Configuring An Ipsec Policy - H3C S5500-EI Series Security Configuration Manual

Step
5. Specify the IP packet
encapsulation mode
for the IPsec proposal
NOTE:
Changes to an IPsec proposal affect only SAs negotiated after the changes. To apply the changes to
•
existing SAs, execute the reset ipsec sa command to clear the SAs so that they can be set up using the
updated parameters.
• Only when a security protocol is selected, can you configure security algorithms for it. For example, you
can specify the ESP-specific security algorithms only when you select ESP as the security protocol. ESP
supports three IP packet protection schemes: encryption only, authentication only, or both encryption
and authentication. In FIPS mode, you must use both ESP encryption and authentication.

Configuring an IPsec policy

IPsec policies define which IPsec proposals should be used to protect which data flows. An IPsec policy
is uniquely identified by its name and sequence number.
IPsec policies fall into two categories:
Manual IPsec policy—The parameters are configured manually, such as the keys, the SPIs, and the
•
IP addresses of the two ends in tunnel mode.
IPsec policy that uses IKE—The parameters are automatically negotiated through IKE. (Available
•
only in FIPS mode.)
Configuring a manual IPsec policy
To guarantee successful SA negotiations, follow these guidelines when configuring manual IPsec policies
at the two ends of an IPsec tunnel:
The IPsec policies at the two ends must have IPsec proposals that use the same security protocols,
•
security algorithms, and encapsulation mode.
The remote IP address configured on the local end must be the same as the IP address of the remote
•
end.
At each end, configure parameters for both the inbound SA and the outbound SA, and make sure
•
that different SAs use different SPIs.
• The local inbound SA must use the same SPI and keys as the remote outbound SA. The same is true
of the local outbound SA and remote inbound SA.
The keys for the local and remote inbound and outbound SAs must be in the same format. For
•
example, if the local inbound SA uses a key in characters, the local outbound SA and remote
inbound and outbound SAs must use keys in characters.
Command
encapsulation-mode { transport | tunnel }
287
Remarks
Optional.
Tunnel mode by default.
Transport mode applies
only when the source
and destination IP
addresses of data flows
match those of the IPsec
tunnel.
IPsec for IPv6 routing
protocols supports only
the transport mode.