A network administrator determines that falsified routing information is propagating through the network. What action can be used to address this threat?

When falsified routing information propagates through a network, it indicates that unauthorized or malicious routers are injecting incorrect routing data. The most effective mitigation is routing protocol authentication, which ensures that only trusted routers can participate in the routing process. Authentication methods like MD5 or plain text passwords verify the identity of routing peers before accepting their updates. Changing console passwords or updating IOS images address different security concerns (access control and software vulnerabilities respectively), while end-user authentication is unrelated to routing protocol security.