Configure the basic system properties and network interfaces on F1 using the skills you learned during the lab on Interiour Routing.
On the Client1 and Polycarp, just use ifconfig and route to set the interface address and add a default route. On Outside1, we shall need to do something a bit different to implement our Fake Internet. On Outside1, use ifconfig as you would normally, but use the following route command:
route add default dev eth0
This basically says “if you don’t have a better route available, send it as a local delivery onto the eth0 link”. Normally, we would have expected Outside1 to send it via a router in its own subnet.
We will need a similar rule for F1:
set system gateway-address 203.0.113.117
This is doing essentially the same thing. Note that the gateway is simply the same IP address of F1’s interface, which seems a bit odd really. In effect, it puts it out on the local link attached to the interface with that IP address.
Once you have configured all interfaces and default routes as appropriate to each system, test that each host can ping its directly attached neighbors. You will also find that ping should work between DMZ and LAN too.
A ping from Client1 to Outside1 will fail, because the Outside1 doesn’t know to send the (return) packets to F1, it just puts them on the local link (our Fake Internet) and so will ARP for Client1, which will fail.
 Another way of achieving the Fake Internet slight-of-hand is to have the prefix-length of Outside1 and F1s’ interfaces on the Fake Internet to be a /0, which puts them in the same subnet.