Domain Name System is used to resolve host names into the IP addresses that are used to locate the host.
To resolve a domain name, the client sends a request with the IP address or a host name to the server. The server then responds with the host name or the IP address where appropriate. This protocol uses UDP as its underlying process.
As a result of using UDP, the process is fast, but not reliable. Furthermore, if the response by the server exceeds 512 bytes of data, it sends the data back to the client with the first 512 bytes and a truncated flag. The client has to resubmit the request using TCP.
The reason for this is that there is no guarantee that the receiving host will be able to reassemble the IP datagram exceeding 576 bytes. For safety, many protocols limit the user data to 512 bytes.
T/TCP is the perfect candidate for the DNS protocol. It can communicate at speeds approaching that of UDP, and it has the reliability of TCP.