HP 7000 dl Router manual Copyright 2005 Hewlett-Packard Development Company, L.P 853

SROS Command Line Interface Reference Guide Loopback Interface Configuration Command Set

Functional Notes

When configuring a system to use both the stateful inspection firewall and IKE negotiation for VPN, keep the following information in mind:

When defining the policy-class and associated access-control lists (ACLs) that describe the behavior of the firewall, do not forget to include the traffic coming into the system over a VPN tunnel terminated by the system. The firewall should be set up with respect to the un-encrypted traffic that is destined to be sent or received over the VPN tunnel. The following diagram represents typical Secure Router OS data-flow logic.

Interfaces (Ethernet, Frame Relay, PPP, local)

Static Filter

(in)

IPSec

Decrypt/Discard

NAT/ACP/

Firewall

Router

Static Filter

(out)

IPSec

Encrypt

As shown in the diagram above, data coming into the product is first processed by the static filter associated with the interface on which the data is received. This access-group is a true static filter and is available for use regardless of whether the firewall is enabled or disabled. Next (if the data is encrypted) it is sent to the IPSec engine for decryption. The decrypted data is then processed by the stateful inspection firewall. Therefore, given a terminating VPN tunnel, only un-encrypted data is processed by the firewall.

The ACLs for a crypto map on an interface work in reverse logic to the ACLs for a policy-class on an interface. When specifying the ACLs for a crypto map, the source information is the private local-side, un-encrypted source of the data. The destination information will be the far-end, un-encrypted destination of the data. However, ACLs for a policy-class work in reverse. The source information for the ACL in a policy-class is the far-end. The destination information is the local-side.

5991-2114 © Copyright 2005 Hewlett-Packard Development Company, L.P. 853