Labs - "Switching and routing" question

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#1

So I mostly feel like this was a good lab, however I saw two issues (One of which I think is just me misunderstanding.

So on I believe the 8/9th question it asks you to use jumphost as a router to link app01/app02 to app03/app04.

However the command sudo ip route add <ip-address> via <jump-host address> is what’s confusing me.

Specifically because the via <jump-host address> is different when you add it in app01/app02 vs app03/app04.

From my understanding we are adding to the routing table to access app03/app04 (from app01/app02) through the jump-host server (using it as a gateway/router?) if thats true then shouldn’t the “via” part be the same for both app01/app02 and app03/app04?

or does jump-host have 2 interfaces with different ip’s?

Thanks!

#2

Any host that serves as a router has 2 or more interfaces with different IPs. The router bridges connections between multiple networks, therefore it must have an interface on each of these networks.

#3

@Alistair_KodeKloud That makes sense. Does it matter which interface you use? As long as you use a different one for each of the 2 “partitioned” group of IP’s?

Im assuming the intention was to use the command ip link show to show the interfaces/ip’s?

#4

You must use the correct interface for each route. app01 and app02 are on one network, so you must use the router’s interface that is on the same network as app01 and app02 to route to the other network

#5

That makes sense. Thank you. I think I just needed a rewatch of the basic networking to make sure that I absorbed everything lol.

#6

Imagine your network data is passengers on a train. The passengers want to go from app01 to app04

  1. They get on the train at station app01
  2. They travel to the router which is an interchange station. They have to get off at the router, on the router’s platform for the line from app01. This is the router’s interface on app01’s network.
  3. They switch platforms at router to the line for app04. This platform is the router’s interface on app04’s network.
  4. They take the train to app04

The ip route instruction basically says that to reach the line on which app03 and app04 are stops, you must go via a platform on app01 and app02 line at router stop. The train board at router says what to do next to actually reach the final destination.

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