CCNA Foundations: OSPF Day 1 — Single-Area Adjacency

Archive lab

Bring up OSPFv2 adjacency between two branch routers over a point-to-point /30, advertise each site’s user LAN and router loopback in area 0, and verify end-to-end pings succeed from the hosts. The baseline ships with addressing and SSH management ready; you will enable and tune OSPF only.

Learning objectives

• Enable OSPFv2 in a single area (area 0) on a point-to-point transit.
• Set deterministic router-ids using Loopback0 and advertise them.
• Use passive-interface hygiene to limit OSPF to the transit only.
• Verify adjacency, LSAs, and OSPF-learned routes; test host-to-host reachability.

Troubleshooting focus

• Adjacency stuck in INIT or EXSTART: Confirm both sides are in area 0 and the 10.0.12.0/30 transit is actually matched by your OSPF network statements. Ensure the transit interface is not passive on either router.
• No OSPF neighbor at all: Check cabling and IP/mask on Ethernet0/1 at both routers. Verify the subnet is consistent (10.0.12.1/30 and 10.0.12.2/30). Confirm unique router-ids (show ip protocols).
• Routes missing: Confirm the LAN networks are included under OSPF with accurate wildcards. If using passive-interface default, verify the LANs are still advertised even though they are passive.
• Host pings fail but routes exist: Check host IP/gateway settings, switch VLAN assignments (VLAN 10 for Site A ports, VLAN 20 for Site B ports), and interface up/up status on the routers’ LAN ports.