Which of the following protocols uses both TCP and UDP?

Application layer protocol DNS uses TCP and UDP both at the transport layer.

Solution

The answer to the question: Which of the following protocols uses both TCP and UDP? is option D, i.e., DNS. The application layer protocol Domain Name Server, abbreviated as DNS, uses both TCP and UDP at the transport layer. It uses port number 53 at TCP for the transfer of information between zones. It uses UDP when a client communicates to the DNS server. Other protocols like FTP and SMTP use only TCP at the transport layer. Telnet uses only UDP at the transport layer.

☛ Related Questions:

• The wildcard in a WHERE clause is useful when?
• Which header file includes a function for the variable number of arguments?
• Which two are valid constructors for Thread?
• Which statement is true about a static nested class?