What is the valid range of TCP ports?

• A. 1-1024
• B. 0-65535
• C. 1024-49151
• D. 49152-65535

Answer: (B)

The range of TCP ports spans from 0 to 65535, encompassing a total of 65536 different ports. This is because TCP (Transmission Control Protocol) utilizes a 16-bit number to represent port numbers, allowing for values from 0 through 2^16 - 1 (which equals 65535).

Within this range, there are specific classifications for ports:

• Ports 0 to 1023 are known as well-known ports, which are assigned to specific services and applications (like HTTP, HTTPS, FTP, etc.).

• Ports 1024 to 49151 are considered registered ports, which can be used by user applications and many third-party applications.

• Ports 49152 to 65535 are referred to as dynamic or private ports, primarily used by client programs when communicating with servers.

While options indicating smaller ranges cover specific classifications of ports, they do not represent the complete and valid range of TCP ports. Hence, the full span from 0 to 65535 accurately reflects all possible TCP port numbers.