Shim6 is an important multihoming solution. This paper studies shim6 from several perspectives, including shim6 protocol implementation, shim6 mechanism optimization and security enhancement. In order to provide a shim6 research platform, we implement shim6 protocol on the Linux 2.6 platform as one of the first reference implementations. Based on this research platform, we refine the shim6 address switching mechanism, which reduces shim6 address switching time greatly. In addition, we propose an enhanced shim6 security mechanism to defeat reflection-type DoS/DDoS attacks launched from the multihomed site, by preventing source address spoofing in the multihomed site.