LISTEN state in a TCP socket refers to: A TCP socket is ready and is listening for incoming connections A synchronization request has been sent The socket has received a synchronization request All of the above Question 12
The Correct Answer and Explanation is:
Correct Answer: A TCP socket is ready and is listening for incoming connections
Explanation:
In the Transmission Control Protocol (TCP), the LISTEN state is part of the TCP connection state machine, which defines the steps a TCP connection goes through from creation to termination. The LISTEN state plays a critical role in server-side socket programming.
When a TCP socket enters the LISTEN state, it means the application (such as a web server or mail server) has created a socket, bound it to an IP address and port number, and is now waiting (or listening) for incoming connection requests from remote clients. This is the first step in establishing a TCP connection from the server’s side.
To reach the LISTEN state, a server typically performs the following steps:
- Create a socket using the appropriate system call.
- Bind the socket to a specific IP address and port.
- Call
listen(), which places the socket into the LISTEN state.
At this point, the server is passively waiting for clients to initiate a connection. It is not actively sending or receiving data, nor has any connection been established yet.
Let’s clarify the other options in the question:
- “A synchronization request has been sent” refers to the SYN-SENT state, where the client sends a SYN packet to start the connection.
- “The socket has received a synchronization request” is part of the SYN-RECEIVED state, where the server has received the client’s SYN and is preparing to respond.
- “All of the above” is incorrect because each option refers to a different and distinct TCP state.
In summary, the LISTEN state only applies to a server socket that is waiting for incoming connections. It does not mean that any packets have been sent or received yet.
