MELJUN CORTES NETWORK MANAGEMENT 32

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MELJUN CORTES NETWORK MANAGEMENT 32

  1. 1. Chapter 32 Security in the Internet: IPSec, SSL/TLS, PGP, VPN, and Firewalls MELJUN CORTES32.1
  2. 2. Figure 32.1 Common structure of three security protocols32.2
  3. 3. 32-1 IPSecurity (IPSec) IPSecurity (IPSec) is a collection of protocols designed by the Internet Engineering Task Force (IETF) to provide security for a packet at the network level. Topics discussed in this section: Two Modes Two Security Protocols Security Association Internet Key Exchange (IKE) Virtual Private Network32.3
  4. 4. Figure 32.2 TCP/IP protocol suite and IPSec32.4
  5. 5. Figure 32.3 Transport mode and tunnel modes of IPSec protocol32.5
  6. 6. Note IPSec in the transport mode does not protect the IP header; it only protects the information coming from the transport layer.32.6
  7. 7. Figure 32.4 Transport mode in action32.7
  8. 8. Figure 32.5 Tunnel mode in action32.8
  9. 9. Note IPSec in tunnel mode protects the original IP header.32.9
  10. 10. Figure 32.6 Authentication Header (AH) Protocol in transport mode32.10
  11. 11. Note The AH Protocol provides source authentication and data integrity, but not privacy.32.11
  12. 12. Figure 32.7 Encapsulating Security Payload (ESP) Protocol in transport mode32.12
  13. 13. Note ESP provides source authentication, data integrity, and privacy.32.13
  14. 14. Table 32.1 IPSec services32.14
  15. 15. Figure 32.8 Simple inbound and outbound security associations32.15
  16. 16. Note IKE creates SAs for IPSec.32.16
  17. 17. Figure 32.9 IKE components32.17
  18. 18. Table 32.2 Addresses for private networks32.18
  19. 19. Figure 32.10 Private network32.19
  20. 20. Figure 32.11 Hybrid network32.20
  21. 21. Figure 32.12 Virtual private network32.21
  22. 22. Figure 32.13 Addressing in a VPN32.22
  23. 23. 32-2 SSL/TLS Two protocols are dominant today for providing security at the transport layer: the Secure Sockets Layer (SSL) Protocol and the Transport Layer Security (TLS) Protocol. The latter is actually an IETF version of the former. Topics discussed in this section: SSL Services Security Parameters Sessions and Connections Four Protocols Transport Layer Security32.23
  24. 24. Figure 32.14 Location of SSL and TLS in the Internet model32.24
  25. 25. Table 32.3 SSL cipher suite list32.25
  26. 26. Table 32.3 SSL cipher suite list (continued)32.26
  27. 27. Note The client and the server have six different cryptography secrets.32.27
  28. 28. Figure 32.15 Creation of cryptographic secrets in SSL32.28
  29. 29. Figure 32.16 Four SSL protocols32.29
  30. 30. Figure 32.17 Handshake Protocol32.30
  31. 31. Figure 32.18 Processing done by the Record Protocol32.31
  32. 32. 32-3 PGP One of the protocols to provide security at the application layer is Pretty Good Privacy (PGP). PGP is designed to create authenticated and confidential e-mails. Topics discussed in this section: Security Parameters Services A Scenario PGP Algorithms Key Rings PGP Certificates32.32
  33. 33. Figure 32.19 Position of PGP in the TCP/IP protocol suite32.33
  34. 34. Note In PGP, the sender of the message needs to include the identifiers of the algorithms used in the message as well as the values of the keys.32.34
  35. 35. Figure 32.20 A scenario in which an e-mail message is authenticated and encrypted32.35
  36. 36. Table 32.4 PGP Algorithms32.36
  37. 37. Figure 32.21 Rings32.37
  38. 38. Note In PGP, there can be multiple paths from fully or partially trusted authorities to any subject.32.38
  39. 39. 32-4 FIREWALLS All previous security measures cannot prevent Eve from sending a harmful message to a system. To control access to a system, we need firewalls. A firewall is a device installed between the internal network of an organization and the rest of the Internet. It is designed to forward some packets and filter (not forward) others. Topics discussed in this section: Packet-Filter Firewall Proxy Firewall32.39
  40. 40. Figure 32.22 Firewall32.40
  41. 41. Figure 32.23 Packet-filter firewall32.41
  42. 42. Note A packet-filter firewall filters at the network or transport layer.32.42
  43. 43. Figure 32.24 Proxy firewall32.43
  44. 44. Note A proxy firewall filters at the application layer.32.44

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