1. Chapter 21 Network Basics for Digital Investigators ©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved.

2. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.1 Map of ARPANET.

3. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.2 Timeline of key events.

4. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.3 Depiction of hosts with NICs connected to a router to form a network.

5. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.4 Hosts connected to a central hub (star typology).

6. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.5 Normal FDDI communication versus backup communication when a host is down (double-ring typology).

7. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.6 Wireless IEEE 802.11 network with a PDA and PC connected to an AP. Also shown is the AP connected to the Internet.

8. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.7 Dissimilar networks connected using a common language to form an internet.

9. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.8 Barbara the Bookie’s Network.

10. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.9 Conceptual depiction of TCP/IP with arrows indicating communication between modules.

11. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.10 A simplified depiction of the Open System Interconnection layers showing where TCP/IP fits.

12. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.11 A conceptual representation of packets in network traffic relating to a single flow being extracted and reconstituted to obtain the data they carry (Casey, 2004).

13. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.12 Graphical synopsis of the OSI reference model.

14. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.13 How a Web browser accesses the Internet as seen through the OSI model.

15. Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.14 NetIntercept (http://www.sandstorm.com) showing components of a Web page both in OSI layers and content recovered from network traffic.http://www.sandstorm.com