RPKI and ROA Checks: A Practical BGP Route Security Guide for Network Teams

Resource Public Key Infrastructure (RPKI) is a security framework designed to protect the Border Gateway Protocol (BGP), which governs how Internet routes are advertised among autonomous systems (AS). Without built-in verification, BGP is vulnerable to errors and hijacks that can redirect traffic maliciously or cause outages. RPKI leverages cryptographic certificates to bind IP prefixes and AS numbers (ASNs) to verified holders.

These authorized holders publish Route Origin Authorizations (ROAs) that specify exactly which AS is permitted to announce a given IP prefix, including the maximum prefix length allowed. This framework allows other networks to check if a BGP route announcement has authorization from the legitimate resource holder, significantly improving routing security. [1][2]

When a network receives a BGP route announcement, it uses RPKI data and ROAs to validate the origin AS. This validation classifies routes into three distinct states:

1. Valid: The route announcement matches at least one ROA, confirming that the origin ASN is authorized for that prefix within the allowed maximum length. 2. Invalid: The ASN announcing the prefix is not authorized by any ROA, or the prefix length exceeds the maximum permitted in a matching ROA. 3. Unknown: No ROA exists covering the prefix, so the legitimacy of the announcement cannot be determined.

By classifying route announcements this way, network operators can filter or deprioritize invalid routes to prevent hijacks and misconfigurations, while carefully monitoring unknown routes for potential risks. [1][2]

To leverage RPKI effectively, network teams should integrate Route Origin Validation into their BGP routing infrastructure. This involves:

- Obtaining and managing ROAs for your IP prefixes through your Regional Internet Registry (RIR) or via hosted/self-hosted certificate authorities. - Running RPKI validators that fetch and verify ROA data, using Trust Anchor Locators (TALs) to establish the chain of trust. - Configuring routers to perform Route Origin Validation using the validator's data, categorizing routes accordingly. - Defining policies to handle valid, invalid, and unknown routes—for example, preferring valid routes and dropping invalid ones.

Regularly review and update your ROAs reflecting changes in your network and prefix announcements to avoid inadvertent invalid routes. Before provider changes or significant routing adjustments, run checks to identify any invalid or unknown routes to prevent outages. [2][1]

Implementing RPKI origin validation offers immediate benefits by reducing route hijacks caused by unauthorized announcements and accidental misconfigurations. It increases the trustworthiness of routing decisions and contributes to the global stability of Internet routing. However, RPKI currently only validates the origin AS of route announcements, not the full AS path, which limits detection of path-based attacks or route leaks.

Work on Secure BGP extensions, including path validation, is ongoing within the IETF. Hence, RPKI should be part of a broader BGP security strategy, paired with monitoring, filtering, and operational best practices to maximize network resilience. [1]

Network teams encounter several challenges when implementing RPKI and ROA checks, including incomplete ROA coverage leading to unknown routes, maintenance overhead in managing ROAs, and potential outages caused by strict filtering of invalid routes. To mitigate these, it is advisable to:

- Start with monitoring mode to observe route validity before enacting strict route filtering. - Engage with your RIR to ensure ROA data is accurate and up-to-date. - Automate ROA management where possible to reduce manual errors. - Communicate changes with providers and upstream peers. - Use tools and dashboards provided by RIRs and validator software to keep visibility on validation states.

This cautious, incremental approach helps prevent disruptions caused by premature rejection of routes and aligns team workflows with evolving routing security best practices. [2][1]