Configuring OSPF
Figure 11-2 shows a typical OSPF deployment configuration. In this configuration, a PIX
Firewall is operating as an ABR. Because you do not want the information about private
networks sent out on the public interface, LSA filtering is applied to the Internet interface.
NAT is applied only to the inside interface (for the private networks).
In this configuration, the inside interface learns routes from both the DMZ and the outside
interface, but you do not want private routes to be propagated to either the DMZ or the
public interfaces.