Chapter 21 IPSec
VSG1435-B101 Series User’s Guide
262
21.4.2 Encapsulation
The two modes of operation for IPSec VPNs are
Transport
mode and
Tunnel
mode. At the time of writing, the ZyXEL Device supports
Tunnel
mode only.
Figure 122
Transport and Tunnel Mode IPSec Encapsulation
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.
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.
Содержание VSG1435-B101 - V1.10
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Страница 8: ...Safety Warnings VSG1435 B101 Series User s Guide 8 ...
Страница 10: ...Contents Overview VSG1435 B101 Series User s Guide 10 ...
Страница 20: ...Table of Contents VSG1435 B101 Series User s Guide 20 ...
Страница 21: ...21 PART I User s Guide ...
Страница 22: ...22 ...
Страница 42: ...Chapter 2 The Web Configurator VSG1435 B101 Series User s Guide 42 ...
Страница 71: ...71 PART II Technical Reference ...
Страница 72: ...72 ...
Страница 78: ...Chapter 5 Network Map and Status Screens VSG1435 B101 Series User s Guide 78 ...
Страница 150: ...Chapter 8 Home Networking VSG1435 B101 Series User s Guide 150 ...
Страница 154: ...Chapter 9 Static Routing VSG1435 B101 Series User s Guide 154 ...
Страница 178: ...Chapter 11 Policy Forwarding VSG1435 B101 Series User s Guide 178 ...
Страница 196: ...Chapter 12 Network Address Translation NAT VSG1435 B101 Series User s Guide 196 ...
Страница 202: ...Chapter 13 Dynamic DNS Setup VSG1435 B101 Series User s Guide 202 ...
Страница 228: ...Chapter 16 Firewall VSG1435 B101 Series User s Guide 228 ...
Страница 234: ...Chapter 18 Parental Control VSG1435 B101 Series User s Guide 234 ...
Страница 282: ...Chapter 25 Traffic Status VSG1435 B101 Series User s Guide 282 ...
Страница 286: ...Chapter 26 IGMP Status VSG1435 B101 Series User s Guide 286 ...
Страница 294: ...Chapter 28 Remote Management VSG1435 B101 Series User s Guide 294 ...
Страница 298: ...Chapter 29 Time Settings VSG1435 B101 Series User s Guide 298 ...
Страница 302: ...Chapter 30 Logs Setting VSG1435 B101 Series User s Guide 302 ...
Страница 318: ...Chapter 34 Troubleshooting VSG1435 B101 Series User s Guide 318 ...
Страница 348: ...Appendix A Setting up Your Computer s IP Address VSG1435 B101 Series User s Guide 348 ...
Страница 358: ...Appendix B IP Addresses and Subnetting VSG1435 B101 Series User s Guide 358 ...
Страница 368: ...Appendix C Pop up Windows JavaScripts and Java Permissions VSG1435 B101 Series User s Guide 368 ...
Страница 384: ...Appendix D Wireless LANs VSG1435 B101 Series User s Guide 384 ...
Страница 412: ...Index VSG1435 B101 Series User s Guide 412 ...