In the previous recipe, we saw how to identify a normal operation of DNS. In this recipe, we will learn how to discover problematic behavior of DNS, and how to figure out its source.
A DNS problem can result in bad performance while browsing the Internet, slow network while working inside the organization network, or any other performance issues. We will see how to isolate these problems and how to find out whether it is a DNS issue or not.
There are two major types of problems in DNS:
In both cases, connect your Wireshark to the network in the following order when you suspect an Internet connectivity problem: