With the explosive expansion of the Internet, many fundamental and popular Internet services such as WWW and e-mail are becoming more and more important and are indispensable for the human's social activities. As one technique to operate the systems reliably and efficiently, the way of introducing multihomed networks attracts much attention. However, conventional route selection mechanisms on multihomed networks reveal problems in terms of properness of route selection and dynamic traffic balancing which are two key criteria of applying multihomed networks. In this paper, we propose an improved dynamic route selection mechanism based on multipath DNS (Domain Name System) round trip time to address the existing problems. The evaluation results on the WWW system and the e-mail system indicate that the proposal is effective for a proper route selection based on the network status as well as for dynamic traffic balancing on multihomed networks and we also confirmed the resolution of problems that occur in the case of conventional mechanisms.