The well-known traceroute probing method discovers links between interfaces on Internet routers. IP alias resolution, the process of identifying IP addresses belonging to the same router, is a critical step in producing Internet topology maps. We compare the performance and accuracy of known alias resolution techniques, propose some enhancements, and suggest a practical combination of techniques that can produce the most accurate and complete IP-to-router mapping at macroscopic scale. Categories and Subject Descriptors C.2.3 [Computer-Communication Networks]: Network Operations--Network monitoring; C.2.1 [Computer-Communication Networks]: Network Architecture and Design--Network topology General Terms Measurement, Experimentation Keywords Alias resolution, Mercator, iffinder, Ally, RadarGun, APAR, kapar, DisCarte