CCNP Infrastructure Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  ip ospf database-filter all out

  Why it's wrong here

  The command 'ip ospf database-filter all out' filters out outgoing Link State Advertisements (LSAs) on an interface, which is used to reduce flooding on redundant interfaces. It has no effect on DR/BDR election. This command is unrelated to the election process and would not prevent a router from becoming DR or BDR.

• ✗

  ip ospf network point-to-point

  Why it's wrong here

  Configuring the OSPF network type as point-to-point eliminates the DR/BDR election entirely, but it also changes the network type to point-to-point, which is not appropriate for a multiaccess network. This would affect adjacency formation and might not be desired if the segment is truly multiaccess. The scenario specifically asks to prevent certain routers from becoming DR/BDR, not to change the network type.

• ✗

  ip ospf priority 1

  Why it's wrong here

  Setting the OSPF priority to 1 is the default value and makes the router eligible to become DR or BDR. It does not prevent participation in the election. In fact, a priority of 1 is lower than higher values, but if all routers have priority 1, the one with the highest router ID wins. This does not meet the requirement to exclude specific routers from becoming DR or BDR.

• ✓

  ip ospf priority 0

  Why this is correct

  Setting the OSPF priority to 0 on an interface makes that router ineligible to become DR or BDR. This is the correct way to prevent a router from participating in the DR/BDR election. The router will still form adjacencies and exchange routing information, but it will remain a DROTHER. This setting is commonly used on routers that should not be DR/BDR, such as those with lower processing power or at the edge of the network.