During the course to deploy IPv6, we found several critical implementation and operational issues which distract user and possibly prevent wider deployment of IPv6. Among the problems we noticed, Domain Name System (DNS) related issues are significant. Some of the problems cause longer delay during the process to make a connection to a given node. In worst case, the delay will be 60 seconds or more. This amount of delay may mislead users for some idea that IPv6 is not good technology, which is not accurate. In this paper, we will reveal six cases which related to DNS server and resolver implemetation we found during our study in detail.

To overcome these problem, fix to the servers are essential. To know how these cases affect overall behavior of the DNS, we created a tool to find misbehaving servers. We applied this tool to servers in ".JP" domain and found that there are 0.11% of servers in ".JP" domain have some problem. The other way to solve or ease the problem is to find workaround in client side. We will propose two workarounds, with a sample implementation.