DNS, name System, is one in every of the foundational protocols for net to figure. It resolves hostnames to scientific disciplined addresses called informatics addresses that permits applications like net browsers and humans to use net or alternative networks simply. owing to its restricted practicality, it's wide open in several enterprise firewalls with a really less attention from enterprise security observation. because of of these factors, several tools have evolved to line up covert info tunneling channels through DNS which matches unobserved inflicting vital info exfiltration risks to organizations and money losses to ISPs. Hence, it is important to analyze and stop DNS tunneling. during this paper we tend to rehearse DNS summary, completely different DNS tunneling tools and techniques to dam it. thus DNS provides a mechanism to try to to mapping between hostnames and informatics address employing a distributed gradable info of system/service names and informatics addresses. A supply trying to find informatics address of any remote system or service is understood as DNS consumer.