A port scanner is basically a software utility that can be used to determine which ports a host is accepting connections on. For example, if I wanted to see if I could pull up a web page from any hosts on my network, I would scan my subnet to see if any hosts have port 80 open. But this is a basic example. The information obtained from a port scanner can help attackers read between the lines and determine the purpose of a host on their network. For example, if a port scanner showed that a host had port 9100 open, you could reasonably assume that the host you scanned is either a printer or a print server since port 9100 is used for printing. I know, I know, printers are boring. But it is amusing to think that you could send print jobs to your neighbor’s printer and print anything you wanted to after identifying their printer with a port scanner (don’t actually do that, it’s just funny to think about). But think how far an attacker could take this concept. By identifying the s...