Two complementary approaches to mapping network boundaries from traceroute paths recently emerged. Both approaches apply heuristics to inform inferences extracted from traceroute measurement campaigns. bdrmap used targeted traceroutes from a specific network, alias resolution probing techniques, and AS relationship inferences, to infer the boundaries of that specific network and the other networks attached at each boundary. MAPIT tackled the ambitious challenge of inferring all AS-level network boundaries in a massive archived collection of traceroutes launched from many different networks. Both were substantial contributions to the state-of-the-art, and inspired a collaboration to explore the potential to combine the approaches. We present and evaluate bdrmapIT , the result of that exploration, which yielded a more complete, accurate, and general solution to this persistent and central challenge of Internet topology research. bdrmapIT achieves 91.8%- 98.8% accuracy when mapping AS boundaries in two Internet-wide traceroute datasets, vastly improving on MAP-IT ’s coverage without sacrificing bdrmap ’s ability to map a single network. The bdrmapIT source code is available at https://git.io/fAsI0