Which OSPF command causes a router to originate a default route into the OSPF domain?

Which OSPF command causes a router to originate a default route into the OSPF domain?

• A. default-information originate
• B. redistribute static
• C. network
• D. area

Answer: (A)

In OSPF, to have a router advertise a default route to the rest of the domain, you use the default-information originate command. This instruction causes a 0.0.0.0/0 route to be injected into OSPF, so neighboring routers learn how to forward traffic toward destinations beyond their own knowledge. The effect depends on having a default route in the router’s own routing table; if you want to advertise a default even without a local default, you can add always. The other options don’t specifically originate a default route: redistribute static would place static routes into OSPF (which could include a static default if configured), network defines which interfaces participate, and area assigns those interfaces to an OSPF area.

In OSPF, to have a router advertise a default route to the rest of the domain, you use the default-information originate command. This instruction causes a 0.0.0.0/0 route to be injected into OSPF, so neighboring routers learn how to forward traffic toward destinations beyond their own knowledge. The effect depends on having a default route in the router’s own routing table; if you want to advertise a default even without a local default, you can add always.

The other options don’t specifically originate a default route: redistribute static would place static routes into OSPF (which could include a static default if configured), network defines which interfaces participate, and area assigns those interfaces to an OSPF area.