Using DNS is the first step for accessing any website on internet. DNS is used to map domain names to IP addresses of their servers. As inoffensive as it looks, attackers still find ways to exploit DNS. Hackers use this protocol to launch DDoS amplification attacks on their targets. They request for such a query which will give a huge response. Thus, the attack is amplified. Because of these attacks, many organizations suffer losses. Executing a DDoS attack is very easy for the attacker. So, right preventive measures should be applied to mitigate these attacks. In this paper, we study the working of DNS amplification attack and propose a novel solution to mitigate it. DNS packets have a field called transaction ID to prevent DNS cache poisoning. With the help of transaction ID in the DNS packets, we can track legitimate responses among the traffic during the attack. With this strategy, we can mitigate an DNS amplification attack