HP VPN Firewall Appliances VPN Configuration Guide

140
6. Identifying that the destination address of the packet is the tunnel interface and the protocol is AH
or ESP, the forwarding module forwards the packet to the IPsec tunnel interface for
de-encapsulation.
7. The IPsec tunnel interface de-encapsulates the packet, and then delivers the resulting clear text
packet back to the forwarding module.
8. The forwarding module looks up the routing table, and then forwards the clear text packet out of
the physical outbound interface associated with the tunnel interface.
IPsec for IPv6 routing protocols
You can use IPsec to protect routing information and defend against attacks for these IPv6 routing
protocols: OSPFv3, IPv6 BGP, and RIPng. IPsec enables these IPv6 routing protocols to encapsulate
outbound protocol packets and de-encapsulate inbound protocol packets with the AH or ESP protocol.
If an inbound protocol packet is not IPsec protected, or fails to be de-encapsulated, for example, due to
decryption or authentication failure, the routing protocol discards that packet.
You must manually configure SA parameters in an IPsec policy for IPv6 routing protocols. The IKE key
exchange mechanism is applicable only to one-to-one communications. IPsec cannot implement
automatic key exchange for one-to-many communications on a broadcast network, where routers must
use the same SA parameters (SPI and key) to process packets for a routing protocol.
IPsec RRI
IPsec Reverse Route Inject (RRI) enables an IPsec tunnel gateway to automatically add static routes
destined for protected private networks or peer IPsec tunnel gateways to a routing table. In a VPN
network, IPsec RRI can add static routes to VPN instances' routing tables.
IPsec RRI is applicable to gateways, for example, a headquarters gateway that must provide many IPsec
tunnels. It frees you from the tedious work of manually configuring and maintaining static routes for IPsec
tunnels. For example, if you enable RRI on Device A in Figure 97,
Device A can automatically create a
static route to br
anch network 192.168.2.0/24 for the IPsec protected traffic from the headquarters to the
branch. You do not have to manually add the static route (whose destination IP/mask is 192.168.2.0/24
and next hop address is 2.2.2.2) on Device A.
Figure 97 An IPsec VPN
You can advertise the static routes created by IPsec RRI in the internal network. IPsec RRI can quickly
create new routes for forwarding IPsec VPN traffic when an active link fails in a load balanced or stateful
failover environment, or when IPsec VPN traffic cannot reach the peer gateway through the default local
gateway.