ENCOR lab 6
GRE tunnel with OSPF across the internet
Connect two sites over an ISP that knows nothing about their private networks with a GRE tunnel, run OSPF across it, and avoid recursive routing.
About 30 minutes 5 devices 3 tasksAdvanced
Scenario
Site A (R1, LAN 192.168.1.0/24) and Site B (R2, LAN 192.168.2.0/24) each have one public address and a default route to the ISP. The ISP routes only the public /30s, so the private LANs cannot reach each other. Build Tunnel0 between the sites with the addresses 172.16.0.1/30 (R1) and 172.16.0.2/30 (R2), source it from each WAN interface, and run OSPF process 1 over the tunnel to exchange the LANs. Keep the public networks out of OSPF.
Your tasks
- Tunnel0 is up/up on both routers and R1 can ping 172.16.0.2.
- OSPF runs over the tunnel: R1 learns 192.168.2.0/24 through Tunnel0.
- PC1 can ping PC2.
The lab checks the result, not the exact commands. For example, a ping task passes only when the ping really succeeds through the network you built.