Exploring DNS reconnaissance
The DNS is an application layer protocol that allows a system such as a computer to resolve a hostname to an IP address. While there are so many devices on a network, especially on the internet, remembering the IP address of each web server is quite challenging. Using DNS, a system administrator can configure each device with both an IP address and a hostname. Using a hostname is a lot easier to remember, such as www.packtpub.com or www.google.com. However, do you know the IP addresses of the servers that are hosting those websites for Packt and Google? You probably don't, and that's OK because around the world on the internet, there is a hierarchy of special servers that contain the records of public hostnames and their IP addresses. These are known as DNS servers.
A DNS server is like a traditional telephone directory, with a list of people and their telephone numbers. On a DNS server, you can find records of the hostnames of people, as...
