DNS Tunneling – Domain Name Server
"If, on one system, it is possible to transmit bits to another in any form, and in turn receive a reply as a result of that transmission, then it is inherently impossible to effectively limit or censor the flow of data between them."
The mechanism for DNS tunnel comprises of binding or can say encapsulating the binary data within DNS queries and replies in order to implement the DNS name lookup itself , using base32 and base64 encoding, in order to enable the bi-directional carrier for the data. Hence, the user may also tunnel the data simultaneously to remote system, while domain name lookups on a network.