External reconnaissance is done outside of the organization's network and systems. It is normally targeted by exploiting the carelessness of users of an organization. There are several ways in which this can be done.
Organizations dispose of obsolete devices in a number of ways, such as through bidding, sending to recyclers, or dumping them in storage. There are serious implications for these methods of disposal. Google is one of the companies that are thorough in the way they dispose of devices that may have contained user data. The company destroys its old hard drives from its data centers to prevent the data that they contained from being accessed by malicious people. The hard drives are put into a crusher that pushes steel pistons up the center of the disks, rendering them unreadable. This process continues until the machine spits out tiny pieces of the hard drive, which are then sent to a recycling center. This is a rigorous and fail-proof exercise...