
208
Chapter 13 VPN
NN47922-500
Encapsulation
The two modes of operation for IPSec VPNs are
Transport
mode and
Tunnel
mode.
Figure 66
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 VPN
switch to VPN switch and host to VPN switch communications.
Tunnel
mode
communications have two sets of IP headers:
Summary of Contents for BSR222
Page 28: ...28 Tables NN47922 500 ...
Page 50: ...50 Chapter 2 Introducing the WebGUI NN47922 500 ...
Page 66: ...66 Chapter 3 Wizard setup NN47922 500 ...
Page 92: ...92 Chapter 5 System screens NN47922 500 ...
Page 104: ...104 Chapter 6 LAN screens NN47922 500 ...
Page 154: ...154 Chapter 9 Static Route screens NN47922 500 ...
Page 196: ...196 Chapter 11 Firewall screens NN47922 500 ...
Page 212: ...212 Chapter 13 VPN NN47922 500 Figure 68 Summary IP Policies ...
Page 256: ...256 Chapter 13 VPN NN47922 500 Figure 82 VPN Client Termination advanced ...
Page 260: ...260 Chapter 13 VPN NN47922 500 ...
Page 264: ...264 Chapter 14 Certificates NN47922 500 Figure 84 My Certificates ...
Page 290: ...290 Chapter 14 Certificates NN47922 500 Figure 95 Trusted remote host details ...
Page 314: ...314 Chapter 16 IEEE 802 1x NN47922 500 ...
Page 318: ...318 Chapter 17 Authentication server NN47922 500 Figure 107 Local User database edit ...
Page 326: ...326 Chapter 17 Authentication server NN47922 500 ...
Page 374: ...374 Chapter 20 Logs Screens NN47922 500 Figure 151 Log settings ...
Page 384: ...384 Chapter 20 Logs Screens NN47922 500 ...
Page 402: ...402 Chapter 22 Maintenance NN47922 500 Figure 170 Restart screen ...