
Frame Relay Sub-Interface Config Command Set Command Reference Guide
422 © 2003 ADTRAN, Inc. 61950860L1-35D
Functional Notes
When configuring a system to use both the stateful inspection firewall and IKE negotiation for VPN, keep the
following notes 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 AOS data-flow logic.
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.
Usage Examples
The following example applies all crypto maps with the name
MyMap
to the frame-relay interface:
(config-fr 1.16)#
crypto map MyMap
Interfaces (Ethernet, Frame Relay, PPP, local)
Static Filter
(in)
Static Filter
(out)
IPSec
Decrypt/Discard
IPSec
Encrypt
NAT/ACP/
Firewall
Router
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