Question

You are deploying single-area OSPFv2 on a new WAN router named R4. The router has no loopback interfaces configured, and its physical interfaces receive IP addresses via DHCP after OSPF starts. You need R4 to always use a stable, predictable router ID of 4.4.4.4 that will not change even if interfaces flap or reboot in a different order. Which action guarantees this outcome?

Accepted Answer

Configure 'router-id 4.4.4.4' under the OSPF process, then clear the OSPF process or reload the router

Answer

Assign the IP address 4.4.4.4 to the highest-numbered physical interface so OSPF selects it automatically

Answer

Create a loopback0 interface with IP 4.4.4.4 and rely on OSPF choosing the highest loopback address

Answer

Set the OSPF priority to 4 on all interfaces so the router advertises 4.4.4.4 as its ID