In this presentation I will go into the difficulties I encountered trying to move TransIP from its own proprietary DNS solution "TransDNS" to an open source solution. Topics for the talk are: - Why we had a closed source solution in the first place - Problems caused by RFC non-compliance, specifically related to wildcard handling - Missing features in the selected OSS solution (PowerDNS) and how we fixed them - How we tested and rolled out the final solution - Scaling issues we ran into once it was deployed and how we solved them