Prestige 661H/HW Series User’s Guide
173
Chapter 14 Introduction to IPSec
Figure 79
Transport and Tunnel Mode IPSec Encapsulation
14.3.1 Transport Mode
Transport
mode is used to protect upper layer protocols and only affects the data in the IP
packet. In
Transport
mode, the IP packet contains the security protocol (
AH
or
ESP
) located
after the original IP header and options, but before any upper layer protocols contained in the
packet (such as TCP and UDP).
With
ESP,
protection is applied only to the upper layer protocols contained in the packet. The
IP header information and options are not used in the authentication process. Therefore, the
originating IP address cannot be verified for integrity against the data.
With the use of
AH
as the security protocol, protection is extended forward into the IP header
to verify the integrity of the entire packet by use of portions of the original IP header in the
hashing process.
14.3.2 Tunnel Mode
Tunnel
mode encapsulates the entire IP packet to transmit it securely. A
Tunnel
mode is
required for gateway services to provide access to internal systems.
Tunnel
mode is
fundamentally an IP tunnel with authentication and encryption. This is the most common
mode of operation.
Tunnel
mode is required for gateway to gateway and host to gateway
communications.
Tunnel
mode communications have two sets of IP headers:
•
Outside header
: The outside IP header contains the destination IP address of the VPN
gateway.
•
Inside header
: The inside IP header contains the destination IP address of the final
system behind the VPN gateway. The security protocol appears after the outer IP header
and before the inside IP header.
14.4 IPSec and NAT
Read this section if you are running IPSec on a host computer behind the Prestige.
Summary of Contents for Prestige 661H Series
Page 37: ...Prestige 661H HW Series User s Guide 37 List of Tables...
Page 41: ...Prestige 661H HW Series User s Guide 41 Introduction to DSL...
Page 51: ...Prestige 661H HW Series User s Guide 51 Chapter 1 Getting To Know Your Prestige...
Page 67: ...Prestige 661H HW Series User s Guide 67 Chapter 3 Wizard Setup for Internet Access...
Page 81: ...Prestige 661H HW Series User s Guide 81 Chapter 5 LAN Setup...
Page 125: ...Prestige 661H HW Series User s Guide 125 Chapter 8 Network Address Translation NAT Screens...
Page 143: ...Prestige 661H HW Series User s Guide 143 Chapter 11 Firewalls...
Page 165: ...Prestige 661H HW Series User s Guide 165 Chapter 12 Firewall Configuration...
Page 169: ...Prestige 661H HW Series User s Guide 169 Chapter 13 Content Filtering...
Page 175: ...Prestige 661H HW Series User s Guide 175 Chapter 14 Introduction to IPSec...
Page 203: ...Prestige 661H HW Series User s Guide 203 Chapter 15 VPN Screens...
Page 207: ...Prestige 661H HW Series User s Guide 207 Chapter 16 Remote Management Configuration...
Page 221: ...Prestige 661H HW Series User s Guide 221 Chapter 17 Universal Plug and Play UPnP...
Page 227: ...Prestige 661H HW Series User s Guide 227 Chapter 18 Logs Screens...
Page 241: ...Prestige 661H HW Series User s Guide 241 Chapter 19 Media Bandwidth Management Advanced Setup...
Page 265: ...Prestige 661H HW Series User s Guide 265 Chapter 21 Maintenance...
Page 275: ...Prestige 661H HW Series User s Guide 275 Chapter 23 Menu 1 General Setup...
Page 279: ...Prestige 661H HW Series User s Guide 279 Chapter 24 Menu 2 WAN Backup Setup...
Page 283: ...Prestige 661H HW Series User s Guide 283 Chapter 25 Menu 3 LAN Setup...
Page 287: ...Prestige 661H HW Series User s Guide 287 Chapter 26 Wireless LAN Setup...
Page 293: ...Prestige 661H HW Series User s Guide 293 Chapter 27 Internet Access...
Page 307: ...Prestige 661H HW Series User s Guide 307 Chapter 29 Static Route Setup...
Page 311: ...Prestige 661H HW Series User s Guide 311 Chapter 30 Bridging Setup...
Page 327: ...Prestige 661H HW Series User s Guide 327 Chapter 31 Network Address Translation NAT...
Page 343: ...Prestige 661H HW Series User s Guide 343 Chapter 33 Filter Configuration...
Page 363: ...Prestige 661H HW Series User s Guide 363 Chapter 36 System Information and Diagnosis...
Page 381: ...Prestige 661H HW Series User s Guide 381 Chapter 38 System Maintenance...
Page 385: ...Prestige 661H HW Series User s Guide 385 Chapter 39 Remote Management...
Page 395: ...Prestige 661H HW Series User s Guide 395 Chapter 40 IP Policy Routing...
Page 399: ...Prestige 661H HW Series User s Guide 399 Chapter 41 Call Scheduling...
Page 411: ...Prestige 661H HW Series User s Guide 411 Chapter 42 VPN IPSec Setup...
Page 415: ...Prestige 661H HW Series User s Guide 415 Chapter 43 SA Monitor...
Page 431: ...Prestige 661H HW Series User s Guide 431 Appendix A...
Page 451: ...Prestige 661H HW Series User s Guide 451 Appendix C IP Subnetting...
Page 455: ...Prestige 661H HW Series User s Guide 455 Appendix E Command Interpreter...
Page 461: ...Prestige 661H HW Series User s Guide 461 Appendix F Firewall Commands...
Page 464: ...Prestige 661H HW Series User s Guide Appendix G NetBIOS Filter Commands 464...
Page 465: ...Prestige 661H HW Series User s Guide 465 Appendix G NetBIOS Filter Commands...
Page 479: ...Prestige 661H HW Series User s Guide 479 Appendix H VPN Setup...
Page 482: ...Prestige 661H HW Series User s Guide Appendix I Splitters and Microfilters 482...
Page 483: ...Prestige 661H HW Series User s Guide 483 Appendix I Splitters and Microfilters...
Page 537: ...Prestige 661H HW Series User s Guide 537 Appendix M Internal SPTGEN...