4.3: suppressing OSPF Hellos

in EIGRP the use of passive-interface stops HELLO packets from being sent across.
It is recommended to use the the distribute-list to supress outgoing updates.

For OSPF, is the recommended approach then to use ip ospf database-filter all out if we still want HELLO packets to be sent out?


  • For RIP the passive-interface command prevents any RIP packets from being sent out, but the RIP process still receives any routes sent by neighboring routers.

    For EIGRP the passive-interface command prevents the establishment of an adjacency - no routes will be sent or received on the passive interface.

    For OSPF the passive-interface command prevents any hellos or LSAs from being sent out the passive interface - this allows the ip address of the interface to be in an OSPF area without attempting to establish adjacency.

    For OSPF "ip ospf demand-circuit" under the interface will suppress hello packets after the adjacency has been established.

    For OSPF "ip ospf flood-reduction" sets the "DoNotAge" flag in the LSAs sent out so they do not need to be refreshed - hello packets would still be sent.

    For OSPF "ip ospf database-filter all out" will allow an adjacency to form and will receive LSAs from the neighbor(s) on the interface, but will not send any LSAs out to neighbors - hello packets will still be sent.

    You can also use the "neighbor a.b.c.d database-filter all out" under the OSPF process to prevent sending LSAs to a particular neighbor.

    Read the task carefully and select the appropriate option to satisfy the requirements of the task.

  • thanks Darrell!

    "passive-interface" has an effect on adjacency establishment for the link state protocols.

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