Most search engines exploit spiders to implement the information gathering process. We present a technique to reduce the memory resources required by such spiders, improve the coverage and to provide for scaling through parallelization. The technique exploits the direct enumeration of Internet hosts through Domain Name Server. Tool bases on this technique have been successfully applied in a search engine for the ".it" domain but can be applied directly to other domains. We report statistics on the results of the use of our tools in this context