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COSC1078 Introduction to Information Technology Lecture 21 Internet Security

James Harland james.harland@rmit.edu.au. COSC1078 Introduction to Information Technology Lecture 21 Internet Security. Introduction to IT. 1-4 Introduction, Images, Audio, Video 5-6 Computer Fundamentals Assignment 1, WebLearn Test 1 7 Review 8 Operating Systems WebLearn Test 2

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COSC1078 Introduction to Information Technology Lecture 21 Internet Security

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  1. Intro to IT James Harland james.harland@rmit.edu.au COSC1078 Introduction to Information TechnologyLecture 21Internet Security

  2. Intro to IT Introduction to IT 1-4 Introduction, Images, Audio, Video 5-6 Computer Fundamentals Assignment 1, WebLearn Test 1 7Review 8Operating Systems WebLearn Test 2 9 Operating Systems Assignment 2 10 Internet 11 Internet & Security   WebLearn Test 3 12Future of IT Assignment 3, Peer and Self Assessment

  3. Intro to IT Intro to IT Schedule

  4. Intro to IT Overview • Questions? • Mock Exam • Assignment 3 • Internet Security • Questions?

  5. Intro to IT Mock Exam • 10.00-12.30 (TBC) on Wednesday 2rd June in 10.13.03 • Bring your own paper, pens, etc. • No calculators allowed • Answers will be available from me when you leave Schedule (times to be confirmed): • 10.00 Access to room • 10.15 Reading time commences • 10.30 Writing time commences • 12.30 Exam concludes

  6. Assignment 3 Review (re-) answer What is IT? questions from Tutorial 1 Identify difficult parts of the course Suggest new questions Include favourites from Assignments 1 and 2 Reflect Answer reflection questions from tutorials Research Write about a particular IT topic of your choice (5-6 paragraphs) Lecture 21: Internet Security Intro to IT

  7. Internet Hi Dad! Listen! Hi Dad! Listen! Lisa? Lisa? Lecture 19: Internet: Images Intro to IT

  8. Internet Structure 2 1 3 4 Application Mordor sucks! Mordor sucks! Application 1Mor 2dor 1Mor 2dor Transport Transport 3suc 4ks! 3suc 4ks! 1 2 3 4 Network 3 1 Network 2 4 9 5 6 2 9 5 6 2 Link Link 3 2 4 1 Lecture 21: Internet Security Intro to IT

  9. Internet Structure 1 1Mor 6 6 Lecture 21: Internet Security Intro to IT

  10. Network Layer (Internet Protocol) Real intelligence is in the network layer Adds next destination to packet Not complete list of addresses Sends to next destination Retrieves final destination packets for this node Passes them to the transport layer Routing tables can be updated when disconnections occur Hop counts used to stop endless looping Lecture 21: Internet Security Intro to IT

  11. Transport layer Transmission Control Protocol (TCP) often used User Datagram Protocol (UDP) becoming more common TCP Establishes connection first Send and wait for acknowledgement Reliable Can adjust flow control to avoid congestion Often best for email (which is not real-time) Older Lecture 21: Internet Security Intro to IT

  12. Transport layer UDP Doesn’t establish connection Just sends and forget Efficient No congestion adjustment Works well for DNS lookup Often used for Voice over Internet Protocol (VoIP) applications such as Skype Lecture 21: Internet Security Intro to IT

  13. Internet addresses Unique 32-bit identifier (up to 4,294,967,296) Soon to become 128-bit identifier Managed by Internet Corporation for Assigned Names and Numbers (ICANN) ISPs get “blocks” of addresses 32-bit string represented as N1.N2.N3.N4 where Ni is in the range 0..255 17.12.25.0 means 00010001000011000001100100000000 Lecture 21: Internet Security Intro to IT

  14. Internet addresses Dotted decimal notation is still not very kind to humans … www.sludgefacethemovie.com -> ??.??.??.?? Translation done by name servers which look up the Domain Name System (DNS) Domains such as rmit.edu.au can be structured by the domain owner (eg goanna.cs.rmit.edu.au) Lecture 21: Internet Security Intro to IT

  15. Intro to IT Internet Security pass word fire spam wall patch key logger war virus driving Trojan horse worm phishing proxy

  16. Security vs access It is always atrade-off(a balance between two competing forces) More security means less access More access means less security Redundancy can be either fatal or vital Nothing is perfect!

  17. Freedom vs security `Everything which is not forbidden is allowed’ -- Principle of English Law `Everything which is not allowed is forbidden’ -- Common security principle `Anything not mandatory is forbidden’ -- “military policy” `Anything not forbidden is compulsory’(??) — T.H. White (The Once and Future King)

  18. Intro to IT Conclusion • Work on Assignment 3 • Check whether your security defenses are up to date

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