← All lab tasks IP Connectivity Fix · Medium ~15 min · 3 devices · 4 tasks · CCNA v1.1 and v2.0
Branch LAN unreachable across three routers: fix the static routes HQ (R1, LAN 192.168.1.0/24) must reach the branch (R3, LAN 192.168.3.0/24) through R2. There is no routing protocol, only static routes. Pings from R1 to 192.168.3.1 fail, and so do pings from R3 to 192.168.1.1. Addresses and cables are correct. Three routing mistakes are spread over the three routers.
R1 Gi0/1 192.168.1.1/24 (HQ LAN) Gi0/0 10.0.12.1/30 to R2 Gi0/0 10.0.12.2/30
Tasks ○ R1 routes 192.168.3.0/24 to the correct next hop (and the wrong route is gone) ○ R2 has a route to 192.168.3.0/24 ○ R3 has a default route back toward R2 ○ ping 192.168.3.1 from R1 and ping 192.168.1.1 from R3 both succeed✓ Network fixed.
Both directions work. Try traceroute 192.168.3.1 from R1 to see each hop.
Hints (open one at a time) Hint 1: follow the packet Start on R1 with show ip route static. Every next hop must be an address on a directly connected subnet. Is 10.0.12.6 on R1’s link to R2?
Hint 2: the middle router A transit router needs a route for every destination it forwards to. Run show ip route on R2 and look for 192.168.3.0/24.
Hint 3: the way back Routing is one way. Replies from the branch need a path home. A single default route on R3 pointing at R2 covers everything upstream.
Full solution R1# configure terminal
R1(config)# no ip route 192.168.3.0 255.255.255.0 10.0.12.6
R1(config)# ip route 192.168.3.0 255.255.255.0 10.0.12.2
R1(config)# end
R2# configure terminal
R2(config)# ip route 192.168.3.0 255.255.255.0 10.0.23.2
R2(config)# end
R3# configure terminal
R3(config)# ip route 0.0.0.0 0.0.0.0 10.0.23.1
R3(config)# end
R1# ping 192.168.3.1
R3# ping 192.168.1.1The simulator follows the routing table hop by hop, so every router on the path needs a route in both directions.
