PACKETDOJO GUIDES

OSPF neighbor troubleshooting labs

Practice area mismatches, passive interfaces, and missing advertisements in a browser lab.

Map the expected adjacency

Before troubleshooting, identify which device should be a neighbor on each transit link. This turns an empty neighbor table into a specific missing relationship.

Inspect participation and scope

Compare network statements, area membership, and passive-interface settings. Each changes a different part of the protocol's behavior.

Check the service prefix

After restoring the adjacency, verify that the service network appears where it is needed and that the actual forwarding path succeeds.

Protocol reference: OSPF Version 2 — RFC 2328.

PUT THE IDEA TO WORK

A little too quiet

Atlanta campus. Client, partner and service access branches attach to different vertices of a routed core triangle. Service reachability disappeared after an OSPF hardening change. Interface addressing is unchanged and the service uplink still responds locally. Investigate the two service networks from R1: 10.202.0.0/24 to 10.202.10.0/24 (TCP/443), and 10.202.1.0/24 to 10.202.11.0/24 (TCP/8443).

Physical links · Service health not shown

Link addressing (6)

R1 R210.202.16.0/30
R2 R310.202.17.0/30
R3 R510.202.18.0/30
R5 R210.202.19.0/30
R3 R410.202.20.0/30
R5 R610.202.21.0/30

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