Shining Light on Dark Address Space

Abstract

In this report, we explore the degree to which commercial strategies, peering disputes, network failures, misconfiguration, and occasionally, malicious intent, lead to a partitioning of Internet topology. Specifically, we present a three-year study of the one-sided differences in Internet provider reachability. We focus on “dark address space”, or the range of topology accessible from one provider, but unreachable via one or more competitor networks. We present active and passive measurements of these differences on time scales ranging from several seconds to multiple months. We show that more than five percent of the currently routed Internet address space lacks global connectivity. Our analysis shows that the majority of this partitioned Internet topology includes broadband customers and United States military networks. Finally, we explore “murky” address space, or the transient announcement of unallocated or reserved address space. We find that the majority of murky address space announcements represent misconfiguration, while a smaller number may represent intentional misuse and cooption of the Internet routing infrastructure.