Which of the following will OSPF use when it chooses its router ID?

Which of the following will OSPF use when it chooses its router ID?

• A loopback interface that is configured with the highest IP address on the router
• The highest active interface IP address that is configured on the router
• The lowest active interface IP address that is configured on the router
• The highest active interface that participates in the routing process because of a specifically configured network statement

Explanation: A. The first preference for an OSPF router ID is an explicitly configured 32-bit address. This address is not included in the routing table and is not defined by the network command. If a router ID that is configured through the router-id command is not available, OSPF routers next use the highest IPv4 address available on a loopback interface, as loopbacks used as router IDs are also not routable addresses. Lacking either of these alternatives, an OSPF router will use the highest IPv4 address from its active physical interfaces.

Exam with this question: 2.7.5 Module Quiz - Single-Area OSPFv2 Configuration