-
Which one of the following uses UDP as the transport protocol?
-
- HTTP
- Telnet
- DNS
- SMTP
- HTTP
Correct Option: C
Either TCP or UDP can be used as transport protocol to transport DNS protocol messages, connecting to server port 53 for either. Ordinary DNS request can be made with TCP, through convention dictates the use of UDP for normal operation. TCP must be used for zone transfers, however, because of the danger of dropping records with an unreliable delivery protocol such as UDP.