As DNS packet are mostly UDP-based, make it as a perfect platform for hackers to launch a well-known type of distributed denial of service (DDoS). The purpose of this attack is to saturate the DNS server availability and resources with unwanted DNS query traffic. This type of attack utilizes a large number of botnet and usually perform spoofing on the IP address of the targeted victim. While it is difficult to identify which one is legitimate or attack traffic, we take a different approach for spoofing detection strategies to protect the DNS server by utilizing Software Defined Networking (SDN). In this paper, we present CAuth, a novel mechanism that autonomously block the spoofing packet while authenticate the legitimate query. By manipulating Openflow control message, we design a collaborative approach between client and server network. Whenever a server controller receives query packet, it will send an authentication packet back to the client network and later the client controller also reply via authentication packet back to the server controller. The server controller will only forward the query to the respective server if it receives the replied authentication packet from the client. From the evaluation, CAuth instantly manage to block spoofing query packet while authenticate the legitimate query as soon as the mechanism started.