Commonly at this point, whether you were provided some starting places or you figured some out as you were poking around in Google or the Internet registries, you have at least some IP addresses or maybe hostnames to work with. In either case, the domain name system (DNS) is one of the next steps. At a minimum, having a better understanding of the structure and use of DNS is important. The DNS is where Internet Protocol (IP) addresses are mapped to hostnames and vice versa. There are some really useful tools that are commonly used when prowling around DNS, and we’re going to take a look at those tools, since you likely want to figure out in more detail just what you are looking at and where it might be.