HP 6125XLG Command Reference Manual page 255

Syntax
encapsulation-mode { transport | tunnel }
undo encapsulation-mode
Default
IP packets are encapsulated in tunnel mode.
Views
IPsec transform set view
Predefined user roles
network-admin
Parameters
transport: Uses the transport mode for IP packet encapsulation.
tunnel: Uses the tunnel mode for IP packet encapsulation.
Usage guidelines
IPsec supports the following encapsulation modes:
Transport mode—The security protocols protect the upper layer data of an IP packet. Only the
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transport layer data is used to calculate the security protocol headers. The calculated security
protocol headers and the encrypted data (only for ESP encapsulation) are placed after the original
IP header. You can use the transport mode when end-to-end security protection is required (the
secured transmission start and end points are the actual start and end points of the data). The
transport mode is typically used for protecting host-to-host communications.
Tunnel mode—The security protocols protect the entire IP packet. The entire IP packet is used to
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calculate the security protocol headers. The calculated security protocol headers and the encrypted
data (only for ESP encapsulation) are encapsulated in a new IP packet. In this mode, the
encapsulated packet has two IP headers. The inner IP header is the original IP header. The outer IP
header is added by the network device that provides the IPsec service. You must use the tunnel
mode when the secured transmission start and end points are not the actual start and end points of
the data packets (for example, when two gateways provide IPsec but the data start and end points
are two hosts behind the gateways). The tunnel mode is typically used for protecting
gateway-to-gateway communications.
The IPsec transform sets at both ends of the IPsec tunnel must have the same encapsulation mode.
The IPsec transform set referenced by the IPsec profile must use the transport mode for packet
encapsulation.
Examples
# Configure the IPsec transform set tran1 to use the transport mode for IP packet encapsulation.
<Sysname> system-view
[Sysname] ipsec transform-set tran1
[Sysname-ipsec-transform-set-tran1] encapsulation-mode transport
Related commands
ipsec transform-set
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