Remote computing resource service providers, including online retailers, provide externally facing computer systems that allow users to interact with the service provider. Furthermore, the service provider may maintain computer systems and services inside an isolated network not exposed to users. Occasionally, service providers may test these externally facing computer systems using one or more external hosts operating on a public network. As a result side effects may occur within the isolated network that is not accessible from the public network. The side effects may be recorded in a queue which may be accessed from inside the isolated network by one or more services. The one or more services may then reverse the side effects based at least in part on information contained in the queue.