Capstone: the ticket queue
The branch was built by someone else and several things are broken. Users report: "no internet or HQ access from the LAN", "the new PC can't get an address", and "HQ can't reach the branch LAN". The design is: OSPF area 0 between R1 and R2, DHCP on R1 for the LAN, full reachability. Find and fix every fault. (You have console access to both routers.)
How it works: this is VulnTech NetLab, a network simulator running in your browser. Click a device in the diagram to open its console and type commands, just like on real equipment (? shows help, Tab finishes a word). Click a cable to inspect it. Tasks tick themselves off as you complete them; questions are answered in the box under each task. Your work is kept if you reload; Reset starts the network over.
Solution explanation
Three faults. R1 put the WAN link in area 1 while R2 had it in area 0, so the adjacency never formed (an OSPF area mismatch) - no routes crossed. The DHCP pool handed out 192.168.1.254 as the default router, but R1's LAN address is 192.168.1.1, so clients had a wrong gateway and couldn't leave the LAN. Fixing the area brings up OSPF (both LANs appear as O routes), fixing the gateway and renewing lets PC1 reach HQ.
Show solution
[R1]
enable
configure terminal
router ospf 1
no network 10.0.12.0 0.0.0.3 area 1
network 10.0.12.0 0.0.0.3 area 0
exit
ip dhcp pool BRANCH
default-router 192.168.1.1
exit
end
show ip ospf neighbor
[PC1]
ipconfig /renew
ping 203.0.113.10