Hyper-Specific Prefixes: Gotta Enjoy the Little Things in Interdomain Routing

Autonomous Systems (ASes) exchange reachability information between each other using BGP -- the de-facto standard inter-AS routing protocol. While IPv4 (IPv6) routes more specific than /24 (/48) are commonly filtered (and hence not propagated), route collectors still observe many of them. In this work, we take a closer look at those "hyper-specific" prefixes (HSPs). particular, analyze their prevalence, use cases, and whether operators them intentionally or accidentally. total number increases over time, most HSPs can only be seen by collector peers. Nonetheless, some constantly throughout an entire year propagate widely. We find that represent (internal) to peering infrastructure related address block relocations blackholing. hundreds add well-known databases, possibly accidentally leaked routes.