  Geographically locating an IP address is of interest for many purposes. There
are two major ways to obtain the location of an IP address: querying commercial
databases or conducting latency measurements. For structural Internet nodes,
such as routers, commercial databases are limited by low accuracy, while
current measurement-based approaches overwhelm users with setup overhead and
scalability issues. In this work we present our system HLOC, aiming to combine
the ease of database use with the accuracy of latency measurements. We evaluate
HLOC on a comprehensive router data set of 1.4M IPv4 and 183k IPv6 routers.
HLOC first extracts location hints from rDNS names, and then conducts
multi-tier latency measurements. Configuration complexity is minimized by using
publicly available large-scale measurement frameworks such as RIPE Atlas. Using
this measurement, we can confirm or disprove the location hints found in domain
names. We publicly release HLOC's ready-to-use source code, enabling
researchers to easily increase geolocation accuracy with minimum overhead.
