Which of the following is the correct IP protocol number for UDP?

The correct IP protocol number for UDP (User Datagram Protocol) is 17. In the Internet Protocol suite, different protocols are identified using specific numerical codes. UDP is one of the core transport layer protocols, designed for low-latency and loss-tolerating connections between applications on the Internet. Its role is primarily to enable faster message transmission without the overhead of ensuring reliability, which is a characteristic of TCP (Transmission Control Protocol), assigned the protocol number 6.

Understanding the protocol number associated with UDP is essential for network troubleshooting and configuration tasks, as it helps in recognizing and managing traffic at the network layer. Each transport protocol has its own predefined number, and knowing these can aid in various networking concepts, such as creating access control lists (ACLs) or analyzing packet captures.