ZyWALL 70 User’s Guide
232
Chapter 13 Introduction to IPSec
Figure 106
Transport and Tunnel Mode IPSec Encapsulation
13.3.1 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.
13.3.2 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.
13.4 IPSec and NAT
Read this section if you are running IPSec on a host computer behind the ZyWALL.
Summary of Contents for ZyWALL 70
Page 1: ...ZyWALL 70 Internet Security Appliance User s Guide Version 3 64 3 2005 ...
Page 2: ......
Page 38: ...ZyWALL 70 User s Guide 38 List of Figures ...
Page 46: ...ZyWALL 70 User s Guide 46 List of Tables ...
Page 74: ...ZyWALL 70 User s Guide 74 Chapter 2 Introducing the Web Configurator ...
Page 92: ...ZyWALL 70 User s Guide 92 Chapter 3 Wizard Setup ...
Page 102: ...ZyWALL 70 User s Guide 102 Chapter 4 LAN Screens ...
Page 108: ...ZyWALL 70 User s Guide 108 Chapter 5 Bridge Screens ...
Page 130: ...ZyWALL 70 User s Guide 130 Chapter 6 Wireless LAN ...
Page 136: ...ZyWALL 70 User s Guide 136 Chapter 7 WAN Screens Figure 45 WAN General ...
Page 155: ...ZyWALL 70 User s Guide Chapter 7 WAN Screens 155 Figure 55 Dial Backup Setup ...
Page 234: ...ZyWALL 70 User s Guide 234 Chapter 13 Introduction to IPSec ...
Page 275: ...ZyWALL 70 User s Guide Chapter 15 Certificates 275 Figure 125 My Certificate Details ...
Page 294: ...ZyWALL 70 User s Guide 294 Chapter 16 Authentication Server Figure 136 Local User Database ...
Page 314: ...ZyWALL 70 User s Guide 314 Chapter 17 Network Address Translation NAT ...
Page 318: ...ZyWALL 70 User s Guide 318 Chapter 18 Static Route ...
Page 324: ...ZyWALL 70 User s Guide 324 Chapter 19 Policy Route ...
Page 340: ...ZyWALL 70 User s Guide 340 Chapter 20 Bandwidth Management ...
Page 376: ...ZyWALL 70 User s Guide 376 Chapter 22 Remote Management ...
Page 390: ...ZyWALL 70 User s Guide 390 Chapter 24 Logs Screens Figure 194 Log Settings ...
Page 413: ...ZyWALL 70 User s Guide Chapter 25 Maintenance 413 Figure 216 Restart Screen ...
Page 414: ...ZyWALL 70 User s Guide 414 Chapter 25 Maintenance ...
Page 440: ...ZyWALL 70 User s Guide 440 Chapter 28 WAN and Dial Backup Setup ...
Page 456: ...ZyWALL 70 User s Guide 456 Chapter 31 DMZ Setup ...
Page 460: ...ZyWALL 70 User s Guide 460 Chapter 32 Route Setup ...
Page 470: ...ZyWALL 70 User s Guide 470 Chapter 33 Remote Node Setup ...
Page 522: ...ZyWALL 70 User s Guide 522 Chapter 39 System Information Diagnosis ...
Page 538: ...ZyWALL 70 User s Guide 538 Chapter 40 Firmware and Configuration File Maintenance ...
Page 550: ...ZyWALL 70 User s Guide 550 Chapter 42 Remote Management ...
Page 558: ...ZyWALL 70 User s Guide 558 Chapter 43 IP Policy Routing ...
Page 573: ...ZyWALL 70 User s Guide Chapter 45 Troubleshooting 573 Figure 360 Java Sun ...
Page 574: ...ZyWALL 70 User s Guide 574 Chapter 45 Troubleshooting ...
Page 582: ...ZyWALL 70 User s Guide 582 Appendix B Removing and Installing a Fuse ...
Page 602: ...ZyWALL 70 User s Guide 602 Appendix D IP Subnetting ...
Page 608: ...ZyWALL 70 User s Guide 608 Appendix F PPTP ...
Page 626: ...ZyWALL 70 User s Guide 626 Appendix H Triangle Route ...
Page 656: ...ZyWALL 70 User s Guide 656 Appendix K Importing Certificates ...
Page 658: ...ZyWALL 70 User s Guide 658 Appendix L Command Interpreter ...
Page 664: ...ZyWALL 70 User s Guide 664 Appendix M Firewall Commands ...
Page 668: ...ZyWALL 70 User s Guide 668 Appendix N NetBIOS Filter Commands ...
Page 674: ...ZyWALL 70 User s Guide 674 Appendix P Brute Force Password Guessing Protection ...
Page 696: ...ZyWALL 70 User s Guide 696 Appendix R Log Descriptions ...