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350-401 · Question #521

Refer to the exhibit. Router BRDR-1 is configured to receive the 0.0.0.0/0 and 172.17.1.0/24 networks via BGP and advertise them into OSPF area 0. An engineer has noticed that the OSPF domain is recei

The correct answer is D. router ospf 1 default-information originate always end. To resolve the issue of a BGP-learned default route not being advertised into OSPF, the OSPF process must be explicitly configured to originate default information.

Submitted by tarun92· Mar 6, 2026Infrastructure

Question

Refer to the exhibit. Router BRDR-1 is configured to receive the 0.0.0.0/0 and 172.17.1.0/24 networks via BGP and advertise them into OSPF area 0. An engineer has noticed that the OSPF domain is receiving only the 172.17.1.0/24 route and default route 0.0.0.0/0 is still missing. Which configuration must an engineer apply to resolve the problem?

Exhibits

350-401 question #521 exhibit 1
350-401 question #521 exhibit 2

Options

  • Arouter ospf 1 redistribute bgp 65001 metric 100 route-policy BGP-TO-OSPF end
  • Brouter ospf 1 default-information originate end
  • Crouter ospf 1 default-metric 100 end
  • Drouter ospf 1 default-information originate always end

How the community answered

(46 responses)
  • A
    4% (2)
  • B
    7% (3)
  • C
    17% (8)
  • D
    72% (33)

Why each option

To resolve the issue of a BGP-learned default route not being advertised into OSPF, the OSPF process must be explicitly configured to originate default information.

Arouter ospf 1 redistribute bgp 65001 metric 100 route-policy BGP-TO-OSPF end

While `redistribute bgp` is necessary to bring BGP routes into OSPF, it typically does not by itself originate a default route (0.0.0.0/0) into OSPF, requiring an explicit `default-information originate` command.

Brouter ospf 1 default-information originate end

The `default-information originate` command without `always` will only advertise a default route if the router already has an active default route in its routing table, but `always` provides a more robust guarantee of propagation in all circumstances.

Crouter ospf 1 default-metric 100 end

The `default-metric` command sets the metric for routes being redistributed into OSPF, but it does not enable the advertisement of the default route itself.

Drouter ospf 1 default-information originate always endCorrect

The `default-information originate always` command explicitly instructs the OSPF process to advertise a 0.0.0.0/0 default route into its area, regardless of whether a default route currently exists in the router's IP routing table. This guarantees that the default route received via BGP will be propagated into the OSPF domain, solving the missing default route problem.

Concept tested: OSPF default route origination

Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/command/ospf-cr-book/ospf-cr-d1.html#wp2457053597

Topics

#OSPF redistribution#BGP redistribution#Default route redistribution#default-information originate

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