Lecture 3: CSCI E-1 Spring 2013

Lecture 3: CSCI E-1 Spring 2013

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Tommy MacWilliam

February 25, 2013
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Transcript

  1. Computer Science E-1 Lecture 3: Internet

  2. From last time...

  3. http://youtu.be/j84eEjP-RL4

  4. Review: March 4

  5. http://youtu.be/9ntPxdWAWq8

  6. traceroute cnn.com

  7. Clients v. Servers

  8. Routers

  9. Network

  10. None
  11. None
  12. None
  13. Internet Service Provider

  14. None
  15. LAN

  16. WAN

  17. None
  18. traceroute reddit.com

  19. IP Address

  20. 10.251.202.239

  21. 4,294,967,296

  22. “640K ought to be enough for anybody”

  23. IPv4

  24. IPv6

  25. http://www.worldipv6launch.org/

  26. 2001:0db8:85a3:0042: 1000:8a2e:0370:7334

  27. 340,282,366,920,938,463,463,374, 607,431,768,211,456

  28. http://samsclass.info/ipv6/ exhaustion.htm

  29. http://www.google.com/ipv6/ statistics.html#tab=ipv6-adoption

  30. Private IP Address

  31. 10.*.*.* 172.16.*.* 192.168.*.*

  32. NAT

  33. Device Private IP Public IP Source Port Macbook 10.0.0.1 74.125.26.228

    1000 iPhone 10.0.0.2 74.125.26.228 1001 iPad 10.0.0.3 74.125.26.228 1002
  34. NAT Request • request from 10.0.0.1 reaches router

  35. NAT Request • request from 10.0.0.1 reaches router • router

    looks up source port for 10.0.0.1
  36. NAT Request • request from 10.0.0.1 reaches router • router

    looks up source port for 10.0.0.1 • router changes source IP to 74.125.26.228, adds source port 1000
  37. NAT Request • request from 10.0.0.1 reaches router • router

    looks up source port for 10.0.0.1 • router changes source IP to 74.125.26.228, adds source port 1000 • router sends modified request to destination
  38. NAT Response • router receives response to 74.125.26.228 with source

    port 1000
  39. NAT Response • router receives response to 74.125.26.228 with source

    port 1000 • router looks up IP address for source port 1000
  40. NAT Response • router receives response to 74.125.26.228 with source

    port 1000 • router looks up IP address for source port 1000 • router forwards response to original client
  41. http://www.whatismyip.com/

  42. DHCP

  43. DHCP • Client broadcasts “I would like to join”

  44. DHCP • Client broadcasts “I would like to join” •

    Server responds “I can help”
  45. DHCP • Client broadcasts “I would like to join” •

    Server responds “I can help” • Client requests an IP address
  46. DHCP • Client broadcasts “I would like to join” •

    Server responds “I can help” • Client requests an IP address • Server offers client an IP address
  47. DHCP • Client broadcasts “I would like to join” •

    Server responds “I can help” • Client requests an IP address • Server offers client an IP address • Client confirms IP address
  48. None
  49. Connection Speeds

  50. None
  51. Wireless Networks

  52. WEP, WPA, WPA2

  53. 3G, 4G

  54. Firewall

  55. None
  56. VPN

  57. Domains

  58. DNS

  59. HOSTS.TXT

  60. DNS Server

  61. Root DNS Server

  62. root-servers.org

  63. TLD DNS Server

  64. Authoritative Name Server

  65. Domain Resolution • hosts file?

  66. Domain Resolution • hosts file? • cache DNS server?

  67. Domain Resolution • hosts file? • cache DNS server? •

    root DNS server
  68. Domain Resolution • hosts file? • cache DNS server? •

    root DNS server • TLD DNS server
  69. Domain Resolution • hosts file? • cache DNS server? •

    root DNS server • TLD DNS server • authoritative name server
  70. http://www.simpledns.com/lookup- dg.aspx

  71. None
  72. Net Neutrality

  73. None
  74. http://www.popsci.com/technology/article/ 2010-07/order-seven-cyber-guardians- around-world-now-hold-keys-internet

  75. Configuring DNS

  76. None
  77. DNS Records • NS: name servers • MX: email •

    A: IPv4 address • AAAA: IPv6 address • CNAME: domain alias
  78. TLDs

  79. TLD Usage .com Companies .edu Education .gov US Government .info

    Information .mil US Military .net Networks .org Organizations
  80. ccTLDs

  81. ccTLDs • bit.ly: Libya • about.me: Montenegro • del.icio.us: US

    • nic.tm: Turkmenistan
  82. http://gtldresult.icann.org/

  83. Registrars

  84. URL

  85. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome

  86. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Scheme

  87. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Authentication

  88. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Domain

  89. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Port

  90. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Path

  91. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Query String

  92. http://username:password@ foo.example.com:1234/cs/e1/is.html ?fun=yes&boring=no#awesome Fragment

  93. Key-Value Pairs

  94. query=cse1&page=3 • client • the query I want is cse1

    • the page I want is 3 • server • what query and page should I look for?
  95. q=e&1?

  96. URL Encoding

  97. q=e%261%3F

  98. URI

  99. urn:isbn:9780811822749

  100. http://cse1.net/psets/pset3.pdf

  101. API

  102. http://developer.mbta.com/lib/rthr/ red.json

  103. https://developers.facebook.com/ tools/explorer/

  104. http://youtu.be/Ve7_4ot-Dzs

  105. Summary

  106. Networking • router • IP address • ISP • network

    • WAN, LAN • IPv6 • private IP address • NAT • DHCP • 802.11n • 3G, 4G • mbps • firewall • VPN
  107. Domain Name System • DNS • domains • hosts file

    • root DNS server • TLD DNS server • authoritative name server • net neutrality • A record • CNAME record • TLD, ccTLD • registrar • URL • URI • API
  108. Computer Science E-1 Lecture 3: Internet