in a routed configuration, the firebox is put in place with separate logical networks and separate network addresses on its interfaces. routed configuration is used primarily when the number of public ip addresses is limited or when you have dynamic ip addressing on the external interface. for more information on dynamic ip addressing on the external interface, see “dynamic ip support on the external interface” on page 31.

    public servers behind the firebox use private addresses, and traffic is routed using network address translation (nat).

   

    characteristics of a routed configuration:

    1?all interfaces of the firebox must be on different networks. the minimum setup involves the external and trusted interfaces.

    2?the trusted and optional interfaces must be on separate networks and all machines behind the trusted and optional interfaces must be configured with an ip address from that network.

    the benefit of a routed configuration is that the networks are well defined and easier to manage, especially regarding vpns.