CSC 250

1
CSC 250

• Introduction to
• Networking Fundamentals
• Class Meeting 13

2
Network Security Audit

• Presentation by
• Travis Green
• And
• Luke Hatcher

3
The Upcoming Final Exam

• The Exam Format
• Analytical, aka Subjective Portion
• Content
• Problems
• Discussion questions
• Types of exercises you have encountered in the
  homework and written lab exercises
• Completed outside of class (take home)
• Over the weekend
• Use sources identified in the course
• Submit when you arrive at the beginning of class
  on Monday, Jan 24

4
The Final Exam

• The Exam Format / continued
• Quick Response
• Content
• Matching
• Short Answer
• Multiple Choice
• Completed in Class the morning of Monday, the
  24th
• Your last opportunity to convince me how much you
  have learned about networking fundamentals

5
The Final Exam

• Topics Covered
• All material discussed in class and lab sessions
• Textbook Chapters 1 5, 7, 8
• Emphasis on protocols and the services they
  provide
• Why packet switching instead of circuit
  switching?
• Why is TCP/IP prevalent?
• What specific role does each layer in the
  protocol stack play?
• Some historically significant events and
  individuals and their contributions in the
  evolution of networks.

6
The Final Exam

• Preparation Hints
• Complete and review homework questions and
  problems
• Review written lab exercises
• Make an organizational chart which includes
• Each protocol stack layer
• The functions performed at each layer
• The protocols associated with each layer
• The services associated with each protocol and
  how they are implemented
• Questions

7
Chapter 7 Network Security

• Chapter goals
• understand principles of network security
• cryptography and its many uses beyond
  confidentiality
• authentication
• message integrity
• key distribution
• security in practice
• firewalls
• security in application, transport, network, link
  layers

8
Chapter 7 roadmap

• 7.1 What is network security?
• 7.2 Principles of cryptography
• 7.3 Authentication
• 7.4 Integrity
• 7.5 Key Distribution and certification
• 7.6 Access control firewalls
• 7.7 Attacks and counter measures
• 7.8 Security in many layers

9
What is network security?

• Confidentiality only sender, intended receiver
  should understand message contents
• sender encrypts message
• receiver decrypts message
• Authentication sender, receiver want to confirm
  identity of each other
• Message Integrity sender, receiver want to
  ensure message not altered (in transit, or
  afterwards) without detection
• Access and Availability services must be
  accessible and available to users

10
Friends and enemies Alice, Bob, Trudy

• well-known in network security world
• Bob, Alice (lovers!) want to communicate
  securely
• Trudy (intruder) may intercept, delete, add
  messages

Alice
Bob
data, control messages
channel
secure sender
secure receiver
data
data
Trudy
11
Who might Bob, Alice be?

• well, real-life Bobs and Alices!
• Web browser/server for electronic transactions
  (e.g., on-line purchases)
• on-line banking client/server
• DNS servers
• routers exchanging routing table updates
• other examples?

12
There are bad guys (and girls) out there!

• Q What can a bad guy do?
• A a lot!
• eavesdrop intercept messages
• actively insert messages into connection
• impersonation can fake (spoof) source address in
  packet (or any field in packet)
• hijacking take over ongoing connection by
  removing sender or receiver, inserting himself in
  place
• denial of service prevent service from being
  used by others (e.g., by overloading resources)

more on this later
13
Chapter 7 roadmap

• 7.1 What is network security?
• 7.2 Principles of cryptography
• 7.3 Authentication
• 7.4 Integrity
• 7.5 Key Distribution and certification
• 7.6 Access control firewalls
• 7.7 Attacks and counter measures
• 7.8 Security in many layers