The IETF has developed several solutions that promote IPv4 and IPv6 co-existence, but they need to be thoroughly tested on a large scale, before they can actually be considered as viable solutions. In the following study we present an experimental evaluation of the two popular transitioning technologies: NAT64 and Dual-Stack Lite. Our first goal is to identify how well current applications, protocols and online services interoperate with these technologies and to detect their potential failures. Our second goal is to use a stream-oriented flow query language NFQL, to formulate queries that can find those failures by scanning through traces of NetFlow records. We identified several applications that fail under NAT64, and we analyze how to detect these failures in an automated fashion.