The Domain Name System (DNS) provides name service for the DARPA Internet and is widely accepted as a backbone to the Internet. DNS is one of the largest name services which are moreover operative even today, serving numerous hosts, users and networks in the unique way. There is an integrated service in the background which resolves FQDN (Fully Qualified Domain Name) names and other client names in IP addresses. Thanks to DNS, users can easily locate resources by simply typing the address they want to access e.g. www.google.com, which is translated by our computer using DNS service to the IP address 8.8.8.8. DNS wouldn’t work without its base which is usually integrated in the Active Directory or in the other file in some cases, where all the information, mappings of resources and its IP addresses are kept and stored. In the beginning there was a single file which mapped every single host name in the world to its valid IP address. As the time went by, the file was getting bigger and bigger by adding more mappings and information which resulted in the outgrow of the file’s capacity. That’s the main reason why DNS was developed. Thanks to the IPv6 standard and its expenditure and further development, the importance of DNS is even more multiplied as the new standard uses more complex and complicated IP addresses. This paper in proceeding will examine the installation, configuration and the ways queries are resolved by DNS server, there will be a little bit about DNS zones, transfers among them and zone delegation. The final part will examine the security component, potential attacks and the ways how to effectively protect from them.