Refer to the exhibit. After configuring OSPF in R1, some external destinations in the network became unreachable. Which action resolves the issue?
Refer to the exhibit. After configuring OSPF in R1, some external destinations in the network became unreachable. Which action resolves the issue?
The error message '%OSPF-4-FLOOD_WAR' indicates that there is a conflict in the OSPF router IDs in the network. OSPF router IDs must be unique within an OSPF domain. Since the router R1 has the OSPF router ID 10.255.255.1 and it is being used in multiple places, it leads to a conflict, resulting in the external destinations becoming unreachable. To resolve this issue, it is necessary to change the OSPF router ID on R1 to a unique value and then clear the OSPF process to ensure the changes take effect, thereby eliminating the conflict and restoring connectivity.
The OSPF Router ID 10.255.255.1 is not unique, thus "OSPF-4-FLOOD_WAR" error message is generated on the affected routers. R1 is one of the affected devices, so "C) Change the R1 router ID from 10.255.255.1 to a unique value and clear the process" resolves the issue.
"show ip ospf database self-originate" displays LSAs from the local router = R1. R1 has the OSPF Router ID 10.255.255.1 (displayed as "adv-rtr" or "ADV Router"). As we see, R1 originates a type 5 LSA with a link ID of 0.0.0.0, which is the default route (from default-information originate). That is where the router ID conflict occurs.
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/118880-technote-ospf-00.html OSPF-4-FLOOD_WAR "...Type-5 LSAs when there is a duplicate router ID in different OSPF Areas"
https://community.cisco.com/t5/switching/ospf-4-flood-war-messages-after-config-change/td-p/2506500 "For OSPF to function correctly the IP addresses of transit networks must be unique. If it is not unique the conflicting routers reports this error message. In the error message the router with the OSPF router ID reported as adv-rtr reports this message."
C correct answer Ref: https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/9237-9.html
C is corerct