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OSPF in depth

Adjacencies, passive interfaces, path cost, and redistribution, then diagnose a stuck neighbor.

6 challenges · ~4 h · every step earns its own verified proof

0/6 solved
Start: An OSPF neighbor won't come up →
  1. An OSPF neighbor won't come upmedium~50 min

    Three routers, one area, one adjacency that won't form. Match what both ends require.

  2. OSPF is talking to the office LANmedium~30 min

    Advertise a LAN without throwing OSPF hellos onto it. Passive interfaces, done right.

  3. Traffic is taking the slow pathmedium~45 min

    Steer traffic onto the fast link by setting cost, keeping the backup in reserve.

  4. The server LAN never reaches OSPFmedium~40 min

    Pull a connected LAN into OSPF without adding a network statement for it.

  5. The rest of the network can't see the external routemedium~40 min

    Carry a static route into OSPF so the rest of the domain learns the external block.

  6. The OSPF neighbors won't come upmedium~45 min

    A neighbor stuck short of full. Work the state machine to the root cause.