IP netblocks can be considered a neighborhood to which consecutive IP addresses belong. As in the real world, there are good and bad neighborhoods. Fortunately, sophisticated threat intelligence tools enable security engineers to distinguish one from the other.
Traditionally, users can check computers communicating over a network by using a simple ping command to find unresponsive or misbehaving nodes. A ping test sends packets to a server and reveals if the same number of packets were returned, as well as how long it took the destination to issue a response.