Network reconnaissance is not what it used to be. The surge in cloud use and temporary infrastructure has turned standard network discovery on its head. Security folks on both sides of the fence are struggling to identify organizational assets as these trends accelerate. This talk will describe how to build an internet-scale network discovery platform using open source software (some old, some new) and a wide range of data sources, most of which are available at zero cost. For the last two years, the presenter has been using this platform to accelerate penetration tests, provide accurate pre-sales project scoping, and help defenders get a handle on their network footprint.