What is the purpose of the MANRS initiative and which of the following are its four core actions?

• A. Enhancing router performance, improving startup times, increasing logging, and global monitoring.
• B. Filtering and rejecting bogus routes; authenticating BGP sessions; preventing route leaks; global monitoring.
• C. Producing secure prefixes, encrypting BGP sessions, enforcing route acceptance, and network auditing.
• D. Advertising routes efficiently, reducing churn, securing BGP with TLS, and remote monitoring.

Answer: (B)

MANRS focuses on improving the safety of inter-domain routing by encouraging operators to adopt a small set of practical, verifiable actions that reduce common routing incidents. The four core actions work together to stop misconfigurations and malicious activity from propagating across the Internet.

First, filtering and rejecting bogus routes. By implementing filters that drop invalid or suspicious routes, a network prevents incorrect prefixes, incorrect origin AS information, or other malformed data from being announced or accepted. This containment directly reduces the chances of traffic being redirected to the wrong place or hijacked.

Second, authenticating BGP sessions. Ensuring that BGP peering sessions come from trusted neighbors and are protected against tampering makes it much harder for an attacker to inject or alter routing information. This authentication acts like a shield around the peering relationship, so only legitimate neighbors can exchange routes.

Third, preventing route leaks. Properly applied routing policies ensure that routes learned from one neighbor are not inappropriately advertised to other peers. This avoids situations where internal or regional routes leak into the global Internet in ways that misroute traffic or cause instability.

Fourth, global monitoring. Making routing data publicly observable and coordinating through shared data sources allows operators to detect anomalies quickly, verify suspected hijacks or leaks, and respond in a timely, coordinated manner.

These actions emphasize verification, containment, and visibility, which are the core ideas MANRS promotes to improve the reliability and security of the global routing system.