Test: routing

Check your understanding of the whole course.

Intermediate · 10 min read

Routing is the process a router uses to forward a packet toward a destination on another network. It compares the destination IP address with the routes in its routing table, which can be connected, static or learned from a dynamic routing protocol, and sends the packet to the next hop of the best match.

In simple terms: A router looks at where each packet is going, checks its list of known networks and passes the packet one step closer, like a sorting office forwarding a letter to the next town.

Twelve questions on the whole course. They use the same network as the lessons: R1, R2 and R3 in a line, with LANs 192.168.1.0/24, 192.168.2.0/24 and 192.168.3.0/24. Answer each one and read the explanation. If you get one wrong, go back to the lesson it came from.

Predict · scenario 1

1. A packet crosses R1, R2 and R3. Which field changes at every router?

Predict · scenario 2

2. What does an L route such as 192.168.1.1/32 tell the router?

Predict · scenario 3

3. In O 192.168.3.0/24 [110/3] via 10.0.12.2, what is 3?

Predict · scenario 4

4. Routes: 0.0.0.0/0, 172.16.0.0/12, 172.16.5.0/24. Which is used for 172.16.5.9?

Predict · scenario 5

5. EIGRP and OSPF both offer 10.9.0.0/16. Which is installed by default?

Predict · scenario 6

6. Which command adds a static route to 192.168.3.0/24 through R2?

Predict · scenario 7

7. PC1's ping reaches the server, but no reply comes back. What is the most likely cause?

Predict · scenario 8

8. What does the route 0.0.0.0/0 match?

Predict · scenario 9

9. The primary route is learned by OSPF. Which AD makes a static route a floating backup?

Predict · scenario 10

10. Which type of protocol gives every router the same full map of its area?

Predict · scenario 11

11. What must match for two OSPF routers on a link to become neighbours?

Predict · scenario 12

12. Traceroute from R1 shows hop 1 = 10.0.12.2, then only * * *. Where do you look first?