Unexpected finding: Major networks undermining BGP security feature

Cloudflare's analysis of RFC 9234 adoption revealed an unexpected obstruction: two Tier-1 network operators are stripping the Only to Customer (OTC) attribute designed to prevent Border Gateway Protocol (BGP) route leaks. The security feature, introduced in RFC 9234, allows routers to autonomously block unintended route propagation by encoding relationship intents directly in BGP updates. While measuring implementation rates through their global peering infrastructure, researchers discovered these major transit providers actively removing the OTC marker from routes they forward, undermining the protocol's leak prevention capabilities. Cloudflare is currently engaging with the operators to restore attribute propagation.