Embodiments of the present invention are directed to diagnosing problems in a dual stack network supporting Internet Protocol Version Six (IPV6). Inventoried information can be retrieved from an inventory system in response to a problem associated the dual stack network. It can be determined whether a mismatch exists between live customer address information associated with a customer edge router and the inventoried information. A notification can be generated in response to determining whether a mismatch exists. The notification includes information representing a cause of the problem and resolution of the problem.