Configuring An Ipsec Transform Set - HP FlexNetwork 10500 Series Security Configuration Manual

permit statement are processed. Other packets are dropped. If ACL checking for
de-encapsulated IPsec packets is disabled, the de-encapsulated packets are not compared
against the ACL rules and are directly processed by other modules.
When defining ACL rules for IPsec, follow these guidelines:
•
Permit only data flows that need to be protected and use the any keyword with caution. With the
any keyword specified in a permit statement, all outbound traffic matching the permit statement
will be protected by IPsec. All inbound IPsec packets matching the permit statement will be
received and processed, but all inbound non-IPsec packets will be dropped. This will cause all
the inbound traffic that does not need IPsec protection to be dropped.
•
Avoid statement conflicts in the scope of IPsec policy entries. When creating a deny statement,
be careful with its matching scope and matching order relative to permit statements. The policy
entries in an IPsec policy have different match priorities. ACL rule conflicts between them are
prone to cause mistreatment of packets. For example, when configuring a permit statement for
an IPsec policy entry to protect an outbound traffic flow, you must avoid the situation that the
traffic flow matches a deny statement in a higher priority IPsec policy entry. Otherwise, the
packets will be sent out as normal packets. If they match a permit statement at the receiving
end, they will be dropped by IPsec.
Mirror image ACLs
To make sure SAs can be set up and the traffic protected by IPsec can be processed correctly
between two IPsec peers, create mirror image ACLs on the IPsec peers.
If the ACL rules on IPsec peers do not form mirror images of each other, SAs can be set up only
when both of the following requirements are met:
•
The range specified by an ACL rule on one peer is covered by its counterpart ACL rule on the
other peer.
•
The peer with the narrower rule initiates SA negotiation. If a wider ACL rule is used by the SA
initiator, the negotiation request might be rejected because the matching traffic is beyond the
scope of the responder.

Configuring an IPsec transform set

An IPsec transform set, part of an IPsec policy, defines the security parameters for IPsec SA
negotiation, including the security protocol, encryption algorithms, and authentication algorithms.
Changes to an IPsec transform set 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 by using the updated parameters.
To configure an IPsec transform set:
Step
1. Enter system view.
2. Create an IPsec
transform set and enter
its view.
3. Specify the security
protocol for the IPsec
transform set.
Command
system-view
ipsec transform-set
transform-set-name
protocol { ah | ah-esp | esp }
284
Remarks
N/A
By default, no IPsec transform set
exists.
Optional.
By default, the IPsec transform
set uses ESP as the security
protocol.