100-150 Question 15
Single answerA network technician is troubleshooting an issue where a user cannot access a website. Upon investigation, the technician discovers that the user's computer is able to resolve the website's IP address but is unable to establish a connection. At which layer of the TCP/IP model is the issue most likely occurring?
- A
Application Layer
- B
Transport Layer
- C
Internet Layer
- D
Network Access Layer
Show answer and explanation
Correct answer: B
Explanation
The issue is most likely occurring at the Transport Layer of the TCP/IP model. Although the user's computer can resolve the IP address of the website (indicating that the Application and Internet Layers are functioning correctly), the inability to establish a connection points to a problem with the Transport Layer, such as a TCP handshake failure or blocked ports.
- A. Incorrect.
The Application Layer is responsible for handling application-specific protocols like HTTP or DNS. Since the computer can resolve the IP address, it indicates that application-layer protocols like DNS are functioning correctly.
- B. Correct.
The Transport Layer is responsible for establishing end-to-end communication between devices using protocols like TCP or UDP. If the user cannot establish a connection despite resolving the IP address, the issue is likely at this layer, such as a problem with TCP handshake.
- C. Incorrect.
The Internet Layer is responsible for addressing and routing packets based on IP addresses. Since the IP address is already resolved, this layer is not the likely source of the issue.
- D. Incorrect.
The Network Access Layer deals with the physical transmission of data over the network medium. If there were a problem at this layer, the user would likely not be able to communicate with the network at all, including resolving the IP address.