Let’s Communicate

Personas

Bob, a Browser

• Process on some Internet host

  Figure under CC0 1.0

• Host with one network card
  • IP address 10.0.0.42
  • MAC address 0:0:0:0:0:42
  • Default router with IP address 10.0.0.1
  • Name server with IP address 10.0.0.2

Routers: Rolf and Rosie

• Each with lots of network cards, two relevant here

  “Switch with cable nest” by Justin Smith under CC BY-SA 2.5; from Wikimedia Commons

  • Rolf, first network card
    • IP address 10.0.0.1
    • MAC address 0:0:0:0:0:1
  • Rolf, second network card
    • IP address 128.42.42.1
    • MAC address 0:0:0:0:42:1
  • Rosie, first network card
    • IP address 128.42.42.2
    • MAC address 0:0:0:0:42:2
  • Rosie, second network card
    • IP address 128.176.6.1
    • MAC address 0:0:0:0:6:1

Sarah, the Web Server

• DNS name www.wwu.de, listening on TCP port 80

  Figure under Public domain

• One network card
  • IP address 128.176.6.250
  • MAC address 0:0:0:0:6:250

Eve, a curious Eavesdropper

• One network card

  Figure under CC0 1.0

  • IP address 10.0.0.5
  • MAC address 0:0:0:0:0:5

Mallory, the Malicious Attacker

• One network card

  “Anonymous-Hacker” by Frank Schwichtenberg under CC BY 4.0; from Wikimedia Commons

  • IP address 10.0.0.6
  • MAC address 0:0:0:6:6:6

Supporting Roles

• Dave, DNS server at IP address 10.0.0.2
• TCP/IP interfaces as necessary
  • E.g., java.net.Socket with Socket(IPAddressOrHostName, Port)
    • Standard interface
    • Vs Internet architecture?
• More characters as necessary

Task

• Send request from browser Bob to Web server Sarah
  • Use HTTP request GET /exam-solutions.html HTTP/1.1
    • More on HTTP in separate presentation
    • Maybe tell a story involving all personas/roles

      • You may want to change the name of the Web server and choose a suggestive name for the requested resource …

        Figure under CC0 1.0

Persona Summary

• Endpoints
  • Sarah, server www.wwu.de, 128.176.6.250, 0:0:0:0:6:250
  • Bob, browser, 10.0.0.42, 0:0:0:0:0:42
  • Dave, DNS server 10.0.0.2, 0:0:0:0:0:2
• Routers
  • Rolf
    • 10.0.0.1 with 0:0:0:0:0:1 and 128.42.42.1 with 0:0:0:0:42:1
  • Rosie
    • 128.42.42.2 with 0:0:0:0:42:2 and 128.176.6.1 with 0:0:0:0:6:1
• Eve, eavesdropper, 10.0.0.5, 0:0:0:0:0:5
• Mallory, malicious attacker, 10.0.0.6, 0:0:0:6:6:6

License Information

This document is part of a larger course. Source code and source files are available on GitLab under free licenses.