definitions. Important or difficult ideas are often set off in smaller type with a rule line
before and after. Be absolutely sure you absolutely know these concepts, and study them
before exams.
Figures. The figures cover nearly all important concepts in the book and show their
interrelationships. If you already know the material fairly well, the figures are great ways
to see how the topics fit together. If you can explain the figures, you probably have a
good working knowledge of the chapter.
End of Chapter Questions. The questions at the end of the chapter are designed to have
you integrate or really understand what you have learned. If you do them right, you will
get real ah moments.
Studying ha the Material
Students tend to have several problems with the material in this and other chapters.
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Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall
Module A: Networking Concepts
Corporate Computer and Network Security, 2nd edition
Raymond R. Panko
There is a lot of material to master. Mastering it will take a lot of time and effort. In
addition, you cant cherry pick to look for the important concepts.
The most successful students read a section carefully, then stop to do the Test Your
Understanding questions after the section. If they have any doubt, they go back over the
material. This way, they have mastered the concepts, which later material in the chapter
will probably require.
Some of the material is abstract. The problem with abstract material is that you dont
have a mental framework for understanding it. The solution, painful as it is, is to go over
it several times, if possible hours or days apart. Things gradually become clearer as you
brain develops a framework. Keep at it until you really understand individual concepts.
Hazy notions arent enough. Try to come up with examples.
Some material, such as the creation of digital signatures in Chapter 3, involves a series of
steps. Many students have a difficult time with such material. Their eyes glaze over after
one or two steps. The key again is to go over it multiple times. Learn the details of each
step. Then focus on the overview of how the pieces fit together into a process. Repeat
until you have a solid understanding and can explain it to someone else.
Thought questions require you to understand, integrate, and apply the concepts that you
learned in the chapter. Even if you have a solid understanding, thought questions will
require you to put things together. Dont give up if it doesnt come to you right away.
Write down what you know from the question, what you need to find, and what you
learned in the chapter. If this seems complicated, it is. It is also what you will be doing
for the rest of your life.
In troubleshooting questions, dont try to find the answer immediately. Come up with a
list of possible causes. Then try to eliminate as many of them as you can by logic. Then
figure out how to test the rest. Successful troubleshooters make sure they understand the
situation and list many alternatives before they begin to explore one approach to solving
the problem. Inexperienced troubleshooters go down one dead-end road after another and
take far longer.
A lot of material consists of comparing and contrasting things that are similar but also
different. Learning to master such material is critical in working life. IT people in all job
specialties have to choose between several ways to implement a solution, and they cannot
even understand problems without understanding similarities and differences between
possible attacks. The best way to understand similar but dissimilar concepts is to create
boxes comparing and contrasting them. The book has done some of this for you, but
dont try to memorize things. Try to really understand them. The following is a way to
think about viruses and worms, for example.
Viruses
Worms
Directly Propagating Worms
Attach themselves to other programs
Yes
No
No
Can spread via e-mail
Yes
Yes
NA
Cam propagate directly
No
No, in general
Yes
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Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall
Module A: Networking Concepts
Corporate Computer and Network Security, 2nd edition
Raymond R. Panko
Can spread very rapidly
No
No
Yes
Can be stopped by antivirus programs (at
least usually)
Yes
Yes
NA
Can only be stopped by firewalls and
vulnerability patching
No
No
Yes
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Copyright 2010 Pearson Education, Inc. Publishing as Prentice Hall