Static Routing with Forward and Return Paths
Static Routing Lab
Two LANs connected through a routed transit network
Scenario
LAN A and LAN B are remote networks. Routers initially know only directly connected networks. Your goal is to add explicit routes so traffic can travel to the remote LAN and back.
Minimal addressing for this AddySec version
| Link | Network |
|---|---|
| PC1-R1 LAN | 192.168.10.0/24 |
| R1-R2 transit | 20.21.21.0/30 |
| R2-PC2 LAN | 192.168.20.0/24 |
Use R1 .1 and R2 .2 on the transit. PC1 uses 192.168.10.10/24 with gateway .1; PC2 uses 192.168.20.10/24 with gateway .1.
Step 1 — Prove the failure first
R1# show ip route
R1# ping 192.168.20.10
R1 should not have a route to 192.168.20.0/24 yet.
Step 2 — Add the forward route
R1# configure terminal
R1(config)# ip route 192.168.20.0 255.255.255.0 20.21.21.2
R1(config)# end
R1# show ip route static
Step 3 — Add the return route
R2# configure terminal
R2(config)# ip route 192.168.10.0 255.255.255.0 20.21.21.1
R2(config)# end
R2# show ip route static
Step 4 — End-to-end test
Ping PC2 from PC1. Then use traceroute. Explain each hop using the routing table, not guesswork.
Break it
Delete only the return route on R2. PC1 sends an echo request toward PC2, but what happens to the echo reply? Use routing tables to prove the failure.
Reference
The supplied static-routing lab explicitly demonstrates destination routes and the need for a return path. This shorter two-router exercise preserves that learning objective while making the failure easier to observe.