Chapter 19 IPSec VPN
ZyWALL USG 50-H User’s Guide
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These modes are illustrated below.
In tunnel mode, the ZyWALL uses the active protocol to encapsulate the entire IP packet. As a
result, there are two IP headers:
• Outside header: The outside IP header contains the IP address of the ZyWALL or remote
IPSec router, whichever is the destination.
• Inside header: The inside IP header contains the IP address of the computer behind the
ZyWALL or remote IPSec router. The header for the active protocol (AH or ESP) appears
between the IP headers.
In transport mode, the encapsulation depends on the active protocol. With AH, the ZyWALL
includes part of the original IP header when it encapsulates the packet. With ESP, however,
the ZyWALL does not include the IP header when it encapsulates the packet, so it is not
possible to verify the integrity of the source IP address.
IPSec SA Proposal and Perfect Forward Secrecy
An IPSec SA proposal is similar to an IKE SA proposal (see
except that you also have the choice whether or not the ZyWALL and remote IPSec router
perform a new DH key exchange every time an IPSec SA is established. This is called Perfect
Forward Secrecy (PFS).
If you enable PFS, the ZyWALL and remote IPSec router perform a DH key exchange every
time an IPSec SA is established, changing the root key from which encryption keys are
generated. As a result, if one encryption key is compromised, other encryption keys remain
secure.
If you do not enable PFS, the ZyWALL and remote IPSec router use the same root key that
was generated when the IKE SA was established to generate encryption keys.
The DH key exchange is time-consuming and may be unnecessary for data that does not
require such security.
Additional Topics for IPSec SA
This section provides more information about IPSec SA in your ZyWALL.
Figure 251
VPN: Transport and Tunnel Mode Encapsulation
Original Packet
IP Header
TCP
Header
Data
Transport Mode Packet
IP Header
AH/ESP
Header
TCP
Header
Data
Tunnel Mode Packet
IP Header
AH/ESP
Header
IP Header
TCP
Header
Data
Содержание ZyWall USG 50-H Series
Страница 2: ......
Страница 10: ...Safety Warnings ZyWALL USG 50 H User s Guide 10...
Страница 28: ...Table of Contents ZyWALL USG 50 H User s Guide 28...
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Страница 34: ...Chapter 1 Introducing the ZyWALL ZyWALL USG 50 H User s Guide 34...
Страница 40: ...Chapter 2 Features and Applications ZyWALL USG 50 H User s Guide 40...
Страница 92: ...Chapter 5 Configuration Basics ZyWALL USG 50 H User s Guide 92...
Страница 130: ...Chapter 6 Tutorials ZyWALL USG 50 H User s Guide 130...
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Страница 156: ...Chapter 8 Interface ZyWALL USG 50 H User s Guide 156 Figure 128 Network Interface Ethernet Edit wan2...
Страница 157: ...Chapter 8 Interface ZyWALL USG 50 H User s Guide 157 Figure 129 Network Interface Ethernet Edit lan1...
Страница 208: ...Chapter 8 Interface ZyWALL USG 50 H User s Guide 208 Figure 161 Network Interface Bridge Add...
Страница 224: ...Chapter 9 Trunks ZyWALL USG 50 H User s Guide 224...
Страница 250: ...Chapter 12 Zones ZyWALL USG 50 H User s Guide 250...
Страница 280: ...Chapter 16 ALG ZyWALL USG 50 H User s Guide 280...
Страница 286: ...Chapter 17 IP MAC Binding ZyWALL USG 50 H User s Guide 286...
Страница 287: ...287 PART III Firewall Firewall 289...
Страница 288: ...288...
Страница 304: ...Chapter 18 Firewall ZyWALL USG 50 H User s Guide 304...
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Страница 313: ...Chapter 19 IPSec VPN ZyWALL USG 50 H User s Guide 313 Figure 238 VPN IPSec VPN VPN Connection Edit IKE...
Страница 356: ...Chapter 21 SSL User Screens ZyWALL USG 50 H User s Guide 356...
Страница 358: ...Chapter 22 SSL User Application Screens ZyWALL USG 50 H User s Guide 358...
Страница 368: ...Chapter 24 L2TP VPN ZyWALL USG 50 H User s Guide 368...
Страница 394: ...Chapter 25 L2TP VPN Example ZyWALL USG 50 H User s Guide 394...
Страница 395: ...395 PART V Application Patrol Application Patrol BWM 397...
Страница 396: ...396...
Страница 421: ...421 PART VI Anti X ADP 423...
Страница 422: ...422...
Страница 429: ...Chapter 27 ADP ZyWALL USG 50 H User s Guide 429 Figure 359 Profiles Traffic Anomaly...
Страница 432: ...Chapter 27 ADP ZyWALL USG 50 H User s Guide 432 Figure 360 Profiles Protocol Anomaly...
Страница 440: ...Chapter 27 ADP ZyWALL USG 50 H User s Guide 440...
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Страница 462: ...Chapter 29 Addresses ZyWALL USG 50 H User s Guide 462...
Страница 474: ...Chapter 31 Schedules ZyWALL USG 50 H User s Guide 474...
Страница 484: ...Chapter 32 AAA Server ZyWALL USG 50 H User s Guide 484...
Страница 506: ...Chapter 34 Certificates ZyWALL USG 50 H User s Guide 506...
Страница 510: ...Chapter 35 SSL Application ZyWALL USG 50 H User s Guide 510...
Страница 511: ...511 PART VIII System System 513...
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Страница 568: ...Chapter 38 Logs ZyWALL USG 50 H User s Guide 568 Figure 464 Maintenance Log Log Setting Edit System Log...
Страница 584: ...Chapter 40 Diagnostics ZyWALL USG 50 H User s Guide 584...
Страница 586: ...Chapter 41 Reboot ZyWALL USG 50 H User s Guide 586...
Страница 596: ...Chapter 43 Product Specifications ZyWALL USG 50 H User s Guide 596...
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Страница 636: ...Appendix A Log Descriptions ZyWALL USG 50 H User s Guide 636...
Страница 640: ...Appendix B Common Services ZyWALL USG 50 H User s Guide 640...
Страница 646: ...Appendix C Importing Certificates ZyWALL USG 50 H User s Guide 646...